Try to use mmap() to speed access to the database file on windows, linux,

and mac.

FossilOrigin-Name: fff2be60779571c8fb89158db976ec3755e9a223

manifest

@@ -1,5 +1,5 @@
-C If\sthe\sSQLITE_TRACE_SIZE_LIMIT\scompile-time\sparameter\sis\sset\sto\sa\spositive\ninteger\sthen\slimit\sthe\sexpansion\sof\sstrings\sand\sblobs\sin\strace\soutput\sto\napproximately\sthat\smany\sbytes.
+C Try\sto\suse\smmap()\sto\sspeed\saccess\sto\sthe\sdatabase\sfile\son\swindows,\slinux,\nand\smac.
-D 2013-04-02T13:56:53.795
+D 2013-04-04T00:40:17.148
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in aafa71d66bab7e87fb2f348152340645f79f0244
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -118,23 +118,23 @@ F src/alter.c f8db986c03eb0bfb221523fc9bbb9d0b70de3168
 F src/analyze.c d5f895810e8ff9737c9ec7b76abc3dcff5860335
 F src/attach.c 1816f5a9eea8d2010fc2b22b44f0f63eb3a62704
 F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
-F src/backup.c b2cac9f7993f3f9588827b824b1501d0c820fa68
+F src/backup.c b266767351ae2d847716c56fcb2a1fea7c761c03
 F src/bitvec.c 19a4ba637bd85f8f63fc8c9bae5ade9fb05ec1cb
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
-F src/btree.c 62ba5954765efc711c873a20a53f60d9fc2843ba
+F src/btree.c 5f2c4fe72f663bba837c5d01a732799c1d1c93f8
-F src/btree.h 3ad7964d6c5b1c7bff569aab6adfa075f8bf06cd
+F src/btree.h d9490cd37aaeb530a41b07f06e1262950b1be916
 F src/btreeInt.h eecc84f02375b2bb7a44abbcbbe3747dde73edb2
 F src/build.c 083da8466fd7e481cb8bd5264398f537507f6176
 F src/callback.c d7e46f40c3cf53c43550b7da7a1d0479910b62cc
 F src/complete.c dc1d136c0feee03c2f7550bafc0d29075e36deac
-F src/ctime.c 2a5f251fcd7393808df77ccfc817e7058df08c4c
+F src/ctime.c 16658a257bc6a3ca8d8961f574cf61a57e4d6faf
 F src/date.c 067a81c9942c497aafd2c260e13add8a7d0c7dd4
 F src/delete.c aeabdabeeeaa0584127f291baa9617153d334778
 F src/expr.c 48048fca951eedbc74aa32262154410d56c83812
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c e16942bd5c8a868ac53287886464a5ed0e72b179
 F src/func.c 48987c025d69399f59a1c2a553cea5da41bf105d
-F src/global.c e59ecd2c553ad0d4bfbc84ca71231336f8993a7a
+F src/global.c d2494a1cea8f66a2cab8258449df07f8f0ae6330
 F src/hash.c ac3470bbf1ca4ae4e306a8ecb0fdf1731810ffe4
 F src/hash.h 8890a25af81fb85a9ad7790d32eedab4b994da22
 F src/hwtime.h d32741c8f4df852c7d959236615444e2b1063b08
@@ -143,7 +143,7 @@ F src/journal.c b4124532212b6952f42eb2c12fa3c25701d8ba8d
 F src/legacy.c a199d7683d60cef73089e892409113e69c23a99f
 F src/lempar.c cdf0a000315332fc9b50b62f3b5e22e080a0952b
 F src/loadext.c 1422eba4aa2b1fb5f7b3aef574752272477d21e2
-F src/main.c 379160ec3680e3009aa4978eac47027c3ef27ac5
+F src/main.c 54a841854734b6731c4d026834788cac6a19f3d1
 F src/malloc.c fe085aa851b666b7c375c1ff957643dc20a04bf6
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c 437c7c4af964895d4650f29881df63535caaa1fa
@@ -157,34 +157,34 @@ F src/mutex_noop.c 7682796b7d8d39bf1c138248858efcd10c9e1553
 F src/mutex_unix.c c3a4e00f96ba068a8dbef34084465979aaf369cc
 F src/mutex_w32.c 32a9b3841e2d757355f0012b860b1bc5e01eafa0
 F src/notify.c 976dd0f6171d4588e89e874fcc765e92914b6d30
-F src/os.c e1acdc09ff3ac2412945cca9766e2dcf4675f31c
+F src/os.c 809d0707cec693e1b9b376ab229271ad74c3d35d
-F src/os.h 027491c77d2404c0a678bb3fb06286f331eb9b57
+F src/os.h ae08bcc5f6ec6b339f4a2adf3931bb88cc14c3e4
 F src/os_common.h 92815ed65f805560b66166e3583470ff94478f04
-F src/os_unix.c 21a36fa0b3753609b6606b30d9338d4bb6b24696
+F src/os_unix.c f0ecce40d92469d5cc737ae883e776eb3e5c0af5
-F src/os_win.c 9fe5356f943425ab8431237bd3a4297044928b70
+F src/os_win.c 3265df8c762e0b8caf8d02b3352fa8c22e91ae6b
-F src/pager.c 3e9a15939684b0af441325f05335331b15979c9d
+F src/pager.c 2e68df46d4086027cb6b527d47a6dedbf1a6b7ec
-F src/pager.h 1109a06578ec5574dc2c74cf8d9f69daf36fe3e0
+F src/pager.h 5cb78b8e1adfd5451e600be7719f5a99d87ac3b1
 F src/parse.y 5d5e12772845805fdfeb889163516b84fbb9ae95
 F src/pcache.c f8043b433a57aba85384a531e3937a804432a346
-F src/pcache.h 1b5dcc3dc8103d03e625b177023ee67764fa6b7c
+F src/pcache.h a5e4f5d9f5d592051d91212c5949517971ae6222
 F src/pcache1.c 9fd22671c270b35131ef480bbc00392b8b5f8ab9
-F src/pragma.c 9f0ee3d74a7f33eeeff40a4b014fc3abf8182ce2
+F src/pragma.c 682e97f3e3b77fd6c9b569eabfbf4a14c987aca3
 F src/prepare.c 310eaff1ee5f3c700b3545afb095cfe9346efc3a
 F src/printf.c 4a9f882f1c1787a8b494a2987765acf9d97ac21f
 F src/random.c cd4a67b3953b88019f8cd4ccd81394a8ddfaba50
 F src/resolve.c 9079da7d59aed2bb14ec8315bc7f720dd85b5b65
 F src/rowset.c 64655f1a627c9c212d9ab497899e7424a34222e0
 F src/select.c 01540bcd3df3c8f1187158e77986028b1c667258
-F src/shell.c 7c41bfcd9e5bf9d96b9215f79b03a5b2b44a3bca
+F src/shell.c 319b7791cee6c763b60fde1b590bfaf62613cf37
-F src/sqlite.h.in 8d9e83d965f364ff99ebf4b653d0683d05df3900
+F src/sqlite.h.in faeb6b3470193e599d79289f77f984b8a78136e1
 F src/sqlite3.rc fea433eb0a59f4c9393c8e6d76a6e2596b1fe0c0
 F src/sqlite3ext.h 7183ab832e23db0f934494f16928da127a571d75
-F src/sqliteInt.h 0f8f05ee4db4ba9120b38f7a3992b325698f6e8a
+F src/sqliteInt.h 1664dc5ad6f8d4dab871416628aa3271044d66c0
-F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
+F src/sqliteLimit.h 1097d2c541147d303e66515040067c6bfcf8cf21
 F src/status.c bedc37ec1a6bb9399944024d63f4c769971955a9
 F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
 F src/tclsqlite.c 9a716c737590d2f129d71c8fc7065e5aba0e7222
-F src/test1.c ff3e68eedfbd858c9b89cf03e3db233cd29be1d0
+F src/test1.c 26e66b839f42c2eed6833f9023e0098f0d863f35
 F src/test2.c 4178056dd1e7d70f954ad8a1e3edb71a2a784daf
 F src/test3.c 3c3c2407fa6ec7a19e24ae23f7cb439d0275a60d
 F src/test4.c bf9fa9bece01de08e6f5e02314e4af5c13590dfa
@@ -226,7 +226,7 @@ F src/test_spellfix.c 56dfa6d583ac34f61af0834d7b58d674e7e18e13
 F src/test_sqllog.c bc50e5afeb7fb50e77b4594e42302df9d05446aa
 F src/test_stat.c d1569c7a4839f13e80187e2c26b2ab4da2d03935
 F src/test_superlock.c 2b97936ca127d13962c3605dbc9a4ef269c424cd
-F src/test_syscall.c a992d8c80ea91fbf21fb2dd570db40e77dd7e6ae
+F src/test_syscall.c 7e8293e4e6971b0f44c7f7f37b1315a8cc9f6018
 F src/test_tclvar.c f4dc67d5f780707210d6bb0eb6016a431c04c7fa
 F src/test_thread.c e286f2173563f2a1747c24bcda6b9d030bf4f4e4
 F src/test_vfs.c fb16b2d9938cf0c1afc5a423b55b952fcc024275
@@ -249,8 +249,8 @@ F src/vdbemem.c 833005f1cbbf447289f1973dba2a0c2228c7b8ab
 F src/vdbesort.c 4fad64071ae120c25f39dcac572d716b9cadeb7f
 F src/vdbetrace.c a22263ab47f6ba4fcd176515cec1e732866b25f0
 F src/vtab.c b05e5f1f4902461ba9f5fc49bb7eb7c3a0741a83
-F src/wal.c f5c7b5027d0ed0e9bc9afeb4a3a8dfea762ec7d2
+F src/wal.c 94b5fed2df988fb12f5bf17256e2840e56957a85
-F src/wal.h 29c197540b19044e6cd73487017e5e47a1d3dac6
+F src/wal.h a4d3da523d55a226a0b28e9058ef88d0a8051887
 F src/walker.c 3d75ba73de15e0f8cd0737643badbeb0e002f07b
 F src/where.c 4ad2329c439a30ddb915a780f6f80bdffafe3a64
 F test/8_3_names.test 631ea964a3edb091cf73c3b540f6bcfdb36ce823
@@ -314,6 +314,7 @@ F test/boundary3.tcl 8901d6a503d0bf64251dd81cc74e5ad3add4b119
 F test/boundary3.test 56ef82096b4329aca2be74fa1e2b0f762ea0eb45
 F test/boundary4.tcl 0bb4b1a94f4fc5ae59b79b9a2b7a140c405e2983
 F test/boundary4.test 89e02fa66397b8a325d5eb102b5806f961f8ec4b
+F test/btreefault.test 06899a377f31a8c1a3048ec69831522d4e5c6045
 F test/busy.test 76b4887f8b9160ba903c1ac22e8ff406ad6ae2f0
 F test/cache.test 13bc046b26210471ca6f2889aceb1ea52dc717de
 F test/capi2.test e8b18cc61090b6e5e388f54d6b125d711d1b265a
@@ -369,7 +370,7 @@ F test/cse.test 277350a26264495e86b1785f34d2d0c8600e021c
 F test/ctime.test 7bd009071e242aac4f18521581536b652b789a47
 F test/date.test f3228180c87bbe5d39c9397bf001c0095c3821b9
 F test/dbstatus.test 207e5b63fcb7b9c3bb8e1fdf38ebd4654ad0e54b
-F test/dbstatus2.test bf7396af964b89e39435babbcdf296ae8fc5f10a
+F test/dbstatus2.test f329941d5f4a8bc0ba6ec5735897ef0cf34e2f5f
 F test/default.test 6faf23ccb300114924353007795aa9a8ec0aa9dc
 F test/delete.test a065b05d2ebf60fd16639c579a4adfb7c381c701
 F test/delete2.test 3a03f2cca1f9a67ec469915cb8babd6485db43fa
@@ -403,7 +404,7 @@ F test/eqp.test 46aa946dd55c90635327898275d3e533d23a9845
 F test/errmsg.test 050717f1c6a5685de9c79f5f9f6b83d7c592f73a
 F test/eval.test bc269c365ba877554948441e91ad5373f9f91be3
 F test/exclusive.test a1b324cb21834a490cd052d409d34789cfef57cb
-F test/exclusive2.test 372be98f6de44dd78734e364b7b626ea211761a6
+F test/exclusive2.test 354bdabe299a2546c898dff42f79079ff1590d88
 F test/exec.test e949714dc127eaa5ecc7d723efec1ec27118fdd7
 F test/exists.test 8f7b27b61c2fbe5822f0a1f899c715d14e416e30
 F test/expr.test 67c9fd6f8f829e239dc8b0f4a08a73c08b09196d
@@ -508,7 +509,7 @@ F test/fts4merge2.test 5faa558d1b672f82b847d2a337465fa745e46891
 F test/fts4merge3.test aab02a09f50fe6baaddc2e159c3eabc116d45fc7
 F test/fts4unicode.test 25ccad45896f8e50f6a694cff738a35f798cdb40
 F test/full.test 6b3c8fb43c6beab6b95438c1675374b95fab245d
-F test/func.test b058483c17952eff7797b837bbb61e27e6b05606
+F test/func.test a4f24707e6af0bcd4cb5b856af4462db40b047b1
 F test/func2.test 772d66227e4e6684b86053302e2d74a2500e1e0f
 F test/func3.test 001021e5b88bd02a3b365a5c5fd8f6f49d39744a
 F test/fuzz-oss1.test 4912e528ec9cf2f42134456933659d371c9e0d74
@@ -526,7 +527,7 @@ F test/in2.test 5d4c61d17493c832f7d2d32bef785119e87bde75
 F test/in3.test 3cbf58c87f4052cee3a58b37b6389777505aa0c0
 F test/in4.test 64f3cc1acde1b9161ccdd8e5bde3daefdb5b2617
 F test/in5.test 99f9a40af01711b06d2d614ecfe96129f334fba3
-F test/incrblob.test e7ef2a6094d9b5eb7284c21af2c07644eefffe7d
+F test/incrblob.test 2100cb8964e4a106e5ca9bf80e2c5c3e8be33f77
 F test/incrblob2.test edc3a96e557bd61fb39acc8d2edd43371fbbaa19
 F test/incrblob3.test aedbb35ea1b6450c33b98f2b6ed98e5020be8dc7
 F test/incrblob4.test 09be37d3dd996a31ea6993bba7837ece549414a8
@@ -611,7 +612,7 @@ F test/mallocH.test 79b65aed612c9b3ed2dcdaa727c85895fd1bfbdb
 F test/mallocI.test a88c2b9627c8506bf4703d8397420043a786cdb6
 F test/mallocJ.test b5d1839da331d96223e5f458856f8ffe1366f62e
 F test/mallocK.test d79968641d1b70d88f6c01bdb9a7eb4a55582cc9
-F test/malloc_common.tcl 2930895b0962823ec679853e67e58dd6d8198b3c
+F test/malloc_common.tcl 9a98856549bfb3fab205edbc1317216edc52e70d
 F test/manydb.test 28385ae2087967aa05c38624cec7d96ec74feb3e
 F test/mem5.test c6460fba403c5703141348cd90de1c294188c68f
 F test/memdb.test 708a028d6d373e5b3842e4bdc8ba80998c9a4da6
@@ -630,6 +631,8 @@ F test/misc5.test 528468b26d03303b1f047146e5eefc941b9069f5
 F test/misc6.test 953cc693924d88e6117aeba16f46f0bf5abede91
 F test/misc7.test dd82ec9250b89178b96cd28b2aca70639d21e5b3
 F test/misuse.test ba4fb5d1a6101d1c171ea38b3c613d0661c83054
+F test/mmap1.test df5105f08e6000e57b4de7e748f8c2ae3fed75da
+F test/mmap2.test 62dbb5d718e66d654d232116c5a2d96e26a071a5
 F test/multiplex.test e08cc7177bd6d85990ee1d71100bb6c684c02256
 F test/multiplex2.test 580ca5817c7edbe4cc68fa150609c9473393003a
 F test/multiplex3.test d228f59eac91839a977eac19f21d053f03e4d101
@@ -651,14 +654,14 @@ F test/oserror.test 50417780d0e0d7cd23cf12a8277bb44024765df3
 F test/pager1.test 31c04bec797dda1bde337810b52efa08d1f1f08e
 F test/pager2.test 745b911dde3d1f24ae0870bd433dfa83d7c658c1
 F test/pager3.test 3856d9c80839be0668efee1b74811b1b7f7fc95f
-F test/pagerfault.test 452f2cc23e3bfcfa935f4442aec1da4fe1dc0442
+F test/pagerfault.test fc2e37b2da626826dd54bb13720b4d721719b660
 F test/pagerfault2.test 1f79ea40d1133b2683a2f811b00f2399f7ec2401
 F test/pagerfault3.test f16e2efcb5fc9996d1356f7cbc44c998318ae1d7
-F test/pageropt.test 9191867ed19a2b3db6c42d1b36b6fbc657cd1ab0
+F test/pageropt.test 32cb5a6ed7ccddf8e8c842cb44240bd9340223ce
 F test/pagesize.test 1dd51367e752e742f58e861e65ed7390603827a0
 F test/pcache.test 065aa286e722ab24f2e51792c1f093bf60656b16
 F test/pcache2.test a83efe2dec0d392f814bfc998def1d1833942025
-F test/permutations.test 360b92859c0af814b3fe10b68746936389606501
+F test/permutations.test b6cb45ce4d3193b831231025c9d30c77317dd240
 F test/pragma.test 60d29cd3d8098a2c20bf4c072810f99e3bf2757a
 F test/pragma2.test 3a55f82b954242c642f8342b17dffc8b47472947
 F test/printf.test ec9870c4dce8686a37818e0bf1aba6e6a1863552
@@ -731,7 +734,7 @@ F test/softheap1.test c16709a16ad79fa43b32929b2e623d1d117ccf53
 F test/sort.test 0e4456e729e5a92a625907c63dcdedfbe72c5dc5
 F test/speed1.test f2974a91d79f58507ada01864c0e323093065452
 F test/speed1p.explain d841e650a04728b39e6740296b852dccdca9b2cb
-F test/speed1p.test c4a469f29f135f4d76c55b1f2a52f36e209466cc
+F test/speed1p.test b180e98609c7677382cf618c0ec9b69f789033a8
 F test/speed2.test 53177056baf6556dcbdcf032bbdfc41c1aa74ded
 F test/speed3.test d32043614c08c53eafdc80f33191d5bd9b920523
 F test/speed4.test abc0ad3399dcf9703abed2fff8705e4f8e416715
@@ -747,8 +750,8 @@ F test/subselect.test d24fd8757daf97dafd2e889c73ea4c4272dcf4e4
 F test/substr.test 18f57c4ca8a598805c4d64e304c418734d843c1a
 F test/superlock.test 1cde669f68d2dd37d6c9bd35eee1d95491ae3fc2
 F test/sync.test a34cd43e98b7fb84eabbf38f7ed8f7349b3f3d85
-F test/syscall.test bea9bf329bff733c791310244617c2a76974e64a
+F test/syscall.test a653783d985108c4912cc64d341ffbbb55ad2806
-F test/sysfault.test c79441d88d23696fbec7b147dba98d42a04f523f
+F test/sysfault.test 503f72712b2b21cb80dc9899e53c2e39484d0313
 F test/table.test a59d985ca366e39b17b175f387f9d5db5a18d4e2
 F test/tableapi.test 2674633fa95d80da917571ebdd759a14d9819126
 F test/tclsqlite.test 37a61c2da7e3bfe3b8c1a2867199f6b860df5d43
@@ -952,11 +955,11 @@ F test/vtabF.test fd5ad376f5a34fe0891df1f3cddb4fe7c3eb077e
 F test/vtab_alter.test 9e374885248f69e251bdaacf480b04a197f125e5
 F test/vtab_err.test 0d4d8eb4def1d053ac7c5050df3024fd47a3fbd8
 F test/vtab_shared.test 82f463886e18d7f8395a4b6167c91815efe54839
-F test/wal.test a040047d7f2b9f34bc4d597964e5e7c09609c635
+F test/wal.test 62454b2cf00b311e9e65f898aad0fef536ed561a
 F test/wal2.test d4b470f13c87f6d8268b004380afa04c3c67cb90
 F test/wal3.test b22eb662bcbc148c5f6d956eaf94b047f7afe9c0
 F test/wal4.test 4744e155cd6299c6bd99d3eab1c82f77db9cdb3c
-F test/wal5.test f58ed4b8b542f71c7441da12fbd769d99b362437
+F test/wal5.test f4d0aee6a2cf09e326ed2459011d396b4fdf661a
 F test/wal6.test 2e3bc767d9c2ce35c47106148d43fcbd072a93b3
 F test/wal7.test 2ae8f427d240099cc4b2dfef63cff44e2a68a1bd
 F test/wal8.test b3ee739fe8f7586aaebdc2367f477ebcf3e3b034
@@ -1041,7 +1044,7 @@ F tool/vdbe-compress.tcl f12c884766bd14277f4fcedcae07078011717381
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
 F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
-P 5687e5ee7bafa00d2b353c3eda1e5dfb219cb185
+P e5b710849dd66673ba0e0d935b103cb29abfcc4b b2a72be9bab77f050bef75477a278a6294d3e854
-R b688b887865b3d8981922c40426941a0
+R 60af9b4d9e73e7757090b3abb77cbb41
 U drh
-Z 66f86621cb15eccea274cb5b5e71ec26
+Z d05e425b384f57133414b300483bca27

