(no comment)

FossilOrigin-Name: 263293f1e6db26039d94c9ed7efa2cdea25df5e5f42673a116ce2d03b9fadff4

manifest

@@ -1,5 +1,5 @@
-C Import\sfurther\scorner-case\sfixes\sfor\sthe\sin-scan-vs-index\sor\sOP_SeekScan\noptimization\sfrom\strunk.
+C (no\scomment)
-D 2020-10-02T13:57:13.021
+D 2020-10-22T18:58:33.187
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -453,7 +453,7 @@ F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 fc7ad8990fc8409983309bb80de8c811a7506786
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
 F src/alter.c d8f927946f25d6a39a344e18db52d1ca492ce561e9b8c4b985fc580bc050bb93
-F src/analyze.c 58db66344a5c58dcabb57f26696f6f2993956c830446da40b444051d2fdaf644
+F src/analyze.c eb5fae655948660f84c270ca4fd553fa482f9e51af8d45ab4653be69819f0fea
 F src/attach.c 78e986baee90cb7b83fb9eafa79c22581a8ada14030fd633b0683c95cf11213c
 F src/auth.c 0fac71038875693a937e506bceb492c5f136dd7b1249fbd4ae70b4e8da14f9df
 F src/backup.c 78d3cecfbe28230a3a9a1793e2ead609f469be43e8f486ca996006be551857ab
@@ -523,7 +523,7 @@ F src/shell.c.in c1986496062f9dba4ed5b70db06b5e0f32e1954cdcfab0b30372c6c18679681
 F src/sqlite.h.in 59f5e145b8d7a915ca29c6bf4a1f00e3112c1605c9ac5c627c45060110332ba2
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 9ecc93b8493bd20c0c07d52e2ac0ed8bab9b549c7f7955b59869597b650dd8b5
-F src/sqliteInt.h 34fb4aa27d7f172805a8be51a826bafe05138ea604329bb91886516c4ca6e6b7
+F src/sqliteInt.h e19d89d6a1c24cded45b39f4bd9249c0222ded77681576675f91f035aca769c6
 F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
 F src/status.c 46e7aec11f79dad50965a5ca5fa9de009f7d6bde08be2156f1538a0a296d4d0e
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -604,7 +604,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 9eccc7ebb532a7b0fd3cabc16cff576b9afa763472272db67d84fb8cec96f5c0
 F src/wal.h 606292549f5a7be50b6227bd685fa76e3a4affad71bb8ac5ce4cb5c79f6a176a
 F src/walker.c 7607f1a68130c028255d8d56094ea602fc402c79e1e35a46e6282849d90d5fe4
-F src/where.c 9030f0f4d674d9099932ed7913eb1f8ddd58acc6cfea893deec7efa76fc44d13
+F src/where.c d0feda2eb597cba0a1de3fd2a69e4c46fb641257b076602fbd3b289700854efd
 F src/whereInt.h bcbba483d0cd72c17ab9af97061dce3c00eb3695cd17a5d41cdfec2cb5a6e8ce
