From: drh <>
Date: Fri, 8 Jul 2022 20:03:41 +0000 (+0000)
Subject: Performance optimizations in the WHERE clause processing of the query planner.
X-Git-Tag: version-3.40.0~323
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=74879e137dbece78055a6c1a356a7d81f5b34f18;p=thirdparty%2Fsqlite.git

Performance optimizations in the WHERE clause processing of the query planner.

FossilOrigin-Name: 50c8e8de52a6ba328bc9eb38e1a67033b643ddf41ff507d2240e97e0072b6db3
---

diff --git a/manifest b/manifest
index 1708bee800..a74381f053 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Omit\san\sunnecessary\sstructure\sinitialization\sin\swhereLoopAddAll(),\sreplacing\nit\swith\san\sassert()\sto\sshow\sthat\sthe\sinitialization\shas\salready\soccurred,\sfor\na\ssmall\sperformance\sincrease\sand\ssize\sreduction.
-D 2022-07-08T18:23:04.754
+C Performance\soptimizations\sin\sthe\sWHERE\sclause\sprocessing\sof\sthe\squery\splanner.
+D 2022-07-08T20:03:41.347
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -657,7 +657,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 0f34033977b2275793c4330b2ebc3fa180a1baee06591cbc8f6e0d7aaa37988d
 F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
-F src/where.c 54e534ef371b26ac9e4955a35fbefb368fad6ed3cf10abf3a5d748bbaf7f992b
+F src/where.c 5af9a9773a3bb84acf4eac8b92b7951b780ece1dca914223f78effc4effeca2d
 F src/whereInt.h b48ca529ffe293c18cbfa8326af18a09e39910de66fb3e96ef788c7cbf8ef3a7
 F src/wherecode.c 0b09abfcb88c61c6a6984a3e065786631ff35495e9bdf865e6b74ab0a1299c5b
 F src/whereexpr.c 55a39f42aaf982574fbf52906371a84cceed98a994422198dfd03db4fce4cc46
@@ -1979,8 +1979,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 64d2312c121e3dabbc1f86effe9dfc57915395466ea2c3746821848f743b8d8f
-R 8acd37a15a19ed816e7bea6945b5086b
+P 27be9e963459ca0b20c339264125e175550debf50fdbec7d78412768a6326b42
+R b437fa10f8f11540296768d07008e6e8
 U drh
-Z d803b380ec1c17178dfbac162011dfa0
+Z 9a58f65092cc6ff74de4cfec7aa43ed3
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 2f09d2a86d..4227294a2f 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-27be9e963459ca0b20c339264125e175550debf50fdbec7d78412768a6326b42
\ No newline at end of file
+50c8e8de52a6ba328bc9eb38e1a67033b643ddf41ff507d2240e97e0072b6db3
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index 14a8278329..405811a566 100644
--- a/src/where.c
+++ b/src/where.c
@@ -2196,12 +2196,18 @@ static void whereLoopClearUnion(sqlite3 *db, WhereLoop *p){
 }
 
 /*
-** Deallocate internal memory used by a WhereLoop object
+** Deallocate internal memory used by a WhereLoop object.  Leave the
+** object in an initialized state, as if it had been newly allocated.
 */
 static void whereLoopClear(sqlite3 *db, WhereLoop *p){
-  if( p->aLTerm!=p->aLTermSpace ) sqlite3DbFreeNN(db, p->aLTerm);
+  if( p->aLTerm!=p->aLTermSpace ){
+    sqlite3DbFreeNN(db, p->aLTerm);
+    p->aLTerm = p->aLTermSpace;
+    p->nLSlot = ArraySize(p->aLTermSpace);
+  }
   whereLoopClearUnion(db, p);
-  whereLoopInit(p);
+  p->nLTerm = 0;
+  p->wsFlags = 0;
 }
 
 /*
@@ -2225,7 +2231,9 @@ static int whereLoopResize(sqlite3 *db, WhereLoop *p, int n){
 */
 static int whereLoopXfer(sqlite3 *db, WhereLoop *pTo, WhereLoop *pFrom){
   whereLoopClearUnion(db, pTo);
-  if( whereLoopResize(db, pTo, pFrom->nLTerm) ){
+  if( pFrom->nLTerm > pTo->nLSlot
+   && whereLoopResize(db, pTo, pFrom->nLTerm)
+  ){
     memset(pTo, 0, WHERE_LOOP_XFER_SZ);
     return SQLITE_NOMEM_BKPT;
   }
@@ -2878,7 +2886,11 @@ static int whereLoopAddBtreeIndex(
     pNew->u.btree.nBtm = saved_nBtm;
     pNew->u.btree.nTop = saved_nTop;
     pNew->nLTerm = saved_nLTerm;
-    if( whereLoopResize(db, pNew, pNew->nLTerm+1) ) break; /* OOM */
+    if( pNew->nLTerm>=pNew->nLSlot
+     && whereLoopResize(db, pNew, pNew->nLTerm+1)
+    ){
+       break; /* OOM while trying to enlarge the pNew->aLTerm array */
+    }
     pNew->aLTerm[pNew->nLTerm++] = pTerm;
     pNew->prereq = (saved_prereq | pTerm->prereqRight) & ~pNew->maskSelf;
 
@@ -4178,8 +4190,8 @@ static int whereLoopAddAll(WhereLoopBuilder *pBuilder){
   /* Verify that pNew has already been initialized */
   assert( pNew->nLTerm==0 );
   assert( pNew->wsFlags==0 );
-  assert( pNew->nLSlot==ArraySize(pNew->aLTermSpace) );
-  assert( pNew->aLTerm==pNew->aLTermSpace );
+  assert( pNew->nLSlot>=ArraySize(pNew->aLTermSpace) );
+  assert( pNew->aLTerm!=0 );
 
   pBuilder->iPlanLimit = SQLITE_QUERY_PLANNER_LIMIT;
   for(iTab=0, pItem=pTabList->a; pItem<pEnd; iTab++, pItem++){