manifest.uuid

@@ -1 +1 @@
-e5b710849dd66673ba0e0d935b103cb29abfcc4b
+fff2be60779571c8fb89158db976ec3755e9a223

src/backup.c

@@ -397,7 +397,8 @@ int sqlite3_backup_step(sqlite3_backup *p, int nPage){
       const Pgno iSrcPg = p->iNext;                 /* Source page number */
       if( iSrcPg!=PENDING_BYTE_PAGE(p->pSrc->pBt) ){
         DbPage *pSrcPg;                             /* Source page object */
-        rc = sqlite3PagerGet(pSrcPager, iSrcPg, &pSrcPg);
+        rc = sqlite3PagerAcquire(pSrcPager, iSrcPg, &pSrcPg,
+                                 PAGER_ACQUIRE_READONLY);
         if( rc==SQLITE_OK ){
           rc = backupOnePage(p, iSrcPg, sqlite3PagerGetData(pSrcPg), 0);
           sqlite3PagerUnref(pSrcPg);

src/btree.c

@@ -1581,13 +1581,17 @@ static int btreeGetPage(
   BtShared *pBt,       /* The btree */
   Pgno pgno,           /* Number of the page to fetch */
   MemPage **ppPage,    /* Return the page in this parameter */
-  int noContent        /* Do not load page content if true */
+  int noContent,       /* Do not load page content if true */
+  int bReadonly        /* True if a read-only (mmap) page is ok */
 ){
   int rc;
   DbPage *pDbPage;
+  int flags = (noContent ? PAGER_ACQUIRE_NOCONTENT : 0) 
+            | (bReadonly ? PAGER_ACQUIRE_READONLY : 0);
 
+  assert( noContent==0 || bReadonly==0 );
   assert( sqlite3_mutex_held(pBt->mutex) );
-  rc = sqlite3PagerAcquire(pBt->pPager, pgno, (DbPage**)&pDbPage, noContent);
+  rc = sqlite3PagerAcquire(pBt->pPager, pgno, (DbPage**)&pDbPage, flags);
   if( rc ) return rc;
   *ppPage = btreePageFromDbPage(pDbPage, pgno, pBt);
   return SQLITE_OK;
@@ -1630,9 +1634,10 @@ u32 sqlite3BtreeLastPage(Btree *p){
 ** may remain unchanged, or it may be set to an invalid value.
 */
 static int getAndInitPage(
-  BtShared *pBt,          /* The database file */
+  BtShared *pBt,                  /* The database file */
-  Pgno pgno,           /* Number of the page to get */
+  Pgno pgno,                      /* Number of the page to get */
-  MemPage **ppPage     /* Write the page pointer here */
+  MemPage **ppPage,               /* Write the page pointer here */
+  int bReadonly                   /* True if a read-only (mmap) page is ok */
 ){
   int rc;
   assert( sqlite3_mutex_held(pBt->mutex) );
@@ -1640,7 +1645,7 @@ static int getAndInitPage(
   if( pgno>btreePagecount(pBt) ){
     rc = SQLITE_CORRUPT_BKPT;
   }else{
-    rc = btreeGetPage(pBt, pgno, ppPage, 0);
+    rc = btreeGetPage(pBt, pgno, ppPage, 0, bReadonly);
     if( rc==SQLITE_OK ){
       rc = btreeInitPage(*ppPage);
       if( rc!=SQLITE_OK ){
@@ -1871,6 +1876,7 @@ int sqlite3BtreeOpen(
     rc = sqlite3PagerOpen(pVfs, &pBt->pPager, zFilename,
                           EXTRA_SIZE, flags, vfsFlags, pageReinit);
     if( rc==SQLITE_OK ){
+      sqlite3PagerSetMmapLimit(pBt->pPager, db->mxMmap);
       rc = sqlite3PagerReadFileheader(pBt->pPager,sizeof(zDbHeader),zDbHeader);
     }
     if( rc!=SQLITE_OK ){
@@ -2137,6 +2143,19 @@ int sqlite3BtreeSetCacheSize(Btree *p, int mxPage){
   return SQLITE_OK;
 }
 
+/*
+** Change the limit on the amount of the database file that may be
+** memory mapped.
+*/
+int sqlite3BtreeSetMmapLimit(Btree *p, sqlite3_int64 mxMmap){
+  BtShared *pBt = p->pBt;
+  assert( sqlite3_mutex_held(p->db->mutex) );
+  sqlite3BtreeEnter(p);
+  sqlite3PagerSetMmapLimit(pBt->pPager, mxMmap);
+  sqlite3BtreeLeave(p);
+  return SQLITE_OK;
+}
+
 /*
 ** Change the way data is synced to disk in order to increase or decrease
 ** how well the database resists damage due to OS crashes and power
@@ -2362,7 +2381,7 @@ static int lockBtree(BtShared *pBt){
   assert( pBt->pPage1==0 );
   rc = sqlite3PagerSharedLock(pBt->pPager);
   if( rc!=SQLITE_OK ) return rc;
-  rc = btreeGetPage(pBt, 1, &pPage1, 0);
+  rc = btreeGetPage(pBt, 1, &pPage1, 0, 0);
   if( rc!=SQLITE_OK ) return rc;
 
   /* Do some checking to help insure the file we opened really is
@@ -2921,7 +2940,7 @@ static int relocatePage(
   ** iPtrPage.
   */
   if( eType!=PTRMAP_ROOTPAGE ){
-    rc = btreeGetPage(pBt, iPtrPage, &pPtrPage, 0);
+    rc = btreeGetPage(pBt, iPtrPage, &pPtrPage, 0, 0);
     if( rc!=SQLITE_OK ){
       return rc;
     }
@@ -3005,7 +3024,7 @@ static int incrVacuumStep(BtShared *pBt, Pgno nFin, Pgno iLastPg, int bCommit){
       u8 eMode = BTALLOC_ANY;   /* Mode parameter for allocateBtreePage() */
       Pgno iNear = 0;           /* nearby parameter for allocateBtreePage() */
 
-      rc = btreeGetPage(pBt, iLastPg, &pLastPg, 0);
+      rc = btreeGetPage(pBt, iLastPg, &pLastPg, 0, 0);
       if( rc!=SQLITE_OK ){
         return rc;
       }
@@ -3097,8 +3116,11 @@ int sqlite3BtreeIncrVacuum(Btree *p){
     if( nOrig<nFin ){
       rc = SQLITE_CORRUPT_BKPT;
     }else if( nFree>0 ){
-      invalidateAllOverflowCache(pBt);
+      rc = saveAllCursors(pBt, 0, 0);
-      rc = incrVacuumStep(pBt, nFin, nOrig, 0);
+      if( rc==SQLITE_OK ){
+        invalidateAllOverflowCache(pBt);
+        rc = incrVacuumStep(pBt, nFin, nOrig, 0);
+      }
       if( rc==SQLITE_OK ){
         rc = sqlite3PagerWrite(pBt->pPage1->pDbPage);
         put4byte(&pBt->pPage1->aData[28], pBt->nPage);
@@ -3146,7 +3168,9 @@ static int autoVacuumCommit(BtShared *pBt){
     nFree = get4byte(&pBt->pPage1->aData[36]);
     nFin = finalDbSize(pBt, nOrig, nFree);
     if( nFin>nOrig ) return SQLITE_CORRUPT_BKPT;
-
+    if( nFin<nOrig ){
+      rc = saveAllCursors(pBt, 0, 0);
+    }
     for(iFree=nOrig; iFree>nFin && rc==SQLITE_OK; iFree--){
       rc = incrVacuumStep(pBt, nFin, iFree, 1);
     }
@@ -3163,7 +3187,7 @@ static int autoVacuumCommit(BtShared *pBt){
     }
   }
 
-  assert( nRef==sqlite3PagerRefcount(pPager) );
+  assert( nRef>=sqlite3PagerRefcount(pPager) );
   return rc;
 }
 
@@ -3419,7 +3443,7 @@ int sqlite3BtreeRollback(Btree *p, int tripCode){
     /* The rollback may have destroyed the pPage1->aData value.  So
     ** call btreeGetPage() on page 1 again to make
     ** sure pPage1->aData is set correctly. */
-    if( btreeGetPage(pBt, 1, &pPage1, 0)==SQLITE_OK ){
+    if( btreeGetPage(pBt, 1, &pPage1, 0, 0)==SQLITE_OK ){
       int nPage = get4byte(28+(u8*)pPage1->aData);
       testcase( nPage==0 );
       if( nPage==0 ) sqlite3PagerPagecount(pBt->pPager, &nPage);
@@ -3853,7 +3877,7 @@ static int getOverflowPage(
 
   assert( next==0 || rc==SQLITE_DONE );
   if( rc==SQLITE_OK ){
-    rc = btreeGetPage(pBt, ovfl, &pPage, 0);
+    rc = btreeGetPage(pBt, ovfl, &pPage, 0, (ppPage==0));
     assert( rc==SQLITE_OK || pPage==0 );
     if( rc==SQLITE_OK ){
       next = get4byte(pPage->aData);
@@ -4074,7 +4098,9 @@ static int accessPayload(
 
         {
           DbPage *pDbPage;
-          rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage);
+          rc = sqlite3PagerAcquire(pBt->pPager, nextPage, &pDbPage,
+              (eOp==0 ? PAGER_ACQUIRE_READONLY : 0)
+          );
           if( rc==SQLITE_OK ){
             aPayload = sqlite3PagerGetData(pDbPage);
             nextPage = get4byte(aPayload);
@@ -4253,10 +4279,11 @@ static int moveToChild(BtCursor *pCur, u32 newPgno){
   assert( cursorHoldsMutex(pCur) );
   assert( pCur->eState==CURSOR_VALID );
   assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
+  assert( pCur->iPage>=0 );
   if( pCur->iPage>=(BTCURSOR_MAX_DEPTH-1) ){
     return SQLITE_CORRUPT_BKPT;
   }
-  rc = getAndInitPage(pBt, newPgno, &pNewPage);
+  rc = getAndInitPage(pBt, newPgno, &pNewPage, (pCur->wrFlag==0));
   if( rc ) return rc;
   pCur->apPage[i+1] = pNewPage;
   pCur->aiIdx[i+1] = 0;
@@ -4373,7 +4400,7 @@ static int moveToRoot(BtCursor *pCur){
     pCur->eState = CURSOR_INVALID;
     return SQLITE_OK;
   }else{
-    rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->apPage[0]);
+    rc = getAndInitPage(pBt, pCur->pgnoRoot, &pCur->apPage[0], pCur->wrFlag==0);
     if( rc!=SQLITE_OK ){
       pCur->eState = CURSOR_INVALID;
       return rc;
@@ -4987,7 +5014,7 @@ static int allocateBtreePage(
       if( iTrunk>mxPage ){
         rc = SQLITE_CORRUPT_BKPT;
       }else{
-        rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
+        rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0, 0);
       }
       if( rc ){
         pTrunk = 0;
@@ -5051,7 +5078,7 @@ static int allocateBtreePage(
             goto end_allocate_page;
           }
           testcase( iNewTrunk==mxPage );
-          rc = btreeGetPage(pBt, iNewTrunk, &pNewTrunk, 0);
+          rc = btreeGetPage(pBt, iNewTrunk, &pNewTrunk, 0, 0);
           if( rc!=SQLITE_OK ){
             goto end_allocate_page;
           }
@@ -5131,7 +5158,7 @@ static int allocateBtreePage(
           }
           put4byte(&aData[4], k-1);
           noContent = !btreeGetHasContent(pBt, *pPgno);
-          rc = btreeGetPage(pBt, *pPgno, ppPage, noContent);
+          rc = btreeGetPage(pBt, *pPgno, ppPage, noContent, 0);
           if( rc==SQLITE_OK ){
             rc = sqlite3PagerWrite((*ppPage)->pDbPage);
             if( rc!=SQLITE_OK ){
@@ -5179,7 +5206,7 @@ static int allocateBtreePage(
       MemPage *pPg = 0;
       TRACE(("ALLOCATE: %d from end of file (pointer-map page)\n", pBt->nPage));
       assert( pBt->nPage!=PENDING_BYTE_PAGE(pBt) );
-      rc = btreeGetPage(pBt, pBt->nPage, &pPg, bNoContent);
+      rc = btreeGetPage(pBt, pBt->nPage, &pPg, bNoContent, 0);
       if( rc==SQLITE_OK ){
         rc = sqlite3PagerWrite(pPg->pDbPage);
         releasePage(pPg);
@@ -5193,7 +5220,7 @@ static int allocateBtreePage(
     *pPgno = pBt->nPage;
 
     assert( *pPgno!=PENDING_BYTE_PAGE(pBt) );
-    rc = btreeGetPage(pBt, *pPgno, ppPage, bNoContent);
+    rc = btreeGetPage(pBt, *pPgno, ppPage, bNoContent, 0);
     if( rc ) return rc;
     rc = sqlite3PagerWrite((*ppPage)->pDbPage);
     if( rc!=SQLITE_OK ){
@@ -5261,7 +5288,7 @@ static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
     /* If the secure_delete option is enabled, then
     ** always fully overwrite deleted information with zeros.
     */
-    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0))!=0) )
+    if( (!pPage && ((rc = btreeGetPage(pBt, iPage, &pPage, 0, 0))!=0) )
      ||            ((rc = sqlite3PagerWrite(pPage->pDbPage))!=0)
     ){
       goto freepage_out;
@@ -5288,7 +5315,7 @@ static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
     u32 nLeaf;                /* Initial number of leaf cells on trunk page */
 
     iTrunk = get4byte(&pPage1->aData[32]);
-    rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0);
+    rc = btreeGetPage(pBt, iTrunk, &pTrunk, 0, 0);
     if( rc!=SQLITE_OK ){
       goto freepage_out;
     }
@@ -5334,7 +5361,7 @@ static int freePage2(BtShared *pBt, MemPage *pMemPage, Pgno iPage){
   ** first trunk in the free-list is full. Either way, the page being freed
   ** will become the new first trunk page in the free-list.
   */
-  if( pPage==0 && SQLITE_OK!=(rc = btreeGetPage(pBt, iPage, &pPage, 0)) ){
+  if( pPage==0 && SQLITE_OK!=(rc = btreeGetPage(pBt, iPage, &pPage, 0, 0)) ){
     goto freepage_out;
   }
   rc = sqlite3PagerWrite(pPage->pDbPage);
@@ -6135,7 +6162,7 @@ static int balance_nonroot(
   }
   pgno = get4byte(pRight);
   while( 1 ){
-    rc = getAndInitPage(pBt, pgno, &apOld[i]);
+    rc = getAndInitPage(pBt, pgno, &apOld[i], 0);
     if( rc ){
       memset(apOld, 0, (i+1)*sizeof(MemPage*));
       goto balance_cleanup;
@@ -7223,10 +7250,17 @@ static int btreeCreateTable(Btree *p, int *piTable, int createTabFlags){
       u8 eType = 0;
       Pgno iPtrPage = 0;
 
