Avoid using the "direct overflow read" optimization to read large blobs if the

pager layer has a wal file open - even if the database header indicates that
the db is not a wal database.

FossilOrigin-Name: b54c15f11796a75683eec4b502a22ccb87d621c6

ext/rbu/rbudor.test

@@ -0,0 +1,59 @@
+# 2016 October 21
+#
+# 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 test file focuses on interactions between RBU and the feature
+# enabled by SQLITE_DIRECT_OVERFLOW_READ - Direct Overflow Read.
+#
+
+if {![info exists testdir]} {
+  set testdir [file join [file dirname [info script]] .. .. test]
+}
+source $testdir/tester.tcl
+set ::testprefix rbudor
+
+set bigA [string repeat a 5000]
+set bigB [string repeat b 5000]
+do_execsql_test 1.0 {
+  PRAGMA page_size = 1024;
+  CREATE TABLE t1(a INTEGER PRIMARY KEY, b BLOB);
+  INSERT INTO t1 VALUES(1, $bigA);
+} {}
+
+do_test 1.1 {
+  forcedelete rbu.db
+  sqlite3 rbu rbu.db 
+  rbu eval {
+    CREATE TABLE data_t1(a, b, rbu_control);
+    INSERT INTO data_t1 VALUES(2, $bigB, 0);
+  }
+  rbu close
+} {}
+
+do_test 1.2 {
+  sqlite3rbu rbu test.db rbu.db
+  while {[rbu state]!="checkpoint"} {
+    rbu step
+  }
+  rbu step
+  db eval { SELECT * FROM t1 }
+} [list 1 $bigA 2 $bigB]
+
+do_test 1.3 {
+  while {[rbu step]=="SQLITE_OK"} {}
+  rbu close
+} {SQLITE_DONE}
+
+do_execsql_test 1.4 {
+  SELECT * FROM t1 
+} [list 1 $bigA 2 $bigB]
+
+finish_test
+

manifest

@@ -1,5 +1,5 @@
-C If\sSQLITE_DIRECT_OVERFLOW_READ\sis\sdefined\sat\scompile\stime,\sadd\s"DIRECT_OVERFLOW_READ"\sto\sthe\slist\sof\ssymbols\sreturned\sby\s"PRAGMA\scompile_options".
+C Avoid\susing\sthe\s"direct\soverflow\sread"\soptimization\sto\sread\slarge\sblobs\sif\sthe\npager\slayer\shas\sa\swal\sfile\sopen\s-\seven\sif\sthe\sdatabase\sheader\sindicates\sthat\nthe\sdb\sis\snot\sa\swal\sdatabase.
-D 2016-10-21T10:09:22.112
+D 2016-10-21T10:49:39.630
 F Makefile.in 6fd48ffcf7c2deea7499062d1f3747f986c19678
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 5151cc64c4c05f3455f4f692ad11410a810d937f
@@ -247,6 +247,7 @@ F ext/rbu/rbuC.test efe47db508a0269b683cb2a1913a425ffd39a831
 F ext/rbu/rbu_common.tcl a38e8e2d4a50fd6aaf151633714c1b1d2fae3ead
 F ext/rbu/rbucrash.test 8d2ed5d4b05fef6c00c2a6b5f7ead71fa172a695
 F ext/rbu/rbudiff.test 3e605cf624d00d04d0fb1316a3acec4fbe3b3ac5
+F ext/rbu/rbudor.test 99b05cc0df613e962c2c8085cfb05686a09cf315
 F ext/rbu/rbufault.test cc0be8d5d392d98b0c2d6a51be377ea989250a89
 F ext/rbu/rbufault2.test 9a7f19edd6ea35c4c9f807d8a3db0a03a5670c06
 F ext/rbu/rbufault3.test 54a399888ac4af44c68f9f58afbed23149428bca
@@ -329,7 +330,7 @@ F src/auth.c 930b376a9c56998557367e6f7f8aaeac82a2a792
 F src/backup.c faf17e60b43233c214aae6a8179d24503a61e83b
 F src/bitvec.c 3ee4c8b2c94ed3a7377256e18199e6ff5cf33f63
 F src/btmutex.c bc87dd3b062cc26edfe79918de2200ccb8d41e73
-F src/btree.c 4d035fb52b0ef9658d43dfe604413185dff7a5d1
+F src/btree.c 0fde2593dcf004ac2e5d5af93867a9099ed3cc9d
 F src/btree.h d05b2fcc290991a8a3d9ea1816ddd55a4359dcde
 F src/btreeInt.h c18b7d2a3494695133e4e60ee36061d37f45d9a5
 F src/build.c 59dcfdc1ee55439d069af301ef7f2e84421b5102
@@ -373,8 +374,8 @@ F src/os_setup.h 0dbaea40a7d36bf311613d31342e0b99e2536586
 F src/os_unix.c be9ca0f901a2b6c1bc93dc338f4863675180c189
 F src/os_win.c cf90abd4e50d9f56d2c20ce8e005aff55d7bd8e9
 F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
-F src/pager.c 49b6c163832498838c92d0c4c90721576ae707b7
+F src/pager.c 549ed86833b484fa3cd4799e3289c83b3ace8859
-F src/pager.h 0a19b1e212d0f5d0507f186ae1cca4e523d09d1a
+F src/pager.h 07d6938df0b74e4abe8f57807a8b0e1084321d8b
 F src/parse.y 0338f906b61e311c2b7e11a3f89b0092c780b664
 F src/pcache.c 5ff2a08f76a9c1b22f43eb063b7068fb085465ac
 F src/pcache.h 2cedcd8407eb23017d92790b112186886e179490
@@ -1526,7 +1527,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P fd9c6ff05f2052810549a1a6a384f4b40f4ba4ac
+P b7d9727bff2e840af4b090872c991693e78e6076
-R 4fbfeb317fb8029064d3b09d0cf024a2
+R 775b940b506452362a073212102869ea
 U dan
-Z 8fb3e008f86324b83c8c0293ad05a979
+Z 738379ab10ae31c6f3af66e5c08bf61c

