From: drh <drh@noemail.net>
Date: Mon, 6 Apr 2020 18:16:31 +0000 (+0000)
Subject: Performance improvement for column name lookup.
X-Git-Tag: version-3.32.0~86
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d44390c8c54268e1651fafb9ee738574947aceba;p=thirdparty%2Fsqlite.git

Performance improvement for column name lookup.

FossilOrigin-Name: 1e4b6a93987cdfbf829e2ff35ef417c290625f2894ad11949e301af518f1fb44
---

diff --git a/manifest b/manifest
index ffc40648fe..d18793bda0 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C When\srunning\sALTER\sTABLE,\savoid\sadding\ssome\sinternally\sgenerated\stokens\sto\sthe\stoken\smap\sto\simprove\sperformance\son\sschemas\swith\snested\sviews.
-D 2020-04-06T16:37:05.016
+C Performance\simprovement\sfor\scolumn\sname\slookup.
+D 2020-04-06T18:16:31.753
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -465,7 +465,7 @@ F spec.template 86a4a43b99ebb3e75e6b9a735d5fd293a24e90ca
 F sqlite.pc.in 42b7bf0d02e08b9e77734a47798d1a55a9e0716b
 F sqlite3.1 fc7ad8990fc8409983309bb80de8c811a7506786
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
-F src/alter.c ac9d737cace62b5cd88bff5310e53e299bc0919f08b5934a2bd0f8e8e65d770e
+F src/alter.c db353ed3123b05730c58744e52a71711779abd8d9081e31c981b69ec42a911cc
 F src/analyze.c 831bb090988477a00d3b4c000746e1b0454dcc93b10b793e6ebe1c47f25d193a
 F src/attach.c ff2daea0fe62080192e3f262670e4f61f5a86c1e7bea9cec34e960fe79852aa1
 F src/auth.c a3d5bfdba83d25abed1013a8c7a5f204e2e29b0c25242a56bc02bb0c07bf1e06
@@ -475,7 +475,7 @@ F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
 F src/btree.c 79ce96ab39fd2fc21ff00d03913587d5a08280a9eb081a08d0ffa9fa26f4f6fb
 F src/btree.h 6111552f19ed7a40f029cf4b33badc6fef9880314fffd80a945f0b7f43ab7471
 F src/btreeInt.h dee1a1d0c621524e006bb260bd6b66d5d1867da6fe38cba9ad7b6a9bb9c0c175
-F src/build.c 3d22f21c4701f62c1a191c6b6d17552fb1b593fe9a97c0613cca05ab104a9a51
+F src/build.c ec6c0bda1e43ef55e5f5121a77ba19fac51fc6585f95ce2da795bcedcf6e8f36
 F src/callback.c d0b853dd413255d2e337b34545e54d888ea02f20da5ad0e63585b389624c4a6c
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 6a77ec9e0eb87aea929e002c816298907e337094a7b556898ae2d1e6be209f90
@@ -529,14 +529,14 @@ F src/pragma.h 9473160d220416456b40f27323bb4b316d4e4e08ffbf8bf88c5f7045d49c38e5
 F src/prepare.c 8d4d6c8aa6afefc48027c54b41cdf134b4d6bc2fc4badbe483ad7fd9e1728a28
 F src/printf.c 9be6945837c839ba57837b4bc3af349eba630920fa5532aa518816defe42a7d4
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
-F src/resolve.c bbaa078ea3546276fe34e78187dc67036de4c7d95deff2ce3784e79623a31aa5
+F src/resolve.c 4071f2576808300198b539a8839281eb7150b0b8155c3eaa9165f0253bfff6dc
 F src/rowset.c ba9515a922af32abe1f7d39406b9d35730ed65efab9443dc5702693b60854c92
-F src/select.c 7aa91ab374d83a3b8ef02859fd61de57bc23aaeefa125b6e2d2c502662f2ea42
+F src/select.c ab4eb1aee1bd066feea5b6eff264220ae54459019654264e9f688368a7d0c0b5
 F src/shell.c.in 759bb4a283651955ff2ddb104541b1805b1fff915017083bdd39975cd4e223aa
 F src/sqlite.h.in cc7d0949ac32bb68ed97acdb3e7ae91cd413a24d32d6ff049ef8308d620a4367
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 9c5269260409eb3275324ccace6a13a96f4ad330c708415f70ca6097901ff4ee
-F src/sqliteInt.h b0165686885990e29622f56b2f95b93c12c6f84be4cf1ee60797d80a0dcd7f15
+F src/sqliteInt.h 0f3848c46310d197246003f052985b72d1cdbfc0b31e069db76cb5231062fa1d
 F src/sqliteLimit.h 95cb8479ca459496d9c1c6a9f76b38aee12203a56ce1092fe13e50ae2454c032
 F src/status.c 9ff2210207c6c3b4d9631a8241a7d45ab1b26a0e9c84cb07a9b5ce2de9a3b278
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -601,7 +601,7 @@ F src/trigger.c 4ada1037cc99777f647a882cdacbd1a4deb6567b69daf02946286401b88cdc04
 F src/update.c 3eb778c42155d944377a4ee5e440b04520f07094804ed6ce63d2528f619614d9
 F src/upsert.c 2920de71b20f04fe25eb00b655d086f0ba60ea133c59d7fa3325c49838818e78
 F src/utf.c 95fb6e03a5ca679045c5adccd05380f0addccabef5911abddcb06af069500ab7
-F src/util.c a285c1e026907b69fa2592bd05047a565a1d8a1aef2b73c924b6a8ffe772871a
+F src/util.c 3b6cedf7a0c69bd6e1acce832873952d416212d6293b18d03064e07d7a9b5118
 F src/vacuum.c 813b510ba887fee6492bcb11f2bf77d7eb58b232b83649136372e0a2fc17f4b9
 F src/vdbe.c 972999395eee88702091fb5d50cf4effd07889c371807d222a7f517388e6378e
 F src/vdbe.h 51282fbe819ee0e8eeeaab176240860d334c20a12b14f3b363e7f1a4e05d60b9
@@ -1860,7 +1860,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 921448f0e24a3753374b32be9d7bf36a9ca5d8522eff9f0b51dc243f08652419
-R 315e582db187b4e17ad03b8b387a78b4
-U dan
-Z 72d22b8c17363fe4c28ed6cd6151ab27
+P 4cf8721f5ceb1fdaefdc355b3211f75c53c4cdf9d2582ca70fc96777a9b057c2
+R 21d736bf1132a719fd78a53a135a2ffc
+U drh
+Z 2d567e7c67065db6dbe909acd8dc5855
diff --git a/manifest.uuid b/manifest.uuid
index 01c1550354..76c084d972 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-4cf8721f5ceb1fdaefdc355b3211f75c53c4cdf9d2582ca70fc96777a9b057c2
\ No newline at end of file
+1e4b6a93987cdfbf829e2ff35ef417c290625f2894ad11949e301af518f1fb44
\ No newline at end of file
diff --git a/src/alter.c b/src/alter.c
index 7114757a27..b041291a25 100644
--- a/src/alter.c
+++ b/src/alter.c
@@ -469,6 +469,7 @@ void sqlite3AlterBeginAddColumn(Parse *pParse, SrcList *pSrc){
   for(i=0; i<pNew->nCol; i++){
     Column *pCol = &pNew->aCol[i];
     pCol->zName = sqlite3DbStrDup(db, pCol->zName);
+    pCol->hName = sqlite3StrIHash(pCol->zName);
     pCol->zColl = 0;
     pCol->pDflt = 0;
   }
diff --git a/src/build.c b/src/build.c
index dcd035e99d..cf36766aef 100644
--- a/src/build.c
+++ b/src/build.c
@@ -590,6 +590,7 @@ void sqlite3DeleteColumnNames(sqlite3 *db, Table *pTable){
   assert( pTable!=0 );
   if( (pCol = pTable->aCol)!=0 ){
     for(i=0; i<pTable->nCol; i++, pCol++){
+      assert( pCol->zName==0 || pCol->hName==sqlite3StrIHash(pCol->zName) );
       sqlite3DbFree(db, pCol->zName);
       sqlite3ExprDelete(db, pCol->pDflt);
       sqlite3DbFree(db, pCol->zColl);
@@ -1238,6 +1239,7 @@ void sqlite3AddColumn(Parse *pParse, Token *pName, Token *pType){
   pCol = &p->aCol[p->nCol];
   memset(pCol, 0, sizeof(p->aCol[0]));
   pCol->zName = z;
+  pCol->hName = sqlite3StrIHash(z);
   sqlite3ColumnPropertiesFromName(p, pCol);
  
