From: drh <drh@noemail.net>
Date: Mon, 14 May 2018 18:09:20 +0000 (+0000)
Subject: The restriction on using automatic indexes for low cardinality loops only
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fheads%2Fexp-indexed-clause;p=thirdparty%2Fsqlite.git

The restriction on using automatic indexes for low cardinality loops only
applies if the cardinality is restricted by a LIMIT clause.

FossilOrigin-Name: 991a76bf427ade0059a3308454ebf1e7908bf959619752a13fbb3d41b4b0a162
---

diff --git a/manifest b/manifest
index 0b189b188e..9a3b2b1cc8 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Experimental\ssyntax\senhancement\sfor\san\s"INDEXED"\skeyword\sfollowing\sa\sFROM-clause\nsubquery\sthat\sindicates\sthat\san\sautomatic\sindex\son\sthat\ssubquery\sis\ssuggested.
-D 2018-05-14T17:12:42.068
+C The\srestriction\son\susing\sautomatic\sindexes\sfor\slow\scardinality\sloops\sonly\napplies\sif\sthe\scardinality\sis\srestricted\sby\sa\sLIMIT\sclause.
+D 2018-05-14T18:09:20.470
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in bfc40f350586923e0419d2ea4b559c37ec10ee4b6e210e08c14401f8e340f0da
@@ -577,7 +577,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c aa9cffc7a2bad6b826a86c8562dd4978398720ed41cb8ee7aa9d054eb8b456a0
 F src/wal.h 8de5d2d3de0956d6f6cb48c83a4012d5f227b8fe940f3a349a4b7e85ebcb492a
 F src/walker.c da987a20d40145c0a03c07d8fefcb2ed363becc7680d0500d9c79915591f5b1f
-F src/where.c ebc86f315ef2fdb4a05780f95ce981b965ecc0127ef23851c58d41bb23ccdba9
+F src/where.c 95b25ef0854c62fb6cd0bcd1950e257c28ca18f1cae094693e7da18df7ccc3fa
 F src/whereInt.h cbae2bcd37cfebdb7812a8b188cdb19634ced2b9346470d1c270556b0c33ea53
 F src/wherecode.c 728c7f70731430ccdac807a79969873e1af6968bf1c4745dff3f9dd35f636cc8
 F src/whereexpr.c e90b2e76dcabc81edff56633bf281bc01d93b71e0c81482dc06925ce39f5844a
@@ -1728,10 +1728,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P fd8b8c4196d3f0f6cb129f43ebf473ada86eefdf16181fa70ceee21e1232b5e1
-R 611d7b41a8fe4b803c387fc5e28a4594
-T *branch * exp-indexed-clause
-T *sym-exp-indexed-clause *
-T -sym-trunk *
+P 32b3d1105074529548627dcd63e25fbec6ba5e453b00e03f31ab2e324cf7f38d
+R 53348ecfc5d8e2bfe914b6f08dc1a047
 U drh
-Z 29c7f5f19fc1378727bec6e3ea350831
+Z 46884902f133074c4e29da96f2c0895f
diff --git a/manifest.uuid b/manifest.uuid
index f5bf0c5e83..358e7d8ca1 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-32b3d1105074529548627dcd63e25fbec6ba5e453b00e03f31ab2e324cf7f38d
\ No newline at end of file
+991a76bf427ade0059a3308454ebf1e7908bf959619752a13fbb3d41b4b0a162
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index cf16fe08c7..14f6472e6b 100644
--- a/src/where.c
+++ b/src/where.c
@@ -4005,9 +4005,12 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
 
         if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
         if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
-        if( (pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0 && pFrom->nRow<10 ){
+        if( (pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0
+         && (pWInfo->wctrlFlags & WHERE_USE_LIMIT)!=0
+         && pWInfo->iLimit<10
+        ){
           /* Do not use an automatic index if the this loop is expected
-          ** to run less than 2 times. */
+          ** to run less than twice due to a LIMIT clause. */
           assert( 10==sqlite3LogEst(2) );
           continue;
         }