manifest.uuid

@@ -1 +1 @@
-b7d9727bff2e840af4b090872c991693e78e6076
+b54c15f11796a75683eec4b502a22ccb87d621c6

src/btree.c

@@ -4608,7 +4608,7 @@ static int accessPayload(
          && (bEnd || a==ovflSize)                              /* (6) */
          && pBt->inTransaction==TRANS_READ                     /* (4) */
          && (fd = sqlite3PagerFile(pBt->pPager))->pMethods     /* (3) */
-         && pBt->pPage1->aData[19]==0x01                       /* (5) */
+         && 0==sqlite3PagerUseWal(pBt->pPager)                 /* (5) */
          && &pBuf[-4]>=pBufStart                               /* (7) */
         ){
           u8 aSave[4];

src/pager.c

@@ -817,9 +817,10 @@ static const unsigned char aJournalMagic[] = {
 ** rollback journal. Otherwise false.
 */
 #ifndef SQLITE_OMIT_WAL
-static int pagerUseWal(Pager *pPager){
+int sqlite3PagerUseWal(Pager *pPager){
   return (pPager->pWal!=0);
 }
+# define pagerUseWal(x) sqlite3PagerUseWal(x)
 #else
 # define pagerUseWal(x) 0
 # define pagerRollbackWal(x) 0

src/pager.h

@@ -178,10 +178,13 @@ int sqlite3PagerSharedLock(Pager *pPager);
   int sqlite3PagerWalCallback(Pager *pPager);
   int sqlite3PagerOpenWal(Pager *pPager, int *pisOpen);
   int sqlite3PagerCloseWal(Pager *pPager, sqlite3*);
+  int sqlite3PagerUseWal(Pager *pPager);
 # ifdef SQLITE_ENABLE_SNAPSHOT
   int sqlite3PagerSnapshotGet(Pager *pPager, sqlite3_snapshot **ppSnapshot);
   int sqlite3PagerSnapshotOpen(Pager *pPager, sqlite3_snapshot *pSnapshot);
 # endif
+#else
+# define sqlite3PagerUseWal(x) 0
 #endif
 
 #ifdef SQLITE_ENABLE_ZIPVFS