+      /* Save the positions of any open cursors. This is required in
+      ** case they are holding a reference to an xFetch reference
+      ** corresponding to page pgnoRoot.  */
+      rc = saveAllCursors(pBt, 0, 0);
       releasePage(pPageMove);
+      if( rc!=SQLITE_OK ){
+        return rc;
+      }
 
       /* Move the page currently at pgnoRoot to pgnoMove. */
-      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0, 0);
       if( rc!=SQLITE_OK ){
         return rc;
       }
@@ -7247,7 +7281,7 @@ static int btreeCreateTable(Btree *p, int *piTable, int createTabFlags){
       if( rc!=SQLITE_OK ){
         return rc;
       }
-      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0);
+      rc = btreeGetPage(pBt, pgnoRoot, &pRoot, 0, 0);
       if( rc!=SQLITE_OK ){
         return rc;
       }
@@ -7323,7 +7357,7 @@ static int clearDatabasePage(
     return SQLITE_CORRUPT_BKPT;
   }
 
-  rc = getAndInitPage(pBt, pgno, &pPage);
+  rc = getAndInitPage(pBt, pgno, &pPage, 0);
   if( rc ) return rc;
   for(i=0; i<pPage->nCell; i++){
     pCell = findCell(pPage, i);
@@ -7425,7 +7459,7 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
     return SQLITE_LOCKED_SHAREDCACHE;
   }
 
-  rc = btreeGetPage(pBt, (Pgno)iTable, &pPage, 0);
+  rc = btreeGetPage(pBt, (Pgno)iTable, &pPage, 0, 0);
   if( rc ) return rc;
   rc = sqlite3BtreeClearTable(p, iTable, 0);
   if( rc ){
@@ -7460,7 +7494,7 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
         */
         MemPage *pMove;
         releasePage(pPage);
-        rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
+        rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0, 0);
         if( rc!=SQLITE_OK ){
           return rc;
         }
@@ -7470,7 +7504,7 @@ static int btreeDropTable(Btree *p, Pgno iTable, int *piMoved){
           return rc;
         }
         pMove = 0;
-        rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0);
+        rc = btreeGetPage(pBt, maxRootPgno, &pMove, 0, 0);
         freePage(pMove, &rc);
         releasePage(pMove);
         if( rc!=SQLITE_OK ){
@@ -7882,7 +7916,7 @@ static int checkTreePage(
   usableSize = pBt->usableSize;
   if( iPage==0 ) return 0;
   if( checkRef(pCheck, iPage, zParentContext) ) return 0;
-  if( (rc = btreeGetPage(pBt, (Pgno)iPage, &pPage, 0))!=0 ){
+  if( (rc = btreeGetPage(pBt, (Pgno)iPage, &pPage, 0, 0))!=0 ){
     checkAppendMsg(pCheck, zContext,
        "unable to get the page. error code=%d", rc);
     return 0;
@@ -8354,6 +8388,17 @@ int sqlite3BtreePutData(BtCursor *pCsr, u32 offset, u32 amt, void *z){
     return SQLITE_ABORT;
   }
 
+  /* Save the positions of all other cursors open on this table. This is
+  ** required in case any of them are holding references to an xFetch
+  ** version of the b-tree page modified by the accessPayload call below.
+  **
+  ** Note that pCsr must be open on a BTREE_INTKEY table and saveCursorPosition()
+  ** and hence saveAllCursors() cannot fail on a BTREE_INTKEY table, hence
+  ** saveAllCursors can only return SQLITE_OK.
+  */
+  VVA_ONLY(rc =) saveAllCursors(pCsr->pBt, pCsr->pgnoRoot, pCsr);
+  assert( rc==SQLITE_OK );
+
   /* Check some assumptions: 
   **   (a) the cursor is open for writing,
   **   (b) there is a read/write transaction open,

src/btree.h

@@ -63,6 +63,7 @@ int sqlite3BtreeOpen(
 
 int sqlite3BtreeClose(Btree*);
 int sqlite3BtreeSetCacheSize(Btree*,int);
+int sqlite3BtreeSetMmapLimit(Btree*,sqlite3_int64);
 int sqlite3BtreeSetSafetyLevel(Btree*,int,int,int);
 int sqlite3BtreeSyncDisabled(Btree*);
 int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix);

src/ctime.c

@@ -57,6 +57,9 @@ static const char * const azCompileOpt[] = {
 #ifdef SQLITE_DEFAULT_LOCKING_MODE
   "DEFAULT_LOCKING_MODE=" CTIMEOPT_VAL(SQLITE_DEFAULT_LOCKING_MODE),
 #endif
+#ifdef SQLITE_DEFAULT_MMAP_LIMIT
+  "DEFAULT_MMAP_LIMIT=" CTIMEOPT_VAL(SQLITE_DEFAULT_MMAP_LIMIT),
+#endif
 #ifdef SQLITE_DISABLE_DIRSYNC
   "DISABLE_DIRSYNC",
 #endif

src/global.c

@@ -156,6 +156,7 @@ SQLITE_WSD struct Sqlite3Config sqlite3Config = {
    (void*)0,                  /* pHeap */
    0,                         /* nHeap */
    0, 0,                      /* mnHeap, mxHeap */
+   SQLITE_DEFAULT_MMAP_LIMIT, /* mxMmap */                       
    (void*)0,                  /* pScratch */
    0,                         /* szScratch */
    0,                         /* nScratch */

src/main.c

@@ -496,6 +496,13 @@ int sqlite3_config(int op, ...){
     }
 #endif
 
+    case SQLITE_CONFIG_MMAP_LIMIT: {
+      sqlite3_int64 mxMmap = va_arg(ap, sqlite3_int64);
+      if( mxMmap<0 ) mxMmap = SQLITE_DEFAULT_MMAP_LIMIT;
+      sqlite3GlobalConfig.mxMmap = mxMmap;
+      break;
+    }
+
     default: {
       rc = SQLITE_ERROR;
       break;
@@ -2316,6 +2323,7 @@ static int openDatabase(
   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
   db->autoCommit = 1;
   db->nextAutovac = -1;
+  db->mxMmap = sqlite3GlobalConfig.mxMmap;
   db->nextPagesize = 0;
   db->flags |= SQLITE_ShortColNames | SQLITE_AutoIndex | SQLITE_EnableTrigger
 #if SQLITE_DEFAULT_FILE_FORMAT<4

src/os.c

@@ -141,6 +141,14 @@ int sqlite3OsShmMap(
   return id->pMethods->xShmMap(id, iPage, pgsz, bExtend, pp);
 }
 
+int sqlite3OsFetch(sqlite3_file *id, i64 iOff, int iAmt, void **pp){
+  DO_OS_MALLOC_TEST(id);
+  return id->pMethods->xFetch(id, iOff, iAmt, pp);
+}
+int sqlite3OsUnfetch(sqlite3_file *id, i64 iOff, void *p){
+  return id->pMethods->xUnfetch(id, iOff, p);
+}
+
 /*
 ** The next group of routines are convenience wrappers around the
 ** VFS methods.

src/os.h

@@ -259,6 +259,8 @@ int sqlite3OsShmMap(sqlite3_file *,int,int,int,void volatile **);
 int sqlite3OsShmLock(sqlite3_file *id, int, int, int);
 void sqlite3OsShmBarrier(sqlite3_file *id);
 int sqlite3OsShmUnmap(sqlite3_file *id, int);
+int sqlite3OsFetch(sqlite3_file *id, i64, int, void **);
+int sqlite3OsUnfetch(sqlite3_file *, i64, void *);
 
 
 /* 

src/os_unix.c

@@ -225,6 +225,11 @@ struct unixFile {
   const char *zPath;                  /* Name of the file */
   unixShm *pShm;                      /* Shared memory segment information */
   int szChunk;                        /* Configured by FCNTL_CHUNK_SIZE */
+  int nFetchOut;                      /* Number of outstanding xFetch refs */
+  sqlite3_int64 mmapSize;             /* Usable size of mapping at pMapRegion */
+  sqlite3_int64 mmapOrigsize;         /* Actual size of mapping at pMapRegion */
+  sqlite3_int64 mmapLimit;            /* Configured FCNTL_MMAP_LIMIT value */
+  void *pMapRegion;                   /* Memory mapped region */
 #ifdef __QNXNTO__
   int sectorSize;                     /* Device sector size */
   int deviceCharacteristics;          /* Precomputed device characteristics */
@@ -249,7 +254,9 @@ struct unixFile {
   unsigned char transCntrChng;   /* True if the transaction counter changed */
   unsigned char dbUpdate;        /* True if any part of database file changed */
   unsigned char inNormalWrite;   /* True if in a normal write operation */
+
 #endif
+
 #ifdef SQLITE_TEST
   /* In test mode, increase the size of this structure a bit so that 
   ** it is larger than the struct CrashFile defined in test6.c.
@@ -306,6 +313,17 @@ struct unixFile {
 #define threadid 0
 #endif
 
+/*
+** HAVE_MREMAP defaults to true on Linux and false everywhere else.
+*/
+#if !defined(HAVE_MREMAP)
+# if defined(__linux__) && defined(_GNU_SOURCE)
+#  define HAVE_MREMAP 1
+# else
+#  define HAVE_MREMAP 0
+# endif
+#endif
+
 /*
 ** Different Unix systems declare open() in different ways.  Same use
 ** open(const char*,int,mode_t).  Others use open(const char*,int,...).
@@ -437,6 +455,19 @@ static struct unix_syscall {
   { "fchown",       (sqlite3_syscall_ptr)posixFchown,     0 },
 #define osFchown    ((int(*)(int,uid_t,gid_t))aSyscall[20].pCurrent)
 
+  { "mmap",       (sqlite3_syscall_ptr)mmap,     0 },
+#define osMmap ((void*(*)(void*,size_t,int,int,int,off_t))aSyscall[21].pCurrent)
+
+  { "munmap",       (sqlite3_syscall_ptr)munmap,          0 },
+#define osMunmap ((void*(*)(void*,size_t))aSyscall[22].pCurrent)
+
+#if HAVE_MREMAP
+  { "mremap",       (sqlite3_syscall_ptr)mremap,          0 },
+#else
+  { "mremap",       (sqlite3_syscall_ptr)0,               0 },
+#endif
+#define osMremap ((void*(*)(void*,size_t,size_t,int,...))aSyscall[23].pCurrent)
+
 }; /* End of the overrideable system calls */
 
 /*
@@ -1104,7 +1135,6 @@ static int unixLogErrorAtLine(
   zErr = strerror(iErrno);
 #endif
 
-  assert( errcode!=SQLITE_OK );
   if( zPath==0 ) zPath = "";
   sqlite3_log(errcode,
       "os_unix.c:%d: (%d) %s(%s) - %s",
@@ -1800,9 +1830,13 @@ end_unlock:
 ** the requested locking level, this routine is a no-op.
 */
 static int unixUnlock(sqlite3_file *id, int eFileLock){
+  assert( eFileLock==SHARED_LOCK || ((unixFile *)id)->nFetchOut==0 );
   return posixUnlock(id, eFileLock, 0);
 }
 
+static int unixMapfile(unixFile *pFd, i64 nByte);
+static void unixUnmapfile(unixFile *pFd);
+
 /*
 ** This function performs the parts of the "close file" operation 
 ** common to all locking schemes. It closes the directory and file
@@ -1815,6 +1849,7 @@ static int unixUnlock(sqlite3_file *id, int eFileLock){
 */
 static int closeUnixFile(sqlite3_file *id){
   unixFile *pFile = (unixFile*)id;
+  unixUnmapfile(pFile);
   if( pFile->h>=0 ){
     robust_close(pFile, pFile->h, __LINE__);
     pFile->h = -1;
@@ -3082,6 +3117,21 @@ static int unixRead(
   );
 #endif
 
+  /* Deal with as much of this read request as possible by transfering
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = pFile->mmapSize - offset;
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+
   got = seekAndRead(pFile, offset, pBuf, amt);
   if( got==amt ){
     return SQLITE_OK;
@@ -3186,6 +3236,21 @@ static int unixWrite(
   }
 #endif
 
+  /* Deal with as much of this write request as possible by transfering
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = pFile->mmapSize - offset;
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+
   while( amt>0 && (wrote = seekAndWrite(pFile, offset, pBuf, amt))>0 ){
     amt -= wrote;
     offset += wrote;
@@ -3468,6 +3533,14 @@ static int unixTruncate(sqlite3_file *id, i64 nByte){
     }
 #endif
 
+    /* If the file was just truncated to a size smaller than the currently
+    ** mapped region, reduce the effective mapping size as well. SQLite will
+    ** use read() and write() to access data beyond this point from now on.  
+    */
+    if( nByte<pFile->mmapSize ){
+      pFile->mmapSize = nByte;
+    }
+
     return SQLITE_OK;
   }
 }
@@ -3556,6 +3629,19 @@ static int fcntlSizeHint(unixFile *pFile, i64 nByte){
     }
   }
 
+  if( pFile->mmapLimit>0 && nByte>pFile->mmapSize ){
+    int rc;
+    if( pFile->szChunk<=0 ){
+      if( robust_ftruncate(pFile->h, nByte) ){
+        pFile->lastErrno = errno;
+        return unixLogError(SQLITE_IOERR_TRUNCATE, "ftruncate", pFile->zPath);
+      }
+    }
+
+    rc = unixMapfile(pFile, nByte);
+    return rc;
+  }
+
   return SQLITE_OK;
 }
 
@@ -3623,6 +3709,12 @@ static int unixFileControl(sqlite3_file *id, int op, void *pArg){
       }
       return SQLITE_OK;
     }
+    case SQLITE_FCNTL_MMAP_LIMIT: {
+      i64 newLimit = *(i64*)pArg;
+      *(i64*)pArg = pFile->mmapLimit;
+      if( newLimit>=0 ) pFile->mmapLimit = newLimit;
+      return SQLITE_OK;
+    }
 #ifdef SQLITE_DEBUG
     /* The pager calls this method to signal that it has done
     ** a rollback and that the database is therefore unchanged and
@@ -3935,7 +4027,7 @@ static void unixShmPurge(unixFile *pFd){
     sqlite3_mutex_free(p->mutex);
     for(i=0; i<p->nRegion; i++){
       if( p->h>=0 ){
-        munmap(p->apRegion[i], p->szRegion);
+        osMunmap(p->apRegion[i], p->szRegion);
       }else{
         sqlite3_free(p->apRegion[i]);
       }
@@ -4208,7 +4300,7 @@ static int unixShmMap(
     while(pShmNode->nRegion<=iRegion){
       void *pMem;
       if( pShmNode->h>=0 ){
-        pMem = mmap(0, szRegion,
+        pMem = osMmap(0, szRegion,
             pShmNode->isReadonly ? PROT_READ : PROT_READ|PROT_WRITE, 
             MAP_SHARED, pShmNode->h, szRegion*(i64)pShmNode->nRegion
         );
@@ -4425,6 +4517,223 @@ static int unixShmUnmap(
 # define unixShmUnmap   0
 #endif /* #ifndef SQLITE_OMIT_WAL */
 