 F src/wherecode.c 5e0b6dec8591e13f1f0af828d350e4a5dd2e3518b63d328f21bb38e2456dfeb7
 F src/whereexpr.c 90859652920f153d2c03f075488744be2926625ebd36911bcbcb17d0d29c891c
@@ -1315,7 +1315,7 @@ F test/sidedelete.test f0ad71abe6233e3b153100f3b8d679b19a488329
 F test/skipscan1.test b1fef3046d555836712d4a3a7c8ae8193356c6a15bee59cb3976e4ee98596c97
 F test/skipscan2.test 3eb703ce794f139e7b83567911046298bcde29606116727f9b700ce34f559d2d
 F test/skipscan3.test ec5bab3f81c7038b43450e7b3062e04a198bdbb5
-F test/skipscan5.test 67817a4b6857c47e0e33ba3e506da6f23ef68de2
+F test/skipscan5.test 980875ad45d8aacfe7bdec7c288343520cd1d14e84befdcfe50c785f9e6c8709
 F test/skipscan6.test 0b4cd1b4ac9f84d91454df513c99a4932fa07e8f27b8049bea605068b3e34ac7
 F test/snapshot.test a504f2e7009f512ef66c719f0ea1c55a556bdaf1e1312c80a04d46fc1a3e9632
 F test/snapshot2.test 8d6ff5dd9cc503f6e12d408a30409c3f9c653507b24408d9cd7195931c89bc54
@@ -1669,7 +1669,7 @@ F test/whereC.test cae295158703cb3fc23bf1a108a9ab730efff0f6
 F test/whereD.test 711d4df58d6d4fb9b3f5ce040b818564198be002
 F test/whereE.test b3a055eef928c992b0a33198a7b8dc10eea5ad2f
 F test/whereF.test 3d9412b1199d3e2bed34fcb76b4c48d0bf4df95d27e3f8dd27b6f8b4716d0d89
-F test/whereG.test 0158783235a6dd82fc0e37652b8522b186b9510594ac0a4bff0c4101b4396a52
+F test/whereG.test 3ceb63370bf96d0ebc8b5589b5efbaab6506bea86ad7b481a2ecf241378ed9a1
 F test/whereH.test e4b07f7a3c2f5d31195cd33710054c78667573b2
 F test/whereI.test a2874062140ed4aba9ffae76e6190a3df6fc73d1373fdfa8fd632945082a5364
 F test/whereJ.test 88287550f6ee604422403b053455b1ad894eeaa5c35d348532dfa1439286cb9a
@@ -1819,9 +1819,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P ec37744c6ea61f94bb850875f9ac86e80ac0c111bc5a2c2eb2050897ec1e63cd
+P c144d6404ff122d6a92d59fed09fab9a0a592e4dab771ef41b0db3535359f1d6
-Q +ad5ab24ebd557e7af1d92ab3fbcb3747c04da5ad4ed779fb6391dc94042687dd
+Q +0e7e113d9f2c929c1f8a85e2cfad8e2e60f0e8770212b5e5320fb2a2c42911f8
-Q +c0400f8c0bcb85ba39004feff753eae2f8e82065539e52b5788febd7644c417b
+R 4ca1a3da910bf98bc6e4950d0ce095f1
-R ed40b319cb8ff5e5e2a58c08d4ee2c80
 U drh
-Z 61ad1955920a3fa1588d272c2f0c8015
+Z 0bf840746e1be7de2c0bb7a051dce63e