+/*
+** If it is currently memory mapped, unmap file pFd.
+*/
+static void unixUnmapfile(unixFile *pFd){
+  assert( pFd->nFetchOut==0 );
+  if( pFd->pMapRegion ){
+    osMunmap(pFd->pMapRegion, pFd->mmapOrigsize);
+    pFd->pMapRegion = 0;
+    pFd->mmapSize = 0;
+    pFd->mmapOrigsize = 0;
+  }
+}
+
+/*
+** Return the system page size.
+*/
+static int unixGetPagesize(void){
+#if HAVE_MREMAP
+  return 512;
+#elif defined(_BSD_SOURCE)
+  return getpagesize();
+#else
+  return (int)sysconf(_SC_PAGESIZE);
+#endif
+}
+
+/*
+** Attempt to set the size of the memory mapping maintained by file 
+** descriptor pFd to nNew bytes. Any existing mapping is discarded.
+**
+** If successful, this function sets the following variables:
+**
+**       unixFile.pMapRegion
+**       unixFile.mmapSize
+**       unixFile.mmapOrigsize
+**
+** If unsuccessful, an error message is logged via sqlite3_log() and
+** the three variables above are zeroed. In this case SQLite should
+** continue accessing the database using the xRead() and xWrite()
+** methods.
+*/
+static void unixRemapfile(
+  unixFile *pFd,                  /* File descriptor object */
+  i64 nNew                        /* Required mapping size */
+){
+  const char *zErr = "mmap";
+  int h = pFd->h;                      /* File descriptor open on db file */
+  u8 *pOrig = (u8 *)pFd->pMapRegion;   /* Pointer to current file mapping */
+  i64 nOrig = pFd->mmapOrigsize;       /* Size of pOrig region in bytes */
+  u8 *pNew = 0;                        /* Location of new mapping */
+  int flags = PROT_READ;               /* Flags to pass to mmap() */
+
+  assert( pFd->nFetchOut==0 );
+  assert( nNew>pFd->mmapSize );
+  assert( nNew<=pFd->mmapLimit );
+  assert( nNew>0 );
+  assert( pFd->mmapOrigsize>=pFd->mmapSize );
+  assert( MAP_FAILED!=0 );
+
+  if( (pFd->ctrlFlags & UNIXFILE_RDONLY)==0 ) flags |= PROT_WRITE;
+
+  if( pOrig ){
+    const int szSyspage = unixGetPagesize();
+    i64 nReuse = (pFd->mmapSize & ~(szSyspage-1));
+    u8 *pReq = &pOrig[nReuse];
+
+    /* Unmap any pages of the existing mapping that cannot be reused. */
+    if( nReuse!=nOrig ){
+      osMunmap(pReq, nOrig-nReuse);
+    }
+
+#if HAVE_MREMAP
+    pNew = osMremap(pOrig, nReuse, nNew, MREMAP_MAYMOVE);
+    zErr = "mremap";
+#else
+    pNew = osMmap(pReq, nNew-nReuse, flags, MAP_SHARED, h, nReuse);
+    if( pNew!=MAP_FAILED ){
+      if( pNew!=pReq ){
+        osMunmap(pNew, nNew - nReuse);
+        pNew = 0;
+      }else{
+        pNew = pOrig;
+      }
+    }
+#endif
+
+    /* The attempt to extend the existing mapping failed. Free it. */
+    if( pNew==MAP_FAILED || pNew==0 ){
+      osMunmap(pOrig, nReuse);
+    }
+  }
+
+  /* If pNew is still NULL, try to create an entirely new mapping. */
+  if( pNew==0 ){
+    pNew = osMmap(0, nNew, flags, MAP_SHARED, h, 0);
+  }
+
+  if( pNew==MAP_FAILED ){
+    pNew = 0;
+    nNew = 0;
+    unixLogError(SQLITE_OK, zErr, pFd->zPath);
+
+    /* If the mmap() above failed, assume that all subsequent mmap() calls
+    ** will probably fail too. Fall back to using xRead/xWrite exclusively
+    ** in this case.  */
+    pFd->mmapLimit = 0;
+  }
+  pFd->pMapRegion = (void *)pNew;
+  pFd->mmapSize = pFd->mmapOrigsize = nNew;
+}
+
+/*
+** Memory map or remap the file opened by file-descriptor pFd (if the file
+** is already mapped, the existing mapping is replaced by the new). Or, if 
+** there already exists a mapping for this file, and there are still 
+** outstanding xFetch() references to it, this function is a no-op.
+**
+** If parameter nByte is non-negative, then it is the requested size of 
+** the mapping to create. Otherwise, if nByte is less than zero, then the 
+** requested size is the size of the file on disk. The actual size of the
+** created mapping is either the requested size or the value configured 
+** using SQLITE_FCNTL_MMAP_LIMIT, whichever is smaller.
+**
+** SQLITE_OK is returned if no error occurs (even if the mapping is not
+** recreated as a result of outstanding references) or an SQLite error
+** code otherwise.
+*/
+static int unixMapfile(unixFile *pFd, i64 nByte){
+  i64 nMap = nByte;
+  int rc;
+
+  assert( nMap>=0 || pFd->nFetchOut==0 );
+  if( pFd->nFetchOut>0 ) return SQLITE_OK;
+
+  if( nMap<0 ){
+    struct stat statbuf;          /* Low-level file information */
+    rc = osFstat(pFd->h, &statbuf);
+    if( rc!=SQLITE_OK ){
+      return SQLITE_IOERR_FSTAT;
+    }
+    nMap = statbuf.st_size;
+  }
+  if( nMap>pFd->mmapLimit ){
+    nMap = pFd->mmapLimit;
+  }
+
+  if( nMap!=pFd->mmapSize ){
+    if( nMap>0 ){
+      unixRemapfile(pFd, nMap);
+    }else{
+      unixUnmapfile(pFd);
+    }
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** If possible, return a pointer to a mapping of file fd starting at offset
+** iOff. The mapping must be valid for at least nAmt bytes.
+**
+** If such a pointer can be obtained, store it in *pp and return SQLITE_OK.
+** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK.
+** Finally, if an error does occur, return an SQLite error code. The final
+** value of *pp is undefined in this case.
+**
+** If this function does return a pointer, the caller must eventually 
+** release the reference by calling unixUnfetch().
+*/
+static int unixFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
+  unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
+  *pp = 0;
+
+  if( pFd->mmapLimit>0 ){
+    if( pFd->pMapRegion==0 ){
+      int rc = unixMapfile(pFd, -1);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    if( pFd->mmapSize >= iOff+nAmt ){
+      *pp = &((u8 *)pFd->pMapRegion)[iOff];
+      pFd->nFetchOut++;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** If the third argument is non-NULL, then this function releases a 
+** reference obtained by an earlier call to unixFetch(). The second
+** argument passed to this function must be the same as the corresponding
+** argument that was passed to the unixFetch() invocation. 
+**
+** Or, if the third argument is NULL, then this function is being called 
+** to inform the VFS layer that, according to POSIX, any existing mapping 
+** may now be invalid and should be unmapped.
+*/
+static int unixUnfetch(sqlite3_file *fd, i64 iOff, void *p){
+  unixFile *pFd = (unixFile *)fd;   /* The underlying database file */
+
+  /* If p==0 (unmap the entire file) then there must be no outstanding 
+  ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference),
+  ** then there must be at least one outstanding.  */
+  assert( (p==0)==(pFd->nFetchOut==0) );
+
+  /* If p!=0, it must match the iOff value. */
+  assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] );
+
+  if( p ){
+    pFd->nFetchOut--;
+  }else{
+    unixUnmapfile(pFd);
+  }
+
+  assert( pFd->nFetchOut>=0 );
+  return SQLITE_OK;
+}
+
 /*
 ** Here ends the implementation of all sqlite3_file methods.
 **
@@ -4483,7 +4792,9 @@ static const sqlite3_io_methods METHOD = {                                   \
    unixShmMap,                 /* xShmMap */                                 \
    unixShmLock,                /* xShmLock */                                \
    unixShmBarrier,             /* xShmBarrier */                             \
-   unixShmUnmap                /* xShmUnmap */                               \
+   unixShmUnmap,               /* xShmUnmap */                               \
+   unixFetch,                  /* xFetch */                                  \
+   unixUnfetch,                /* xUnfetch */                                \
 };                                                                           \
 static const sqlite3_io_methods *FINDER##Impl(const char *z, unixFile *p){   \
   UNUSED_PARAMETER(z); UNUSED_PARAMETER(p);                                  \
@@ -4500,7 +4811,7 @@ static const sqlite3_io_methods *(*const FINDER)(const char*,unixFile *p)    \
 IOMETHODS(
   posixIoFinder,            /* Finder function name */
   posixIoMethods,           /* sqlite3_io_methods object name */
-  2,                        /* shared memory is enabled */
+  3,                        /* shared memory and mmap are enabled */
   unixClose,                /* xClose method */
   unixLock,                 /* xLock method */
   unixUnlock,               /* xUnlock method */
@@ -4751,6 +5062,7 @@ static int fillInUnixFile(
   pNew->pVfs = pVfs;
   pNew->zPath = zFilename;
   pNew->ctrlFlags = (u8)ctrlFlags;
+  pNew->mmapLimit = sqlite3GlobalConfig.mxMmap;
   if( sqlite3_uri_boolean(((ctrlFlags & UNIXFILE_URI) ? zFilename : 0),
                            "psow", SQLITE_POWERSAFE_OVERWRITE) ){
     pNew->ctrlFlags |= UNIXFILE_PSOW;
@@ -6988,7 +7300,7 @@ int sqlite3_os_init(void){
 
   /* Double-check that the aSyscall[] array has been constructed
   ** correctly.  See ticket [bb3a86e890c8e96ab] */
-  assert( ArraySize(aSyscall)==21 );
+  assert( ArraySize(aSyscall)==24 );
 
   /* Register all VFSes defined in the aVfs[] array */
   for(i=0; i<(sizeof(aVfs)/sizeof(sqlite3_vfs)); i++){

src/os_win.c

@@ -150,11 +150,18 @@ struct winFile {
   winceLock local;        /* Locks obtained by this instance of winFile */
   winceLock *shared;      /* Global shared lock memory for the file  */
 #endif
+  int nFetchOut;               /* Number of outstanding xFetch references */
+  HANDLE hMap;                 /* Handle for accessing memory mapping */
+  void *pMapRegion;            /* Area memory mapped */
+  sqlite3_int64 mmapSize;      /* Usable size of mapped region */
+  sqlite3_int64 mmapOrigsize;  /* Actual size of mapped region */
+  sqlite3_int64 mmapLimit;     /* Configured FCNTL_MMAP_LIMIT value */
 };
 
 /*
 ** Allowed values for winFile.ctrlFlags
 */
+#define WINFILE_RDONLY          0x02   /* Connection is read only */
 #define WINFILE_PERSIST_WAL     0x04   /* Persistent WAL mode */
 #define WINFILE_PSOW            0x10   /* SQLITE_IOCAP_POWERSAFE_OVERWRITE */
 
@@ -2061,6 +2068,9 @@ static int seekWinFile(winFile *pFile, sqlite3_int64 iOffset){
 #endif
 }
 
+/* Forward references to VFS methods */
+static int winUnmapfile(winFile*);
+
 /*
 ** Close a file.
 **
@@ -2082,6 +2092,10 @@ static int winClose(sqlite3_file *id){
 #endif
   OSTRACE(("CLOSE %d\n", pFile->h));
   assert( pFile->h!=NULL && pFile->h!=INVALID_HANDLE_VALUE );
+
+  rc = winUnmapfile(pFile);
+  if( rc!=SQLITE_OK ) return rc;
+
   do{
     rc = osCloseHandle(pFile->h);
     /* SimulateIOError( rc=0; cnt=MX_CLOSE_ATTEMPT; ); */
@@ -2130,9 +2144,25 @@ static int winRead(
   int nRetry = 0;                 /* Number of retrys */
 
   assert( id!=0 );
+  assert( amt>0 );
   SimulateIOError(return SQLITE_IOERR_READ);
   OSTRACE(("READ %d lock=%d\n", pFile->h, pFile->locktype));
 
+  /* Deal with as much of this read request as possible by transfering
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = (int)(pFile->mmapSize - offset);
+      memcpy(pBuf, &((u8 *)(pFile->pMapRegion))[offset], nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+
 #if SQLITE_OS_WINCE
   if( seekWinFile(pFile, offset) ){
     return SQLITE_FULL;
@@ -2182,6 +2212,21 @@ static int winWrite(
 
   OSTRACE(("WRITE %d lock=%d\n", pFile->h, pFile->locktype));
 
+  /* Deal with as much of this write request as possible by transfering
+  ** data from the memory mapping using memcpy().  */
+  if( offset<pFile->mmapSize ){
+    if( offset+amt <= pFile->mmapSize ){
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, amt);
+      return SQLITE_OK;
+    }else{
+      int nCopy = (int)(pFile->mmapSize - offset);
+      memcpy(&((u8 *)(pFile->pMapRegion))[offset], pBuf, nCopy);
+      pBuf = &((u8 *)pBuf)[nCopy];
+      amt -= nCopy;
+      offset += nCopy;
+    }
+  }
+
 #if SQLITE_OS_WINCE
   rc = seekWinFile(pFile, offset);
   if( rc==0 ){
@@ -2249,6 +2294,7 @@ static int winWrite(
 static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
   winFile *pFile = (winFile*)id;  /* File handle object */
   int rc = SQLITE_OK;             /* Return code for this function */
+  DWORD lastErrno;
 
   assert( pFile );
 
@@ -2267,11 +2313,20 @@ static int winTruncate(sqlite3_file *id, sqlite3_int64 nByte){
   /* SetEndOfFile() returns non-zero when successful, or zero when it fails. */
   if( seekWinFile(pFile, nByte) ){
     rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
-             "winTruncate1", pFile->zPath);
+                     "winTruncate1", pFile->zPath);
-  }else if( 0==osSetEndOfFile(pFile->h) ){
+  }else if( 0==osSetEndOfFile(pFile->h) &&
-    pFile->lastErrno = osGetLastError();
+            ((lastErrno = osGetLastError())!=ERROR_USER_MAPPED_FILE) ){
+    pFile->lastErrno = lastErrno;
     rc = winLogError(SQLITE_IOERR_TRUNCATE, pFile->lastErrno,
-             "winTruncate2", pFile->zPath);
+                     "winTruncate2", pFile->zPath);
+  }
+
+  /* If the file was truncated to a size smaller than the currently
+  ** mapped region, reduce the effective mapping size as well. SQLite will
+  ** use read() and write() to access data beyond this point from now on.
+  */
+  if( pFile->pMapRegion && nByte<pFile->mmapSize ){
+    pFile->mmapSize = nByte;
   }
 
   OSTRACE(("TRUNCATE %d %lld %s\n", pFile->h, nByte, rc ? "failed" : "ok"));
@@ -2781,6 +2836,12 @@ static int winFileControl(sqlite3_file *id, int op, void *pArg){
       }
       return SQLITE_OK;
     }
+    case SQLITE_FCNTL_MMAP_LIMIT: {
+      i64 newLimit = *(i64*)pArg;
+      *(i64*)pArg = pFile->mmapLimit;
+      if( newLimit>=0 ) pFile->mmapLimit = newLimit;
+      return SQLITE_OK;
+    }
   }
   return SQLITE_NOTFOUND;
 }
@@ -3451,6 +3512,184 @@ shmpage_out:
 # define winShmUnmap   0
 #endif /* #ifndef SQLITE_OMIT_WAL */
 
+/*
+** Cleans up the mapped region of the specified file, if any.
+*/
+static int winUnmapfile(winFile *pFile){
+  assert( pFile!=0 );
+  if( pFile->pMapRegion ){
+    if( !osUnmapViewOfFile(pFile->pMapRegion) ){
+      pFile->lastErrno = osGetLastError();
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winUnmap1", pFile->zPath);
+    }
+    pFile->pMapRegion = 0;
+    pFile->mmapSize = 0;
+    pFile->mmapOrigsize = 0;
+  }
+  if( pFile->hMap!=NULL ){
+    if( !osCloseHandle(pFile->hMap) ){
+      pFile->lastErrno = osGetLastError();
+      return winLogError(SQLITE_IOERR_MMAP, pFile->lastErrno,
+                         "winUnmap2", pFile->zPath);
+    }
+    pFile->hMap = NULL;
+  }
+  return SQLITE_OK;
+}
+
+/*
+** Memory map or remap the file opened by file-descriptor pFd (if the file
+** is already mapped, the existing mapping is replaced by the new). Or, if 
+** there already exists a mapping for this file, and there are still 
+** outstanding xFetch() references to it, this function is a no-op.
+**
+** If parameter nByte is non-negative, then it is the requested size of 
+** the mapping to create. Otherwise, if nByte is less than zero, then the 
+** requested size is the size of the file on disk. The actual size of the
+** created mapping is either the requested size or the value configured 
+** using SQLITE_FCNTL_MMAP_LIMIT, whichever is smaller.
+**
+** SQLITE_OK is returned if no error occurs (even if the mapping is not
+** recreated as a result of outstanding references) or an SQLite error
+** code otherwise.
+*/
+static int winMapfile(winFile *pFd, sqlite3_int64 nByte){
+  sqlite3_int64 nMap = nByte;
+  int rc;
+
+  assert( nMap>=0 || pFd->nFetchOut==0 );
+  if( pFd->nFetchOut>0 ) return SQLITE_OK;
+
+  if( nMap<0 ){
+    rc = winFileSize((sqlite3_file*)pFd, &nMap);
+    if( rc ){
+      return SQLITE_IOERR_FSTAT;
+    }
+  }
+  if( nMap>pFd->mmapLimit ){
+    nMap = pFd->mmapLimit;
+  }
+  nMap &= ~(sqlite3_int64)(winSysInfo.dwPageSize - 1);
+ 
+  if( nMap==0 && pFd->mmapSize>0 ){
+    winUnmapfile(pFd);
+  }
+  if( nMap!=pFd->mmapSize ){
+    void *pNew = 0;
+    DWORD protect = PAGE_READONLY;
+    DWORD flags = FILE_MAP_READ;
+
+    winUnmapfile(pFd);
+    if( (pFd->ctrlFlags & WINFILE_RDONLY)==0 ){
+      protect = PAGE_READWRITE;
+      flags |= FILE_MAP_WRITE;
+    }
+#if SQLITE_OS_WINRT
+    pFd->hMap = osCreateFileMappingFromApp(pFd->h, NULL, protect, nMap, NULL);
+#elif defined(SQLITE_WIN32_HAS_WIDE)
+    pFd->hMap = osCreateFileMappingW(pFd->h, NULL, protect,
+                                (DWORD)((nMap>>32) & 0xffffffff),
+                                (DWORD)(nMap & 0xffffffff), NULL);
+#elif defined(SQLITE_WIN32_HAS_ANSI)
+    pFd->hMap = osCreateFileMappingA(pFd->h, NULL, protect,
+                                (DWORD)((nMap>>32) & 0xffffffff),
+                                (DWORD)(nMap & 0xffffffff), NULL);
+#endif
+    if( pFd->hMap==NULL ){
+      pFd->lastErrno = osGetLastError();
+      rc = winLogError(SQLITE_IOERR_MMAP, pFd->lastErrno,
+                       "winMapfile", pFd->zPath);
+      /* Log the error, but continue normal operation using xRead/xWrite */
+      return SQLITE_OK;
+    }
+    assert( (nMap % winSysInfo.dwPageSize)==0 );
+#if SQLITE_OS_WINRT
+    pNew = osMapViewOfFileFromApp(pFd->hMap, flags, 0, nMap);
+#else
+    assert( sizeof(SIZE_T)==sizeof(sqlite3_int64) || nMap<=0xffffffff );
+    pNew = osMapViewOfFile(pFd->hMap, flags, 0, 0, (SIZE_T)nMap);
+#endif
+    if( pNew==NULL ){
+      osCloseHandle(pFd->hMap);
+      pFd->hMap = NULL;
+      pFd->lastErrno = osGetLastError();
+      winLogError(SQLITE_IOERR_MMAP, pFd->lastErrno,
+                  "winMapfile", pFd->zPath);
+      return SQLITE_OK;
+    }
+    pFd->pMapRegion = pNew;
+    pFd->mmapSize = nMap;
+    pFd->mmapOrigsize = nMap;
+  }
+
+  return SQLITE_OK;
+}
+
+/*
+** If possible, return a pointer to a mapping of file fd starting at offset
+** iOff. The mapping must be valid for at least nAmt bytes.
+**
+** If such a pointer can be obtained, store it in *pp and return SQLITE_OK.
+** Or, if one cannot but no error occurs, set *pp to 0 and return SQLITE_OK.
+** Finally, if an error does occur, return an SQLite error code. The final
+** value of *pp is undefined in this case.
+**
+** If this function does return a pointer, the caller must eventually 
+** release the reference by calling unixUnfetch().
+*/
+static int winFetch(sqlite3_file *fd, i64 iOff, int nAmt, void **pp){
+  winFile *pFd = (winFile*)fd;   /* The underlying database file */
+  *pp = 0;
+
+  if( pFd->mmapLimit>0 ){
+    if( pFd->pMapRegion==0 ){
+      int rc = winMapfile(pFd, -1);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    if( pFd->mmapSize >= iOff+nAmt ){
+      *pp = &((u8 *)pFd->pMapRegion)[iOff];
+      pFd->nFetchOut++;
+    }
+  }
+  return SQLITE_OK;
+}
+
+/*
+** If the third argument is non-NULL, then this function releases a 
+** reference obtained by an earlier call to unixFetch(). The second
+** argument passed to this function must be the same as the corresponding
+** argument that was passed to the unixFetch() invocation. 
+**
+** Or, if the third argument is NULL, then this function is being called 
+** to inform the VFS layer that, according to POSIX, any existing mapping 
+** may now be invalid and should be unmapped.
+*/
+static int winUnfetch(sqlite3_file *fd, i64 iOff, void *p){
+  winFile *pFd = (winFile*)fd;   /* The underlying database file */
+
+  /* If p==0 (unmap the entire file) then there must be no outstanding 
+  ** xFetch references. Or, if p!=0 (meaning it is an xFetch reference),
+  ** then there must be at least one outstanding.  */
+  assert( (p==0)==(pFd->nFetchOut==0) );
+
+  /* If p!=0, it must match the iOff value. */
+  assert( p==0 || p==&((u8 *)pFd->pMapRegion)[iOff] );
+
+  if( p ){
+    pFd->nFetchOut--;
+  }else{
+    /* FIXME:  If Windows truly always prevents truncating or deleting a
+    ** file while a mapping is held, then the following winUnmapfile() call
+    ** is unnecessary can can be omitted - potentially improving
+    ** performance.  */
+    winUnmapfile(pFd);
+  }
+
+  assert( pFd->nFetchOut>=0 );
+  return SQLITE_OK;
+}
+
 /*
 ** Here ends the implementation of all sqlite3_file methods.
 **
@@ -3462,7 +3701,7 @@ shmpage_out:
 ** sqlite3_file for win32.
 */
 static const sqlite3_io_methods winIoMethod = {
-  2,                              /* iVersion */
+  3,                              /* iVersion */
   winClose,                       /* xClose */
   winRead,                        /* xRead */
   winWrite,                       /* xWrite */
@@ -3478,7 +3717,9 @@ static const sqlite3_io_methods winIoMethod = {
   winShmMap,                      /* xShmMap */
   winShmLock,                     /* xShmLock */
   winShmBarrier,                  /* xShmBarrier */
-  winShmUnmap                     /* xShmUnmap */
+  winShmUnmap,                    /* xShmUnmap */
+  winFetch,                       /* xFetch */
+  winUnfetch                      /* xUnfetch */
 };
 
 /****************************************************************************
@@ -3654,9 +3895,7 @@ static int winOpen(
   int isExclusive  = (flags & SQLITE_OPEN_EXCLUSIVE);
   int isDelete     = (flags & SQLITE_OPEN_DELETEONCLOSE);
   int isCreate     = (flags & SQLITE_OPEN_CREATE);
-#ifndef NDEBUG
   int isReadonly   = (flags & SQLITE_OPEN_READONLY);
-#endif
   int isReadWrite  = (flags & SQLITE_OPEN_READWRITE);
 
 #ifndef NDEBUG
@@ -3867,11 +4106,19 @@ static int winOpen(
   pFile->pMethod = &winIoMethod;
   pFile->pVfs = pVfs;
   pFile->h = h;
+  if( isReadonly ){
+    pFile->ctrlFlags |= WINFILE_RDONLY;
+  }
   if( sqlite3_uri_boolean(zName, "psow", SQLITE_POWERSAFE_OVERWRITE) ){
     pFile->ctrlFlags |= WINFILE_PSOW;
   }
   pFile->lastErrno = NO_ERROR;
   pFile->zPath = zName;
+  pFile->hMap = NULL;
+  pFile->pMapRegion = 0;
+  pFile->mmapSize = 0;
+  pFile->mmapOrigsize = 0;
+  pFile->mmapLimit = sqlite3GlobalConfig.mxMmap;
 
   OpenCounter(+1);
   return rc;
@@ -4500,7 +4747,6 @@ int sqlite3_os_init(void){
   ** correctly.  See ticket [bb3a86e890c8e96ab] */
   assert( ArraySize(aSyscall)==74 );
 
-#ifndef SQLITE_OMIT_WAL
   /* get memory map allocation granularity */
   memset(&winSysInfo, 0, sizeof(SYSTEM_INFO));
 #if SQLITE_OS_WINRT
@@ -4508,8 +4754,8 @@ int sqlite3_os_init(void){
 #else
   osGetSystemInfo(&winSysInfo);
 #endif
-  assert(winSysInfo.dwAllocationGranularity > 0);
+  assert( winSysInfo.dwAllocationGranularity>0 );
-#endif
+  assert( winSysInfo.dwPageSize>0 );
 
   sqlite3_vfs_register(&winVfs, 1);
   return SQLITE_OK; 

src/pager.c

@@ -655,6 +655,11 @@ struct Pager {
   PagerSavepoint *aSavepoint; /* Array of active savepoints */
   int nSavepoint;             /* Number of elements in aSavepoint[] */
   char dbFileVers[16];        /* Changes whenever database file changes */
+
+  u8 bUseFetch;               /* True to use xFetch() */
+  int nMmapOut;               /* Number of mmap pages currently outstanding */
+  sqlite3_int64 mxMmap;       /* Desired maximum mmap size */
+  PgHdr *pMmapFreelist;       /* List of free mmap page headers (pDirty) */
   /*
   ** End of the routinely-changing class members
   ***************************************************************************/
@@ -2252,7 +2257,7 @@ static int pager_playback_one_page(
     i64 ofst = (pgno-1)*(i64)pPager->pageSize;
     testcase( !isSavepnt && pPg!=0 && (pPg->flags&PGHDR_NEED_SYNC)!=0 );
     assert( !pagerUseWal(pPager) );
-    rc = sqlite3OsWrite(pPager->fd, (u8*)aData, pPager->pageSize, ofst);
+    rc = sqlite3OsWrite(pPager->fd, (u8 *)aData, pPager->pageSize, ofst);
     if( pgno>pPager->dbFileSize ){
       pPager->dbFileSize = pgno;
     }
@@ -2834,11 +2839,10 @@ end_playback:
 ** If an IO error occurs, then the IO error is returned to the caller.
 ** Otherwise, SQLITE_OK is returned.
 */
-static int readDbPage(PgHdr *pPg){
+static int readDbPage(PgHdr *pPg, u32 iFrame){
   Pager *pPager = pPg->pPager; /* Pager object associated with page pPg */
   Pgno pgno = pPg->pgno;       /* Page number to read */
   int rc = SQLITE_OK;          /* Return code */
-  int isInWal = 0;             /* True if page is in log file */
   int pgsz = pPager->pageSize; /* Number of bytes to read */
 
   assert( pPager->eState>=PAGER_READER && !MEMDB );
@@ -2850,11 +2854,10 @@ static int readDbPage(PgHdr *pPg){
     return SQLITE_OK;
   }
 
-  if( pagerUseWal(pPager) ){
+  if( iFrame ){
     /* Try to pull the page from the write-ahead log. */
-    rc = sqlite3WalRead(pPager->pWal, pgno, &isInWal, pgsz, pPg->pData);
+    rc = sqlite3WalReadFrame(pPager->pWal, iFrame, pgsz, pPg->pData);
-  }
+  }else{
-  if( rc==SQLITE_OK && !isInWal ){
     i64 iOffset = (pgno-1)*(i64)pPager->pageSize;
     rc = sqlite3OsRead(pPager->fd, pPg->pData, pgsz, iOffset);
     if( rc==SQLITE_IOERR_SHORT_READ ){
@@ -2933,12 +2936,17 @@ static int pagerUndoCallback(void *pCtx, Pgno iPg){
   Pager *pPager = (Pager *)pCtx;
   PgHdr *pPg;
 
+  assert( pagerUseWal(pPager) );
   pPg = sqlite3PagerLookup(pPager, iPg);
   if( pPg ){
     if( sqlite3PcachePageRefcount(pPg)==1 ){
       sqlite3PcacheDrop(pPg);
     }else{
-      rc = readDbPage(pPg);
+      u32 iFrame = 0;
+      rc = sqlite3WalFindFrame(pPager->pWal, pPg->pgno, &iFrame);
+      if( rc==SQLITE_OK ){
+        rc = readDbPage(pPg, iFrame);
+      }
       if( rc==SQLITE_OK ){
         pPager->xReiniter(pPg);
       }
@@ -3082,6 +3090,7 @@ static int pagerBeginReadTransaction(Pager *pPager){
   rc = sqlite3WalBeginReadTransaction(pPager->pWal, &changed);
   if( rc!=SQLITE_OK || changed ){
     pager_reset(pPager);
+    if( pPager->bUseFetch ) sqlite3OsUnfetch(pPager->fd, 0, 0);
   }
 
   return rc;
@@ -3343,6 +3352,27 @@ void sqlite3PagerSetCachesize(Pager *pPager, int mxPage){
   sqlite3PcacheSetCachesize(pPager->pPCache, mxPage);
 }
 
+/*
+** Invoke SQLITE_FCNTL_MMAP_LIMIT based on the current value of mxMmap.
+*/
+static void pagerFixMaplimit(Pager *pPager){
+  sqlite3_file *fd = pPager->fd;
+  if( isOpen(fd) ){
+    sqlite3_int64 mx;
+    pPager->bUseFetch = (fd->pMethods->iVersion>=3) && pPager->mxMmap>0;
+    mx = pPager->mxMmap;
+    sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_MMAP_LIMIT, &mx);
+  }
+}
+
+/*
+** Change the maximum size of any memory mapping made of the database file.
+*/
+void sqlite3PagerSetMmapLimit(Pager *pPager, sqlite3_int64 mxMmap){
+  pPager->mxMmap = mxMmap;
+  pagerFixMaplimit(pPager);
+}
+
 /*
 ** Free as much memory as possible from the pager.
 */
@@ -3578,6 +3608,7 @@ int sqlite3PagerSetPagesize(Pager *pPager, u32 *pPageSize, int nReserve){
     assert( nReserve>=0 && nReserve<1000 );
     pPager->nReserve = (i16)nReserve;
     pagerReportSize(pPager);
+    pagerFixMaplimit(pPager);
   }
   return rc;
 }
@@ -3803,6 +3834,81 @@ static int pagerSyncHotJournal(Pager *pPager){
   return rc;
 }
 
+/*
+** Obtain a reference to a memory mapped page object for page number pgno. 
+** The new object will use the pointer pData, obtained from xFetch().
+** If successful, set *ppPage to point to the new page reference
+** and return SQLITE_OK. Otherwise, return an SQLite error code and set
+** *ppPage to zero.
+**
+** Page references obtained by calling this function should be released
+** by calling pagerReleaseMapPage().
+*/
+static int pagerAcquireMapPage(
+  Pager *pPager,                  /* Pager object */
+  Pgno pgno,                      /* Page number */
+  void *pData,                    /* xFetch()'d data for this page */
+  PgHdr **ppPage                  /* OUT: Acquired page object */
+){
+  PgHdr *p;                       /* Memory mapped page to return */
+
+  if( pPager->pMmapFreelist ){
+    *ppPage = p = pPager->pMmapFreelist;
+    pPager->pMmapFreelist = p->pDirty;
+    p->pDirty = 0;
+    memset(p->pExtra, 0, pPager->nExtra);
+  }else{
+    *ppPage = p = (PgHdr *)sqlite3MallocZero(sizeof(PgHdr) + pPager->nExtra);
+    if( p==0 ){
+      sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1) * pPager->pageSize, pData);
+      return SQLITE_NOMEM;
+    }
+    p->pExtra = (void *)&p[1];
+    p->flags = PGHDR_MMAP;
+    p->nRef = 1;
+    p->pPager = pPager;
+  }
+
+  assert( p->pExtra==(void *)&p[1] );
+  assert( p->pPage==0 );
+  assert( p->flags==PGHDR_MMAP );
+  assert( p->pPager==pPager );
+  assert( p->nRef==1 );
+
+  p->pgno = pgno;
+  p->pData = pData;
+  pPager->nMmapOut++;
+
+  return SQLITE_OK;
+}
+
+/*
+** Release a reference to page pPg. pPg must have been returned by an 
+** earlier call to pagerAcquireMapPage().
+*/
+static void pagerReleaseMapPage(PgHdr *pPg){
+  Pager *pPager = pPg->pPager;
+  pPager->nMmapOut--;
+  pPg->pDirty = pPager->pMmapFreelist;
+  pPager->pMmapFreelist = pPg;
+
+  assert( pPager->fd->pMethods->iVersion>=3 );
+  sqlite3OsUnfetch(pPager->fd, (i64)(pPg->pgno-1)*pPager->pageSize, pPg->pData);
+}
+
+/*
+** Free all PgHdr objects stored in the Pager.pMmapFreelist list.
+*/
+static void pagerFreeMapHdrs(Pager *pPager){
+  PgHdr *p;
+  PgHdr *pNext;
+  for(p=pPager->pMmapFreelist; p; p=pNext){
+    pNext = p->pDirty;
+    sqlite3_free(p);
+  }
+}
+
+
 /*
 ** Shutdown the page cache.  Free all memory and close all files.
 **
@@ -3823,6 +3929,7 @@ int sqlite3PagerClose(Pager *pPager){
   assert( assert_pager_state(pPager) );
   disable_simulated_io_errors();
   sqlite3BeginBenignMalloc();
+  pagerFreeMapHdrs(pPager);
   /* pPager->errCode = 0; */
   pPager->exclusiveMode = 0;
 #ifndef SQLITE_OMIT_WAL
@@ -4084,7 +4191,9 @@ static int pager_write_pagelist(Pager *pPager, PgHdr *pList){
   ** file size will be.
   */
   assert( rc!=SQLITE_OK || isOpen(pPager->fd) );
-  if( rc==SQLITE_OK && pPager->dbSize>pPager->dbHintSize ){
+  if( rc==SQLITE_OK 
+   && (pList->pDirty ? pPager->dbSize : pList->pgno+1)>pPager->dbHintSize 
+  ){
     sqlite3_int64 szFile = pPager->pageSize * (sqlite3_int64)pPager->dbSize;
     sqlite3OsFileControlHint(pPager->fd, SQLITE_FCNTL_SIZE_HINT, &szFile);
     pPager->dbHintSize = pPager->dbSize;
@@ -4638,6 +4747,7 @@ int sqlite3PagerOpen(
   /* pPager->pBusyHandlerArg = 0; */
   pPager->xReiniter = xReinit;
   /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
+  /* pPager->mxMmap = SQLITE_DEFAULT_MMAP_LIMIT // will be set by btree.c */
 
   *ppPager = pPager;
   return SQLITE_OK;
@@ -4929,9 +5039,11 @@ int sqlite3PagerSharedLock(Pager *pPager){
       );
     }
 
-    if( !pPager->tempFile 
+    if( !pPager->tempFile && (
-     && (pPager->pBackup || sqlite3PcachePagecount(pPager->pPCache)>0) 
+        pPager->pBackup 
-    ){
+     || sqlite3PcachePagecount(pPager->pPCache)>0 
+     || pPager->bUseFetch
+    )){
       /* The shared-lock has just been acquired on the database file
       ** and there are already pages in the cache (from a previous
       ** read or write transaction).  Check to see if the database
@@ -4957,7 +5069,7 @@ int sqlite3PagerSharedLock(Pager *pPager){
       if( nPage>0 ){
         IOTRACE(("CKVERS %p %d\n", pPager, sizeof(dbFileVers)));
         rc = sqlite3OsRead(pPager->fd, &dbFileVers, sizeof(dbFileVers), 24);
-        if( rc!=SQLITE_OK ){
+        if( rc!=SQLITE_OK && rc!=SQLITE_IOERR_SHORT_READ ){
           goto failed;
         }
       }else{
@@ -4966,6 +5078,16 @@ int sqlite3PagerSharedLock(Pager *pPager){
 
       if( memcmp(pPager->dbFileVers, dbFileVers, sizeof(dbFileVers))!=0 ){
         pager_reset(pPager);
+
+        /* Unmap the database file. It is possible that external processes
+        ** may have truncated the database file and then extended it back
+        ** to its original size while this process was not holding a lock.
+        ** In this case there may exist a Pager.pMap mapping that appears
+        ** to be the right size but is not actually valid. Avoid this
+        ** possibility by unmapping the db here. */
+        if( pPager->bUseFetch ){
+          sqlite3OsUnfetch(pPager->fd, 0, 0);
+        }
       }
     }
 