manifest.uuid

@@ -1 +1 @@
-c144d6404ff122d6a92d59fed09fab9a0a592e4dab771ef41b0db3535359f1d6
+263293f1e6db26039d94c9ed7efa2cdea25df5e5f42673a116ce2d03b9fadff4

src/analyze.c

@@ -1756,6 +1756,7 @@ static int loadStatTbl(
     }
     pSpace = (tRowcnt*)&pIdx->aSample[nSample];
     pIdx->aAvgEq = pSpace; pSpace += nIdxCol;
+    pIdx->pTable->tabFlags |= TF_HasStat4;
     for(i=0; i<nSample; i++){
       pIdx->aSample[i].anEq = pSpace; pSpace += nIdxCol;
       pIdx->aSample[i].anLt = pSpace; pSpace += nIdxCol;

src/sqliteInt.h

@@ -2011,6 +2011,7 @@ struct Table {
                                      ** Index.aiRowLogEst[] values */
 #define TF_HasNotNull      0x0200    /* Contains NOT NULL constraints */
 #define TF_Shadow          0x0400    /* True for a shadow table */
+#define TF_HasStat4        0x2000    /* STAT4 info available for this table */
 
 /*
 ** Test to see whether or not a table is a virtual table.  This is

src/where.c

@@ -2997,8 +2997,23 @@ static int whereLoopAddBtree(
 
       /* Full table scan */
       pNew->iSortIdx = b ? iSortIdx : 0;
-      /* TUNING: Cost of full table scan is (N*3.0). */
+      /* TUNING: Cost of full table scan is 3.0*N.  The 3.0 factor is an
+      ** extra cost designed to discourage the use of full table scans,
+      ** since index lookups have better worst-case performance if our
+      ** stat guesses are wrong.  Reduce the 3.0 penalty slightly
+      ** (to 2.75) if we have valid STAT4 information for the table.
+      ** At 2.75, a full table scan is preferred over using an index on
+      ** a column with just two distinct values where each value has about
+      ** an equal number of appearances.  Without STAT4 data, we still want
+      ** to use an index in that case, since the constraint might be for
+      ** the scarcer of the two values, and in that case an index lookup is
+      ** better.
+      */
+#ifdef SQLITE_ENABLE_STAT4
+      pNew->rRun = rSize + 16 - 2*((pTab->tabFlags & TF_HasStat4)!=0);
+#else
       pNew->rRun = rSize + 16;
+#endif
       ApplyCostMultiplier(pNew->rRun, pTab->costMult);
       whereLoopOutputAdjust(pWC, pNew, rSize);
       rc = whereLoopInsert(pBuilder, pNew);

test/skipscan5.test

@@ -30,7 +30,7 @@ do_execsql_test 1.1 {
 
 expr srand(4)
 do_test 1.2 {
-  for {set i 0} {$i < 100} {incr i} {
+  for {set i 0} {$i < 1000} {incr i} {
     set a [expr int(rand()*4.0) + 1]
     set b [expr int(rand()*20.0) + 1]
     execsql { INSERT INTO t1 VALUES($a, $b, NULL) }
@@ -43,7 +43,7 @@ foreach {tn q res} {
   2  "b > 12 AND b < 16"       {/*ANY(a) AND b>? AND b<?*/}
   3  "b > 2 AND b < 16"        {/*SCAN TABLE t1*/}
   4  "b > 18 AND b < 25"       {/*ANY(a) AND b>? AND b<?*/}
-  5  "b > 15"                  {/*ANY(a) AND b>?*/}
+  5  "b > 16"                  {/*ANY(a) AND b>?*/}
   6  "b > 5"                   {/*SCAN TABLE t1*/}
   7  "b < 15"                  {/*SCAN TABLE t1*/}
   8  "b < 5"                   {/*ANY(a) AND b<?*/}
@@ -52,7 +52,7 @@ foreach {tn q res} {
   11 "b > '12' AND b < '16'"   {/*ANY(a) AND b>? AND b<?*/}
   12 "b > '2' AND b < '16'"    {/*SCAN TABLE t1*/}
   13 "b > '18' AND b < '25'"   {/*ANY(a) AND b>? AND b<?*/}
-  14 "b > '15'"                {/*ANY(a) AND b>?*/}
+  14 "b > '16'"                {/*ANY(a) AND b>?*/}
   15 "b > '5'"                 {/*SCAN TABLE t1*/}
   16 "b < '15'"                {/*SCAN TABLE t1*/}
   17 "b < '5'"                 {/*ANY(a) AND b<?*/}
@@ -108,7 +108,7 @@ foreach {tn dbenc coll} {
     3 { c > 'q' }                     {/*ANY(a) AND ANY(b) AND c>?*/}
     4 { c > 'e' }                     {/*SCAN TABLE t2*/}
     5 { c < 'q' }                     {/*SCAN TABLE t2*/}
-    6 { c < 'c' }                     {/*ANY(a) AND ANY(b) AND c<?*/}
+    6 { c < 'b' }                     {/*ANY(a) AND ANY(b) AND c<?*/}
   } {
     set sql "EXPLAIN QUERY PLAN SELECT * FROM t2 WHERE $q" 
     do_execsql_test 2.$tn.$tn2 $sql $res

test/whereG.test

@@ -220,9 +220,15 @@ do_eqp_test 5.2.4 {
   SELECT * FROM t1 WHERE likely(b>?)
 } {SCAN TABLE t1}
 
-do_eqp_test 5.3.1 {
+ifcapable stat4 {
-  SELECT * FROM t1 WHERE a=?
+  do_eqp_test 5.3.1.stat4 {
-} {SEARCH TABLE t1 USING INDEX i1 (a=?)}
+    SELECT * FROM t1 WHERE a=?
+  } {SCAN TABLE t1}
+} else {
+  do_eqp_test 5.3.1 {
+    SELECT * FROM t1 WHERE a=?
+  } {SEARCH TABLE t1 USING INDEX i1}
+}
 do_eqp_test 5.3.2 {
   SELECT * FROM t1 WHERE likelihood(a=?, 0.9)
 } {SCAN TABLE t1}