@@ -5007,7 +5129,7 @@ int sqlite3PagerSharedLock(Pager *pPager){
 ** nothing to rollback, so this routine is a no-op.
 */ 
 static void pagerUnlockIfUnused(Pager *pPager){
-  if( (sqlite3PcacheRefCount(pPager->pPCache)==0) ){
+  if( pPager->nMmapOut==0 && (sqlite3PcacheRefCount(pPager->pPCache)==0) ){
     pagerUnlockAndRollback(pPager);
   }
 }
@@ -5066,13 +5188,24 @@ int sqlite3PagerAcquire(
   Pager *pPager,      /* The pager open on the database file */
   Pgno pgno,          /* Page number to fetch */
   DbPage **ppPage,    /* Write a pointer to the page here */
-  int noContent       /* Do not bother reading content from disk if true */
+  int flags           /* PAGER_ACQUIRE_XXX flags */
 ){
-  int rc;
+  int rc = SQLITE_OK;
-  PgHdr *pPg;
+  PgHdr *pPg = 0;
+  u32 iFrame = 0;                 /* Frame to read from WAL file */
+  const int noContent = (flags & PAGER_ACQUIRE_NOCONTENT);
+
+  /* It is acceptable to use a read-only (mmap) page for any page except
+  ** page 1 if there is no write-transaction open or the ACQUIRE_READONLY
+  ** flag was specified by the caller. And so long as the db is not a 
+  ** temporary or in-memory database.  */
+  const int bMmapOk = (pgno!=1 && pPager->bUseFetch
+   && (pPager->eState==PAGER_READER || (flags & PAGER_ACQUIRE_READONLY))
+  );
 
   assert( pPager->eState>=PAGER_READER );
   assert( assert_pager_state(pPager) );
+  assert( noContent==0 || bMmapOk==0 );
 
   if( pgno==0 ){
     return SQLITE_CORRUPT_BKPT;
@@ -5083,6 +5216,39 @@ int sqlite3PagerAcquire(
   if( pPager->errCode!=SQLITE_OK ){
     rc = pPager->errCode;
   }else{
+
+    if( bMmapOk && pagerUseWal(pPager) ){
+      rc = sqlite3WalFindFrame(pPager->pWal, pgno, &iFrame);
+      if( rc!=SQLITE_OK ) goto pager_acquire_err;
+    }
+
+    if( iFrame==0 && bMmapOk ){
+      void *pData = 0;
+
+      rc = sqlite3OsFetch(pPager->fd, 
+          (i64)(pgno-1) * pPager->pageSize, pPager->pageSize, &pData
+      );
+
+      if( rc==SQLITE_OK && pData ){
+        if( pPager->eState>PAGER_READER ){
+          (void)sqlite3PcacheFetch(pPager->pPCache, pgno, 0, &pPg);
+        }
+        if( pPg==0 ){
+          rc = pagerAcquireMapPage(pPager, pgno, pData, &pPg);
+        }else{
+          sqlite3OsUnfetch(pPager->fd, (i64)(pgno-1)*pPager->pageSize, pData);
+        }
+        if( pPg ){
+          assert( rc==SQLITE_OK );
+          *ppPage = pPg;
+          return SQLITE_OK;
+        }
+      }
+      if( rc!=SQLITE_OK ){
+        goto pager_acquire_err;
+      }
+    }
+
     rc = sqlite3PcacheFetch(pPager->pPCache, pgno, 1, ppPage);
   }
 
@@ -5141,9 +5307,13 @@ int sqlite3PagerAcquire(
       memset(pPg->pData, 0, pPager->pageSize);
       IOTRACE(("ZERO %p %d\n", pPager, pgno));
     }else{
+      if( pagerUseWal(pPager) && bMmapOk==0 ){
+        rc = sqlite3WalFindFrame(pPager->pWal, pgno, &iFrame);
+        if( rc!=SQLITE_OK ) goto pager_acquire_err;
+      }
       assert( pPg->pPager==pPager );
       pPager->aStat[PAGER_STAT_MISS]++;
-      rc = readDbPage(pPg);
+      rc = readDbPage(pPg, iFrame);
       if( rc!=SQLITE_OK ){
         goto pager_acquire_err;
       }
@@ -5196,7 +5366,11 @@ DbPage *sqlite3PagerLookup(Pager *pPager, Pgno pgno){
 void sqlite3PagerUnref(DbPage *pPg){
   if( pPg ){
     Pager *pPager = pPg->pPager;
-    sqlite3PcacheRelease(pPg);
+    if( pPg->flags & PGHDR_MMAP ){
+      pagerReleaseMapPage(pPg);
+    }else{
+      sqlite3PcacheRelease(pPg);
+    }
     pagerUnlockIfUnused(pPager);
   }
 }
@@ -5531,6 +5705,7 @@ int sqlite3PagerWrite(DbPage *pDbPage){
   Pager *pPager = pPg->pPager;
   Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize);
 
+  assert( (pPg->flags & PGHDR_MMAP)==0 );
   assert( pPager->eState>=PAGER_WRITER_LOCKED );
   assert( pPager->eState!=PAGER_ERROR );
   assert( assert_pager_state(pPager) );
@@ -6087,7 +6262,7 @@ int sqlite3PagerRollback(Pager *pPager){
   }
 
   assert( pPager->eState==PAGER_READER || rc!=SQLITE_OK );
-  assert( rc==SQLITE_OK || rc==SQLITE_FULL
+  assert( rc==SQLITE_OK || rc==SQLITE_FULL || rc==SQLITE_CORRUPT
           || rc==SQLITE_NOMEM || (rc&0xFF)==SQLITE_IOERR );
 
   /* If an error occurs during a ROLLBACK, we can no longer trust the pager
@@ -6821,11 +6996,12 @@ static int pagerOpenWal(Pager *pPager){
   ** (e.g. due to malloc() failure), return an error code.
   */
   if( rc==SQLITE_OK ){
-    rc = sqlite3WalOpen(pPager->pVfs, 
+    rc = sqlite3WalOpen(pPager->pVfs,
         pPager->fd, pPager->zWal, pPager->exclusiveMode,
         pPager->journalSizeLimit, &pPager->pWal
     );
   }
+  pagerFixMaplimit(pPager);
 
   return rc;
 }
@@ -6916,6 +7092,7 @@ int sqlite3PagerCloseWal(Pager *pPager){
       rc = sqlite3WalClose(pPager->pWal, pPager->ckptSyncFlags,
                            pPager->pageSize, (u8*)pPager->pTmpSpace);
       pPager->pWal = 0;
+      pagerFixMaplimit(pPager);
     }
   }
   return rc;

src/pager.h

@@ -78,6 +78,12 @@ typedef struct PgHdr DbPage;
 #define PAGER_JOURNALMODE_MEMORY      4   /* In-memory journal file */
 #define PAGER_JOURNALMODE_WAL         5   /* Use write-ahead logging */
 
+/*
+** Flags that make up the mask passed to sqlite3PagerAcquire().
+*/
+#define PAGER_ACQUIRE_NOCONTENT     0x01  /* Do not load data from disk */
+#define PAGER_ACQUIRE_READONLY      0x02  /* Read-only page is acceptable */
+
 /*
 ** The remainder of this file contains the declarations of the functions
 ** that make up the Pager sub-system API. See source code comments for 
@@ -102,6 +108,7 @@ void sqlite3PagerSetBusyhandler(Pager*, int(*)(void *), void *);
 int sqlite3PagerSetPagesize(Pager*, u32*, int);
 int sqlite3PagerMaxPageCount(Pager*, int);
 void sqlite3PagerSetCachesize(Pager*, int);
+void sqlite3PagerSetMmapLimit(Pager *, sqlite3_int64);
 void sqlite3PagerShrink(Pager*);
 void sqlite3PagerSetSafetyLevel(Pager*,int,int,int);
 int sqlite3PagerLockingMode(Pager *, int);

src/pcache.h

@@ -53,6 +53,8 @@ struct PgHdr {
 #define PGHDR_REUSE_UNLIKELY    0x010  /* A hint that reuse is unlikely */
 #define PGHDR_DONT_WRITE        0x020  /* Do not write content to disk */
 
+#define PGHDR_MMAP              0x040  /* This is an mmap page object */
+
 /* Initialize and shutdown the page cache subsystem */
 int sqlite3PcacheInitialize(void);
 void sqlite3PcacheShutdown(void);

src/pragma.c

@@ -744,6 +744,40 @@ void sqlite3Pragma(
     }
   }else
 
+  /*
+  **  PRAGMA [database.]mmap_limit(N)
+  **
+  ** Used to set mapping size limit. The mapping size limit is
+  ** used to limit the aggregate size of all memory mapped regions of the
+  ** database file. If this parameter is set to zero, then memory mapping
+  ** is not used at all.  If N is negative, then the default memory map
+  ** limit determined by sqlite3_config(SQLITE_CONFIG_MMAP_LIMIT) is set.
+  ** The parameter N is measured in bytes.
+  **
+  ** This value is advisory.  The underlying VFS is free to memory map
+  ** as little or as much as it wants.  Except, if N is set to 0 then the
+  ** upper layers will never invoke the xFetch interfaces to the VFS.
+  */
+  if( sqlite3StrICmp(zLeft,"mmap_limit")==0 ){
+    sqlite3_int64 mx;
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( zRight ){
+      int ii;
+      sqlite3Atoi64(zRight, &mx, 1000, SQLITE_UTF8);
+      if( mx<0 ) mx = sqlite3GlobalConfig.mxMmap;
+      if( pId2->n==0 ) db->mxMmap = mx;
+      for(ii=db->nDb-1; ii>=0; ii--){
+        if( db->aDb[ii].pBt && (ii==iDb || pId2->n==0) ){
+          sqlite3BtreeSetMmapLimit(db->aDb[ii].pBt, mx);
+        }
+      }
+    }
+    mx = -1;
+    if( sqlite3_file_control(db,zDb,SQLITE_FCNTL_MMAP_LIMIT,&mx)==SQLITE_OK ){
+      returnSingleInt(pParse, "mmap_limit", mx);
+    }
+  }else
+
   /*
   **   PRAGMA temp_store
   **   PRAGMA temp_store = "default"|"memory"|"file"

src/shell.c

@@ -1552,6 +1552,43 @@ static int booleanValue(char *zArg){
   return 0;
 }
 
+/*
+** Interpret zArg as an integer value, possibly with suffixes.
+*/
+static sqlite3_int64 integerValue(const char *zArg){
+  sqlite3_int64 v = 0;
+  static const struct { char *zSuffix; int iMult; } aMult[] = {
+    { "KiB", 1024 },
+    { "MiB", 1024*1024 },
+    { "GiB", 1024*1024*1024 },
+    { "KB",  1000 },
+    { "MB",  1000000 },
+    { "GB",  1000000000 },
+    { "K",   1000 },
+    { "M",   1000000 },
+    { "G",   1000000000 },
+  };
+  int i;
+  int isNeg = 0;
+  if( zArg[0]=='-' ){
+    isNeg = 1;
+    zArg++;
+  }else if( zArg[0]=='+' ){
+    zArg++;
+  }
+  while( isdigit(zArg[0]) ){
+    v = v*10 + zArg[0] - '0';
+    zArg++;
+  }
+  for(i=0; i<sizeof(aMult)/sizeof(aMult[0]); i++){
+    if( sqlite3_stricmp(aMult[i].zSuffix, zArg)==0 ){
+      v *= aMult[i].iMult;
+      break;
+    }
+  }
+  return isNeg? -v : v;
+}
+
 /*
 ** Close an output file, assuming it is not stderr or stdout
 */
@@ -2469,7 +2506,7 @@ static int do_meta_command(char *zLine, struct callback_data *p){
         /* sqlite3_test_control(int, uint) */
         case SQLITE_TESTCTRL_PENDING_BYTE:        
           if( nArg==3 ){
-            unsigned int opt = (unsigned int)atoi(azArg[2]);        
+            unsigned int opt = (unsigned int)integerValue(azArg[2]);        
             rc = sqlite3_test_control(testctrl, opt);
             printf("%d (0x%08x)\n", rc, rc);
           } else {
@@ -2561,7 +2598,7 @@ static int do_meta_command(char *zLine, struct callback_data *p){
 #if defined(SQLITE_DEBUG) && defined(SQLITE_ENABLE_WHERETRACE)
   if( c=='w' && strncmp(azArg[0], "wheretrace", n)==0 ){
     extern int sqlite3WhereTrace;
-    sqlite3WhereTrace = atoi(azArg[1]);
+    sqlite3WhereTrace = booleanValue(azArg[1]);
   }else
 #endif
 
@@ -2882,6 +2919,7 @@ static const char zOptions[] =
   "   -interactive         force interactive I/O\n"
   "   -line                set output mode to 'line'\n"
   "   -list                set output mode to 'list'\n"
+  "   -mmap N              default mmap size set to N\n"
 #ifdef SQLITE_ENABLE_MULTIPLEX
   "   -multiplex           enable the multiplexor VFS\n"
 #endif
@@ -3001,12 +3039,7 @@ int main(int argc, char **argv){
       sqlite3_int64 szHeap;
 
       zSize = cmdline_option_value(argc, argv, ++i);
-      szHeap = atoi(zSize);
+      szHeap = integerValue(zSize);
-      for(j=0; (c = zSize[j])!=0; j++){
-        if( c=='M' ){ szHeap *= 1000000; break; }
-        if( c=='K' ){ szHeap *= 1000; break; }
-        if( c=='G' ){ szHeap *= 1000000000; break; }
-      }
       if( szHeap>0x7fff0000 ) szHeap = 0x7fff0000;
       sqlite3_config(SQLITE_CONFIG_HEAP, malloc((int)szHeap), (int)szHeap, 64);
 #endif
@@ -3026,6 +3059,8 @@ int main(int argc, char **argv){
       extern int sqlite3_multiple_initialize(const char*,int);
       sqlite3_multiplex_initialize(0, 1);
 #endif
+    }else if( strcmp(z,"-mmap")==0 ){
+      sqlite3_config(SQLITE_CONFIG_MMAP_LIMIT, integerValue(cmdline_option_value(argc,argv,++i)));
     }else if( strcmp(z,"-vfs")==0 ){
       sqlite3_vfs *pVfs = sqlite3_vfs_find(cmdline_option_value(argc,argv,++i));
       if( pVfs ){
@@ -3111,6 +3146,8 @@ int main(int argc, char **argv){
       stdin_is_interactive = 0;
     }else if( strcmp(z,"-heap")==0 ){
       i++;
+    }else if( strcmp(z,"-mmap")==0 ){
+      i++;
     }else if( strcmp(z,"-vfs")==0 ){
       i++;
 #ifdef SQLITE_ENABLE_VFSTRACE

src/sqlite.h.in

@@ -470,6 +470,7 @@ int sqlite3_exec(
 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
 #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
+#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
@@ -728,6 +729,9 @@ struct sqlite3_io_methods {
   void (*xShmBarrier)(sqlite3_file*);
   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
   /* Methods above are valid for version 2 */
+  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
+  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
+  /* Methods above are valid for version 3 */
   /* Additional methods may be added in future releases */
 };
 
@@ -882,6 +886,12 @@ struct sqlite3_io_methods {
 ** written into memory obtained from [sqlite3_malloc()].  The caller should
 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
 **
+** <li>[[SQLITE_FCNTL_MMAP_LIMIT]]
+** The argument is assumed to pointer to a value of type sqlite3_int64 that
+** is an advisory maximum number of bytes in the file to memory map.  The
+** pointer is overwritten with the old value.  The limit is not changed if
+** the original value pointed to is negative.
+**
 ** </ul>
 */
 #define SQLITE_FCNTL_LOCKSTATE               1
@@ -900,6 +910,7 @@ struct sqlite3_io_methods {
 #define SQLITE_FCNTL_PRAGMA                 14
 #define SQLITE_FCNTL_BUSYHANDLER            15
 #define SQLITE_FCNTL_TEMPFILENAME           16
+#define SQLITE_FCNTL_MMAP_LIMIT             18
 
 /*
 ** CAPI3REF: Mutex Handle
@@ -1628,6 +1639,19 @@ struct sqlite3_mem_methods {
 ** points to has just been executed. Or, if the fourth parameter is 2, then
 ** the connection being passed as the second parameter is being closed. The
 ** third parameter is passed NULL In this case.
+**
+** [[SQLITE_CONFIG_MMAP_LIMIT]]
+** <dt>SQLITE_CONFIG_MMAP_LIMIT
+** <dd>The sole argument should be a 64-bit integer (an sqlite3_int64) that
+** is the default maximum number of bytes of process address space that
+** should be used for accessing each database file using memory mapping.
+** The default setting can be overridden by each database connection using
+** either the [PRAGMA mmap_limit] command or the "mmaplimit" query parameter
+** on the [URI filename] when opening the databaes file or by using the
+** [SQLITE_FCNTL_MMAP_LIMIT] file control.  The value set here overrides the
+** compile-time default that is set using the [SQLITE_DEFAULT_MMAP_LIMIT]
+** compile-time option.  If the argument to this option is negative, then
+** the memory map limit is set to the compile-time default.
 ** </dl>
 */
 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
@@ -1651,6 +1675,7 @@ struct sqlite3_mem_methods {
 #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
 #define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
+#define SQLITE_CONFIG_MMAP_LIMIT   22  /* sqlite3_int64 */
 
 /*
 ** CAPI3REF: Database Connection Configuration Options

src/sqliteInt.h

@@ -834,6 +834,7 @@ struct sqlite3 {
   int nDb;                      /* Number of backends currently in use */
   int flags;                    /* Miscellaneous flags. See below */
   i64 lastRowid;                /* ROWID of most recent insert (see above) */
+  i64 mxMmap;                   /* Default mmap_limit setting */
   unsigned int openFlags;       /* Flags passed to sqlite3_vfs.xOpen() */
   int errCode;                  /* Most recent error code (SQLITE_*) */
   int errMask;                  /* & result codes with this before returning */
@@ -2505,6 +2506,7 @@ struct Sqlite3Config {
   void *pHeap;                      /* Heap storage space */
   int nHeap;                        /* Size of pHeap[] */
   int mnReq, mxReq;                 /* Min and max heap requests sizes */
+  sqlite3_int64 mxMmap;             /* Maximum mmap() space per open file */
   void *pScratch;                   /* Scratch memory */
   int szScratch;                    /* Size of each scratch buffer */
   int nScratch;                     /* Number of scratch buffers */

src/sqliteLimit.h

@@ -206,3 +206,23 @@
 #ifndef SQLITE_MAX_TRIGGER_DEPTH
 # define SQLITE_MAX_TRIGGER_DEPTH 1000
 #endif
+
+/*
+** Default maximum size of memory used by xFetch in the VFS.
+*/
+#ifdef __APPLE__
+# include <TargetConditionals.h>
+# if TARGET_OS_IPHONE
+#   define SQLITE_DEFAULT_MMAP_LIMIT 0
+# endif
+#endif
+#ifndef SQLITE_DEFAULT_MMAP_LIMIT
+# if defined(__linux__) \
+  || defined(_WIN32) \
+  || (defined(__APPLE__) && defined(__MACH__)) \
+  || defined(__sun)
+#   define SQLITE_DEFAULT_MMAP_LIMIT 268435456 /* = 256*1024*1024 */
+# else
+#   define SQLITE_DEFAULT_MMAP_LIMIT 0
+# endif
+#endif

src/test1.c

@@ -5844,6 +5844,31 @@ static int test_test_control(
   return TCL_OK;
 }
 
+#if SQLITE_OS_UNIX
+#include <sys/time.h>
+#include <sys/resource.h>
+
+static int test_getrusage(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  char buf[1024];
+  struct rusage r;
+  memset(&r, 0, sizeof(r));
+  getrusage(RUSAGE_SELF, &r);
+
+  sprintf(buf, "ru_utime=%d.%06d ru_stime=%d.%06d ru_minflt=%d ru_majflt=%d", 
+    (int)r.ru_utime.tv_sec, (int)r.ru_utime.tv_usec, 
+    (int)r.ru_stime.tv_sec, (int)r.ru_stime.tv_usec, 
+    (int)r.ru_minflt, (int)r.ru_majflt
+  );
+  Tcl_SetObjResult(interp, Tcl_NewStringObj(buf, -1));
+  return TCL_OK;
+}
+#endif
+
 #if SQLITE_OS_WIN
 /*
 ** Information passed from the main thread into the windows file locker
@@ -6233,6 +6258,9 @@ int Sqlitetest1_Init(Tcl_Interp *interp){
      { "print_explain_query_plan", test_print_eqp, 0  },
 #endif
      { "sqlite3_test_control", test_test_control },
+#if SQLITE_OS_UNIX
+     { "getrusage", test_getrusage },
+#endif
   };
   static int bitmask_size = sizeof(Bitmask)*8;
   int i;

src/test_syscall.c

@@ -23,7 +23,7 @@
 **
 **         open        close      access   getcwd   stat      fstat    
 **         ftruncate   fcntl      read     pread    pread64   write
-**         pwrite      pwrite64   fchmod   fallocate
+**         pwrite      pwrite64   fchmod   fallocate mmap
 **
 **   test_syscall uninstall
 **     Uninstall all wrapper functions.
@@ -81,6 +81,7 @@
 /* From test1.c */
 extern const char *sqlite3TestErrorName(int);
 
+#include <sys/mman.h>
 #include <sys/types.h>
 #include <errno.h>
 
@@ -106,7 +107,8 @@ static int ts_pwrite(int fd, const void *aBuf, size_t nBuf, off_t off);
 static int ts_pwrite64(int fd, const void *aBuf, size_t nBuf, off_t off);
 static int ts_fchmod(int fd, mode_t mode);
 static int ts_fallocate(int fd, off_t off, off_t len);
-
+static void *ts_mmap(void *, size_t, int, int, int, off_t);
+static void *ts_mremap(void*, size_t, size_t, int, ...);
 
 struct TestSyscallArray {
   const char *zName;
@@ -131,6 +133,8 @@ struct TestSyscallArray {
   /* 13 */ { "pwrite64",  (sqlite3_syscall_ptr)ts_pwrite64,  0, 0, 0 },
   /* 14 */ { "fchmod",    (sqlite3_syscall_ptr)ts_fchmod,    0, 0, 0 },
   /* 15 */ { "fallocate", (sqlite3_syscall_ptr)ts_fallocate, 0, 0, 0 },
+  /* 16 */ { "mmap",      (sqlite3_syscall_ptr)ts_mmap,      0, 0, 0 },
+  /* 17 */ { "mremap",    (sqlite3_syscall_ptr)ts_mremap,    0, 0, 0 },
            { 0, 0, 0, 0, 0 }
 };
 
@@ -152,6 +156,8 @@ struct TestSyscallArray {
                        aSyscall[13].xOrig)
 #define orig_fchmod    ((int(*)(int,mode_t))aSyscall[14].xOrig)
 #define orig_fallocate ((int(*)(int,off_t,off_t))aSyscall[15].xOrig)
+#define orig_mmap      ((void*(*)(void*,size_t,int,int,int,off_t))aSyscall[16].xOrig)
+#define orig_mremap    ((void*(*)(void*,size_t,size_t,int,...))aSyscall[17].xOrig)
 
 /*
 ** This function is called exactly once from within each invocation of a
@@ -377,6 +383,31 @@ static int ts_fallocate(int fd, off_t off, off_t len){
   return orig_fallocate(fd, off, len);
 }
 
+static void *ts_mmap(
+  void *pAddr, 
+  size_t nByte, 
+  int prot, 
+  int flags, 
+  int fd, 
+  off_t iOff
+){
+  if( tsIsFailErrno("mmap") ){
+    return MAP_FAILED;
+  }
+  return orig_mmap(pAddr, nByte, prot, flags, fd, iOff);
+}
+
+static void *ts_mremap(void *a, size_t b, size_t c, int d, ...){
+  va_list ap;
+  void *pArg;
+  if( tsIsFailErrno("mremap") ){
+    return MAP_FAILED;
+  }
+  va_start(ap, d);
+  pArg = va_arg(ap, void *);
+  return orig_mremap(a, b, c, d, pArg);
+}
+
 static int test_syscall_install(
   void * clientData,
   Tcl_Interp *interp,

src/wal.c

@@ -1208,7 +1208,7 @@ finished:
     */
     if( pWal->hdr.nPage ){
       sqlite3_log(SQLITE_OK, "Recovered %d frames from WAL file %s",
-          pWal->hdr.nPage, pWal->zWalName
+          pWal->hdr.mxFrame, pWal->zWalName
       );
     }
   }
@@ -1722,8 +1722,8 @@ static int walCheckpoint(
       rc = sqlite3OsSync(pWal->pWalFd, sync_flags);
     }
 
-    /* If the database file may grow as a result of this checkpoint, hint
+    /* If the database may grow as a result of this checkpoint, hint
-    ** about the eventual size of the db file to the VFS layer. 
+    ** about the eventual size of the db file to the VFS layer.
     */
     if( rc==SQLITE_OK ){
       i64 nReq = ((i64)mxPage * szPage);
@@ -1733,6 +1733,7 @@ static int walCheckpoint(
       }
     }
 
+
     /* Iterate through the contents of the WAL, copying data to the db file. */
     while( rc==SQLITE_OK && 0==walIteratorNext(pIter, &iDbpage, &iFrame) ){
       i64 iOffset;
@@ -2287,19 +2288,17 @@ void sqlite3WalEndReadTransaction(Wal *pWal){
 }
 
 /*
-** Read a page from the WAL, if it is present in the WAL and if the 
+** Search the wal file for page pgno. If found, set *piRead to the frame that
-** current read transaction is configured to use the WAL.  
+** contains the page. Otherwise, if pgno is not in the wal file, set *piRead
+** to zero.
 **
-** The *pInWal is set to 1 if the requested page is in the WAL and
+** Return SQLITE_OK if successful, or an error code if an error occurs. If an
-** has been loaded.  Or *pInWal is set to 0 if the page was not in 
+** error does occur, the final value of *piRead is undefined.
-** the WAL and needs to be read out of the database.
 */
-int sqlite3WalRead(
+int sqlite3WalFindFrame(
   Wal *pWal,                      /* WAL handle */
   Pgno pgno,                      /* Database page number to read data for */
-  int *pInWal,                    /* OUT: True if data is read from WAL */
+  u32 *piRead                     /* OUT: Frame number (or zero) */
-  int nOut,                       /* Size of buffer pOut in bytes */
-  u8 *pOut                        /* Buffer to write page data to */
 ){
   u32 iRead = 0;                  /* If !=0, WAL frame to return data from */
   u32 iLast = pWal->hdr.mxFrame;  /* Last page in WAL for this reader */
@@ -2315,7 +2314,7 @@ int sqlite3WalRead(
   ** WAL were empty.
   */
   if( iLast==0 || pWal->readLock==0 ){
-    *pInWal = 0;
+    *piRead = 0;
     return SQLITE_OK;
   }
 
@@ -2386,26 +2385,31 @@ int sqlite3WalRead(
   }
 #endif
 
-  /* If iRead is non-zero, then it is the log frame number that contains the
+  *piRead = iRead;
-  ** required page. Read and return data from the log file.
-  */
-  if( iRead ){
-    int sz;
-    i64 iOffset;
-    sz = pWal->hdr.szPage;
-    sz = (sz&0xfe00) + ((sz&0x0001)<<16);
-    testcase( sz<=32768 );
-    testcase( sz>=65536 );
-    iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
-    *pInWal = 1;
-    /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
-    return sqlite3OsRead(pWal->pWalFd, pOut, (nOut>sz ? sz : nOut), iOffset);
-  }
-
-  *pInWal = 0;
   return SQLITE_OK;
 }
 
+/*
+** Read the contents of frame iRead from the wal file into buffer pOut
+** (which is nOut bytes in size). Return SQLITE_OK if successful, or an
+** error code otherwise.
+*/
+int sqlite3WalReadFrame(
+  Wal *pWal,                      /* WAL handle */
+  u32 iRead,                      /* Frame to read */
+  int nOut,                       /* Size of buffer pOut in bytes */
+  u8 *pOut                        /* Buffer to write page data to */
+){
+  int sz;
+  i64 iOffset;
+  sz = pWal->hdr.szPage;
+  sz = (sz&0xfe00) + ((sz&0x0001)<<16);
+  testcase( sz<=32768 );
+  testcase( sz>=65536 );
+  iOffset = walFrameOffset(iRead, sz) + WAL_FRAME_HDRSIZE;
+  /* testcase( IS_BIG_INT(iOffset) ); // requires a 4GiB WAL */
+  return sqlite3OsRead(pWal->pWalFd, pOut, (nOut>sz ? sz : nOut), iOffset);
+}
 
 /* 
 ** Return the size of the database in pages (or zero, if unknown).
@@ -2952,6 +2956,9 @@ int sqlite3WalCheckpoint(
   /* Read the wal-index header. */
   if( rc==SQLITE_OK ){
     rc = walIndexReadHdr(pWal, &isChanged);
+    if( isChanged && pWal->pDbFd->pMethods->iVersion>=3 ){
+      sqlite3OsUnfetch(pWal->pDbFd, 0, 0);
+    }
   }
 
   /* Copy data from the log to the database file. */

src/wal.h

@@ -31,7 +31,6 @@
 # define sqlite3WalClose(w,x,y,z)                0
 # define sqlite3WalBeginReadTransaction(y,z)     0
 # define sqlite3WalEndReadTransaction(z)
-# define sqlite3WalRead(v,w,x,y,z)               0
 # define sqlite3WalDbsize(y)                     0
 # define sqlite3WalBeginWriteTransaction(y)      0
 # define sqlite3WalEndWriteTransaction(x)        0
@@ -71,7 +70,8 @@ int sqlite3WalBeginReadTransaction(Wal *pWal, int *);
 void sqlite3WalEndReadTransaction(Wal *pWal);
 
 /* Read a page from the write-ahead log, if it is present. */
-int sqlite3WalRead(Wal *pWal, Pgno pgno, int *pInWal, int nOut, u8 *pOut);
+int sqlite3WalFindFrame(Wal *, Pgno, u32 *);
+int sqlite3WalReadFrame(Wal *, u32, int, u8 *);
 
 /* If the WAL is not empty, return the size of the database. */
 Pgno sqlite3WalDbsize(Wal *pWal);

test/btreefault.test

@@ -0,0 +1,50 @@
+# 2013 April 02
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+# This file contains fault injection tests designed to test the btree.c 
+# module.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/malloc_common.tcl
+set testprefix btreefault
+
+do_test 1-pre1 {
+  execsql {
+    PRAGMA auto_vacuum = incremental;
+    PRAGMA journal_mode = DELETE;
+    CREATE TABLE t1(a PRIMARY KEY, b);
+    INSERT INTO t1 VALUES(randomblob(1000), randomblob(100));
+    INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+    INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+    INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+    INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+    DELETE FROM t1 WHERE rowid%2;
+  }
+  faultsim_save_and_close
+} {}
+
+do_faultsim_test 1 -prep {
+  faultsim_restore_and_reopen
+  set ::STMT [sqlite3_prepare db "SELECT * FROM t1 ORDER BY a" -1 DUMMY]
+  sqlite3_step $::STMT
+  sqlite3_step $::STMT
+} -body {
+  execsql { PRAGMA incremental_vacuum = 10 }
+} -test {
+  sqlite3_finalize $::STMT
+  faultsim_test_result {0 {}} 
+  faultsim_integrity_check
+}
+
+finish_test
+

test/dbstatus2.test

@@ -40,6 +40,7 @@ proc db_write {db {reset 0}} {
 do_test 1.1 {
   db close
   sqlite3 db test.db
+  execsql { PRAGMA mmap_limit = 0 }
   expr {[file size test.db] / 1024}
 } 6
 

test/exclusive2.test

@@ -25,6 +25,14 @@ ifcapable {!pager_pragmas} {
   return
 }
 
+# Tests in this file verify that locking_mode=exclusive causes SQLite to
+# use cached pages even if the database is changed on disk. This doesn't
+# work with mmap.
+if {[permutation]!="nommap"} {
+  finish_test
+  return
+}
+
 # This module does not work right if the cache spills at unexpected
 # moments.  So disable the soft-heap-limit.
 #

test/func.test

@@ -1273,11 +1273,13 @@ do_test func-29.3 {
   sqlite3_db_status db CACHE_MISS 1
   db eval {SELECT typeof(+x) FROM t29 ORDER BY id}
 } {integer null real blob text}
-do_test func-29.4 {
+if {[permutation] == "nommap"} {
-  set x [lindex [sqlite3_db_status db CACHE_MISS 1] 1]
+  do_test func-29.4 {
-  if {$x>100} {set x many}
+    set x [lindex [sqlite3_db_status db CACHE_MISS 1] 1]
-  set x
+    if {$x>100} {set x many}
-} {many}
+    set x
+  } {many}
+}
 do_test func-29.5 {
   db close
   sqlite3 db test.db

test/incrblob.test

@@ -123,6 +123,7 @@ foreach AutoVacuumMode [list 0 1] {
   forcedelete test.db test.db-journal
 
   sqlite3 db test.db
+  execsql "PRAGMA mmap_limit = 0"
   execsql "PRAGMA auto_vacuum = $AutoVacuumMode"
 
   do_test incrblob-2.$AutoVacuumMode.1 {
@@ -149,6 +150,7 @@ foreach AutoVacuumMode [list 0 1] {
     # Open and close the db to make sure the page cache is empty.
     db close
     sqlite3 db test.db
+    execsql "PRAGMA mmap_limit = 0"
   
     # Read the last 20 bytes of the blob via a blob handle.
     set ::blob [db incrblob blobs v 1]
@@ -171,6 +173,7 @@ foreach AutoVacuumMode [list 0 1] {
     # Open and close the db to make sure the page cache is empty.
     db close
     sqlite3 db test.db
+    execsql "PRAGMA mmap_limit = 0"
   
     # Write the second-to-last 20 bytes of the blob via a blob handle.
     #
@@ -200,6 +203,7 @@ foreach AutoVacuumMode [list 0 1] {
     # Open and close the db to make sure the page cache is empty.
     db close
     sqlite3 db test.db
+    execsql { PRAGMA mmap_limit = 0 }
 
     execsql { SELECT i FROM blobs } 
   } {45}

test/malloc_common.tcl

@@ -264,7 +264,7 @@ proc faultsim_test_result_int {args} {
   set t [list $testrc $testresult]
   set r $args
   if { ($testnfail==0 && $t != [lindex $r 0]) || [lsearch $r $t]<0 } {
-    error "nfail=$testnfail rc=$testrc result=$testresult"
+    error "nfail=$testnfail rc=$testrc result=$testresult list=$r"
   }
 }
 

test/mmap1.test

@@ -0,0 +1,250 @@
+# 2013 March 20
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+source $testdir/lock_common.tcl
+set testprefix mmap1
+
+proc nRead {db} {
+  set bt [btree_from_db $db]
+  db_enter $db
+  array set stats [btree_pager_stats $bt]
+  db_leave $db
+  # puts [array get stats]
+  return $stats(read)
+}
+
+foreach {t mmap_limit nRead c2init} {
+  1.1 { PRAGMA mmap_limit = 67108864 }   4 {}
+  1.2 { PRAGMA mmap_limit =    53248 } 150 {}
+  1.3 { PRAGMA mmap_limit =        0 } 344 {}
+  1.4 { PRAGMA mmap_limit = 67108864 }   4 {PRAGMA mmap_limit = 67108864 }
+  1.5 { PRAGMA mmap_limit =    53248 } 150 {PRAGMA mmap_limit = 67108864 }
+  1.6 { PRAGMA mmap_limit =        0 } 344 {PRAGMA mmap_limit = 67108864 }
+} {
+  do_multiclient_test tn {
+    sql1 {PRAGMA page_size=1024}
+    sql1 $mmap_limit
+    sql2 $c2init
+
+    code2 {
+      set ::rcnt 0
+      proc rblob {n} {
+        set ::rcnt [expr (($::rcnt << 3) + $::rcnt + 456) & 0xFFFFFFFF]
+        set str [format %.8x [expr $::rcnt ^ 0xbdf20da3]] 
+        string range [string repeat $str [expr $n/4]] 1 $n
+      }
+      db2 func rblob rblob
+    }
+
+    sql2 {
+      PRAGMA page_size=1024;
+      PRAGMA auto_vacuum = 1;
+      CREATE TABLE t1(a, b, UNIQUE(a, b));
+      INSERT INTO t1 VALUES(rblob(500), rblob(500));
+      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    2
+      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    4
+      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    8
+      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   16
+      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   32
+    }
+    do_test $t.$tn.1 {
+      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
+    } {32 ok 77}
+
+    # Have connection 2 shrink the file. Check connection 1 can still read it.
+    sql2 { DELETE FROM t1 WHERE rowid%2; }
+    do_test $t.$tn.2 {
+      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
+    } {16 ok 42}
+
+    # Have connection 2 grow the file. Check connection 1 can still read it.
+    sql2 { INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1 }
+    do_test $t.$tn.3 {
+      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
+    } {32 ok 79}
+
+    # Have connection 2 grow the file again. Check connection 1 is still ok.
+    sql2 { INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1 }
+    do_test $t.$tn.4 {
+      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
+    } {64 ok 149}
+
+    # Check that the number of pages read by connection 1 indicates that the
+    # "PRAGMA mmap_limit" command worked.
+    do_test $t.$tn.5 { nRead db } $nRead
+  }
+}
+
+set ::rcnt 0
+proc rblob {n} {
+  set ::rcnt [expr (($::rcnt << 3) + $::rcnt + 456) & 0xFFFFFFFF]
+  set str [format %.8x [expr $::rcnt ^ 0xbdf20da3]] 
+  string range [string repeat $str [expr $n/4]] 1 $n
+}
+
+reset_db
+db func rblob rblob
+
+do_execsql_test 2.1 {
+  PRAGMA auto_vacuum = 1;
+  PRAGMA mmap_limit = 67108864;
+  PRAGMA journal_mode = wal;
+  CREATE TABLE t1(a, b, UNIQUE(a, b));
+  INSERT INTO t1 VALUES(rblob(500), rblob(500));
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    2
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    4
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    8
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   16
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   32
+  PRAGMA wal_checkpoint;
+} {67108864 wal 0 103 103}
+
+do_execsql_test 2.2 {
+  PRAGMA auto_vacuum;
+  SELECT count(*) FROM t1;
+} {1 32}
+
+do_test 2.3 {
+  sqlite3 db2 test.db
+  db2 func rblob rblob
+  db2 eval { 
+    DELETE FROM t1 WHERE (rowid%4);
+    PRAGMA wal_checkpoint;
+  }
+  db2 eval { 
+    INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    16
+    SELECT count(*) FROM t1;
+  }
+} {16}
+
+do_execsql_test 2.4 {
+  PRAGMA wal_checkpoint;
+} {0 24 24}
+
+db2 close
+reset_db
+db func rblob rblob
+do_execsql_test 3.1 {
+  PRAGMA auto_vacuum = 1;
+
+  CREATE TABLE t1(a, b, UNIQUE(a, b));
+  INSERT INTO t1 VALUES(rblob(500), rblob(500));
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    2
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    4
+  INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    8
+
+  CREATE TABLE t2(a, b, UNIQUE(a, b));
+  INSERT INTO t2 SELECT * FROM t1;
+} {}
+
+do_test 3.2 {
+  set nRow 0
+  db eval {SELECT * FROM t2 ORDER BY a, b} {
+    if {$nRow==4} { db eval { DELETE FROM t1 } }
+    incr nRow
+  }
+  set nRow
+} {8}
+
+#-------------------------------------------------------------------------
+# Ensure that existing cursors using xFetch() pages see changes made
+# to rows using the incrblob API.
+#
+reset_db
+set aaa [string repeat a 400]
+set bbb [string repeat b 400]
+set ccc [string repeat c 400]
+set ddd [string repeat d 400]
+set eee [string repeat e 400]
+
+do_execsql_test 4.1 {
+  PRAGMA page_size = 1024;
+  CREATE TABLE t1(x);
+  INSERT INTO t1 VALUES($aaa);
+  INSERT INTO t1 VALUES($bbb);
+  INSERT INTO t1 VALUES($ccc);
+  INSERT INTO t1 VALUES($ddd);
+  SELECT * FROM t1;
+  BEGIN;
+} [list $aaa $bbb $ccc $ddd]
+
+do_test 4.2 {
+  set ::STMT [sqlite3_prepare db "SELECT * FROM t1 ORDER BY rowid" -1 dummy]
+  sqlite3_step $::STMT
+  sqlite3_column_text $::STMT 0
+} $aaa
+
+do_test 4.3 {
+  foreach r {2 3 4} {
+    set fd [db incrblob t1 x $r]
+    puts -nonewline $fd $eee
+    close $fd
+  }
+
+  set res [list]
+  while {"SQLITE_ROW" == [sqlite3_step $::STMT]} {
+    lappend res [sqlite3_column_text $::STMT 0]
+  }
+  set res
+} [list $eee $eee $eee]
+
+do_test 4.4 {
+  sqlite3_finalize $::STMT
+} SQLITE_OK
+
+do_execsql_test 4.5 { COMMIT }
+
+#-------------------------------------------------------------------------
+# Ensure that existing cursors holding xFetch() references are not 
+# confused if those pages are moved to make way for the root page of a
+# new table or index.
+#
+reset_db
+do_execsql_test 5.1 {
+  PRAGMA auto_vacuum = 2;
+  PRAGMA page_size = 1024;
+  CREATE TABLE t1(x);
+  INSERT INTO t1 VALUES($aaa);
+  INSERT INTO t1 VALUES($bbb);
+  INSERT INTO t1 VALUES($ccc);
+  INSERT INTO t1 VALUES($ddd);
+
+  PRAGMA auto_vacuum;
+  SELECT * FROM t1;
+} [list 2 $aaa $bbb $ccc $ddd]
+
+do_test 5.2 {
+  set ::STMT [sqlite3_prepare db "SELECT * FROM t1 ORDER BY rowid" -1 dummy]
+  sqlite3_step $::STMT
+  sqlite3_column_text $::STMT 0
+} $aaa
+
+do_execsql_test 5.3 {
+  CREATE TABLE t2(x);
+  INSERT INTO t2 VALUES('tricked you!');
+  INSERT INTO t2 VALUES('tricked you!');
+}
+
+do_test 5.4 {
+  sqlite3_step $::STMT
+  sqlite3_column_text $::STMT 0
+} $bbb
+
+do_test 5.5 {
+  sqlite3_finalize $::STMT
+} SQLITE_OK
+
+finish_test
+
+

test/mmap2.test

@@ -0,0 +1,82 @@
+# 2013 March 20
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+# This file tests the effect of the mmap() or mremap() system calls 
+# returning an error on the library. 
+#
+# If either mmap() or mremap() fails, SQLite should log an error 
+# message, then continue accessing the database using read() and 
+# write() exclusively.
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix mmap2
+
+if {$::tcl_platform(platform)!="unix" || [test_syscall defaultvfs] != "unix"} {
+  finish_test
+  return
+}
+
+db close
+sqlite3_shutdown
+test_sqlite3_log xLog
+proc xLog {error_code msg} {
+  if {[string match os_unix.c* $msg]} {
+    lappend ::log $msg 
+  }
+}
+
+foreach syscall {mmap mremap} {
+  test_syscall uninstall 
+  if {[catch {test_syscall install $syscall}]} continue
+
+  for {set i 1} {$i < 20} {incr i} {
+    reset_db
+
+    test_syscall fault $i 1
+    test_syscall errno $syscall ENOMEM
+    set ::log ""
+
+    do_execsql_test 1.$syscall.$i.1 {
+      CREATE TABLE t1(a, b, UNIQUE(a, b));
+      INSERT INTO t1 VALUES(randomblob(1000), randomblob(1000));
+      INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+      INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+      INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+      INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+      INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+      INSERT INTO t1 SELECT randomblob(1000), randomblob(1000) FROM t1;
+    }
+
+    set nFail [test_syscall fault 0 0]
+
+    do_execsql_test 1.$syscall.$i.2 {
+      SELECT count(*) FROM t1;
+      PRAGMA integrity_check;
+    } {64 ok}
+
+    do_test 1.$syscall.$i.3 {
+      expr {$nFail==0 || $nFail==1}
+    } {1}
+
+    do_test 1.$syscall.$i.4.nFail=$nFail {
+      regexp ".*${syscall}.*" $::log
+    } [expr $nFail>0]
+  }
+}
+
+db close
+test_syscall uninstall 
+sqlite3_shutdown
+test_sqlite3_log 
+sqlite3_initialize
+finish_test

test/pagerfault.test

@@ -1246,5 +1246,62 @@ do_faultsim_test pagerfault-27 -faults ioerr-persistent -prep {
   faultsim_integrity_check
 }
 
+#-------------------------------------------------------------------------
+#
+do_test pagerfault-28-pre {
+  faultsim_delete_and_reopen
+  db func a_string a_string
+  execsql {
+    PRAGMA page_size = 512;
+
+    PRAGMA journal_mode = wal;
+    PRAGMA wal_autocheckpoint = 0;
+    PRAGMA cache_size = 100000;
+
+    BEGIN;
+      CREATE TABLE t2(a UNIQUE, b UNIQUE);
+      INSERT INTO t2 VALUES( a_string(800), a_string(800) );
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+      INSERT INTO t2 SELECT a_string(800), a_string(800) FROM t2;
+    COMMIT;
+    CREATE TABLE t1(a PRIMARY KEY, b);
+  }
+  expr {[file size test.db-shm] >= 96*1024}
+} {1}
+faultsim_save_and_close
+
+do_faultsim_test pagerfault-28 -faults oom* -prep {
+  faultsim_restore_and_reopen
+  execsql { PRAGMA mmap_limit=0 }
+
+  sqlite3 db2 test.db
+  db2 eval { SELECT count(*) FROM t2 }
+
+  db func a_string a_string
+  execsql { 
+    BEGIN;
+      INSERT INTO t1 VALUES(a_string(2000), a_string(2000));
+      INSERT INTO t1 VALUES(a_string(2000), a_string(2000));
+  }
+  set ::STMT [sqlite3_prepare db "SELECT * FROM t1 ORDER BY a" -1 DUMMY]
+  sqlite3_step $::STMT
+} -body {
+  execsql { ROLLBACK }
+} -test {
+  db2 close
+  sqlite3_finalize $::STMT
+  catchsql { ROLLBACK }
+  faultsim_integrity_check
+}
+
 finish_test
 

test/pageropt.test

@@ -92,7 +92,7 @@ do_test pageropt-1.5 {
   pagercount_sql {
     SELECT hex(x) FROM t1
   }
-} [list 6 0 0 $blobcontent]
+} [list [expr {[permutation]=="nommap" ? 6 : 1}] 0 0 $blobcontent]
 do_test pageropt-1.6 {
   pagercount_sql {
     SELECT hex(x) FROM t1

test/permutations.test

@@ -138,6 +138,14 @@ test_suite "veryquick" -prefix "" -description {
   test_set $allquicktests -exclude *malloc* *ioerr* *fault*
 ]
 
+test_suite "nommap" -prefix "nomm-" -description {
+  Similar to veryquick. Except with memory mapping disabled.
+} -presql {
+  pragma mmap_limit = 0;
+} -files [
+  test_set $allquicktests -exclude *malloc* *ioerr* *fault* -include malloc.test
+]
+
 test_suite "valgrind" -prefix "" -description {
   Run the "veryquick" test suite with a couple of multi-process tests (that
   fail under valgrind) omitted.

test/speed1p.test

@@ -24,6 +24,8 @@ set testdir [file dirname $argv0]
 source $testdir/tester.tcl
 speed_trial_init speed1
 
+sqlite3_memdebug_vfs_oom_test 0
+
 # Set a uniform random seed
 expr srand(0)
 
@@ -78,7 +80,6 @@ do_test speed1p-1.0 {
   }
 } {i2a i2b t1 t2}
 
-
 # 50000 INSERTs on an unindexed table
 #
 set list {}

test/syscall.test

@@ -60,7 +60,7 @@ foreach s {
     open close access getcwd stat fstat ftruncate
     fcntl read pread write pwrite fchmod fallocate
     pread64 pwrite64 unlink openDirectory mkdir rmdir 
-    statvfs fchown umask
+    statvfs fchown umask mmap munmap mremap
 } {
   if {[test_syscall exists $s]} {lappend syscall_list $s}
 }

test/sysfault.test

@@ -243,5 +243,35 @@ do_faultsim_test 3 -faults vfsfault-* -prep {
   faultsim_test_result {0 20000}
 }
 
-finish_test
+#-------------------------------------------------------------------------
+# Test errors in mmap().
+#
+proc vfsfault_install {} { 
+  test_syscall reset
+  test_syscall install {mmap}
+}
 
+faultsim_delete_and_reopen
+execsql {
+  CREATE TABLE t1(a, b);
+  INSERT INTO t1 VALUES(1, 2);
+}
+faultsim_save_and_close
+
+do_faultsim_test 4 -faults vfsfault-* -prep {
+  faultsim_restore_and_reopen
+  file_control_chunksize_test db main 8192
+  execsql { 
+    PRAGMA mmap_limit = 1000000;
+  }
+} -body {
+  test_syscall errno mmap     EACCES
+
+  execsql {
+    SELECT * FROM t1;
+  }
+} -test {
+  faultsim_test_result {0 {1 2}} {1 {disk I/O error}}
+}
+
+finish_test

test/wal.test

@@ -727,6 +727,8 @@ do_test wal-11.9 {
   list [expr [file size test.db]/1024] [log_deleted test.db-wal]
 } {37 1}
 sqlite3_wal db test.db
+set nWal 39
+if {[permutation]=="nommap"} {set nWal 37}
 do_test wal-11.10 {
   execsql {
     PRAGMA cache_size = 10;
@@ -735,7 +737,7 @@ do_test wal-11.10 {
       SELECT count(*) FROM t1;
   }
   list [expr [file size test.db]/1024] [file size test.db-wal]
-} [list 37 [wal_file_size 37 1024]]
+} [list 37 [wal_file_size $nWal 1024]]
 do_test wal-11.11 {
   execsql {
       SELECT count(*) FROM t1;
@@ -745,7 +747,7 @@ do_test wal-11.11 {
 } {32 16}
 do_test wal-11.12 {
   list [expr [file size test.db]/1024] [file size test.db-wal]
-} [list 37 [wal_file_size 37 1024]]
+} [list 37 [wal_file_size $nWal 1024]]
 do_test wal-11.13 {
   execsql {
     INSERT INTO t1 VALUES( blob(900) );
@@ -755,7 +757,7 @@ do_test wal-11.13 {
 } {17 ok}
 do_test wal-11.14 {
   list [expr [file size test.db]/1024] [file size test.db-wal]
-} [list 37 [wal_file_size 37 1024]]
+} [list 37 [wal_file_size $nWal 1024]]
 
 
 #-------------------------------------------------------------------------
@@ -1567,6 +1569,26 @@ ifcapable autovacuum {
   } [wal_file_size 1 1024]
 }
 
+reset_db
+do_test 25 {
+  sqlite3 db test.db
+
+  execsql {
+    CREATE TABLE t1(x, y);
+    PRAGMA journal_mode = WAL;
+    INSERT INTO t1 VALUES(1, 2);
+  }
+
+  execsql {
+    BEGIN;
+      CREATE TABLE t2(a, b);
+  }
+
+  hexio_write test.db-shm [expr 16*1024] [string repeat 0055 8192]
+  catchsql ROLLBACK
+} {0 {}}
+
+
 db close
 sqlite3_shutdown
 test_sqlite3_log

test/wal5.test

@@ -235,7 +235,15 @@ foreach {testprefix do_wal_checkpoint} {
     do_test 2.3.$tn.5 { sql1 { INSERT INTO t2 VALUES(3, 4) } } {}
     do_test 2.3.$tn.6 { file_page_counts } {1 4 1 4}
     do_test 2.3.$tn.7 { code1 { do_wal_checkpoint db -mode full } } {1 4 3}
-    do_test 2.3.$tn.8 { file_page_counts } {1 4 2 4}
+
+    # The checkpoint above only writes page 1 of the db file. The other
+    # page (page 2) is locked by the read-transaction opened by the
+    # [sql2] commmand above. So normally, the db is 1 page in size here.
+    # However, in mmap() mode, the db is pre-allocated to 2 pages at the
+    # start of the checkpoint, even though page 2 cannot be written.
+    set nDb 2
+    if {[permutation]=="no-mmap"} {set nDb 1}
+    do_test 2.3.$tn.8 { file_page_counts } [list $nDb 4 2 4]
   }
 
   # Check that checkpoints block on the correct locks. And respond correctly
@@ -343,4 +351,3 @@ foreach {testprefix do_wal_checkpoint} {
 
 
 finish_test
-