   if( pType->n==0 ){
diff --git a/src/resolve.c b/src/resolve.c
index 2def65f991..5877dfa371 100644
--- a/src/resolve.c
+++ b/src/resolve.c
@@ -294,6 +294,7 @@ static int lookupName(
 
     if( pSrcList ){
       for(i=0, pItem=pSrcList->a; i<pSrcList->nSrc; i++, pItem++){
+        u8 hCol;
         pTab = pItem->pTab;
         assert( pTab!=0 && pTab->zName!=0 );
         assert( pTab->nCol>0 );
@@ -327,8 +328,9 @@ static int lookupName(
         if( 0==(cntTab++) ){
           pMatch = pItem;
         }
+        hCol = sqlite3StrIHash(zCol);
         for(j=0, pCol=pTab->aCol; j<pTab->nCol; j++, pCol++){
-          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+          if( pCol->hName==hCol && sqlite3StrICmp(pCol->zName, zCol)==0 ){
             /* If there has been exactly one prior match and this match
             ** is for the right-hand table of a NATURAL JOIN or is in a 
             ** USING clause, then skip this match.
@@ -389,10 +391,11 @@ static int lookupName(
 
       if( pTab ){ 
         int iCol;
+        u8 hCol = sqlite3StrIHash(zCol);
         pSchema = pTab->pSchema;
         cntTab++;
         for(iCol=0, pCol=pTab->aCol; iCol<pTab->nCol; iCol++, pCol++){
-          if( sqlite3StrICmp(pCol->zName, zCol)==0 ){
+          if( pCol->hName==hCol && sqlite3StrICmp(pCol->zName, zCol)==0 ){
             if( iCol==pTab->iPKey ){
               iCol = -1;
             }
diff --git a/src/select.c b/src/select.c
index ce85c91d0b..76b9827e8c 100644
--- a/src/select.c
+++ b/src/select.c
@@ -2023,6 +2023,7 @@ int sqlite3ColumnsFromExprList(
       if( cnt>3 ) sqlite3_randomness(sizeof(cnt), &cnt);
     }
     pCol->zName = zName;
+    pCol->hName = sqlite3StrIHash(zName);
     sqlite3ColumnPropertiesFromName(0, pCol);
     if( zName && sqlite3HashInsert(&ht, zName, pCol)==pCol ){
       sqlite3OomFault(db);
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index d08c7ce1e7..aaa99a43a8 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1949,6 +1949,7 @@ struct Column {
   u8 notNull;      /* An OE_ code for handling a NOT NULL constraint */
   char affinity;   /* One of the SQLITE_AFF_... values */
   u8 szEst;        /* Estimated size of value in this column. sizeof(INT)==1 */
+  u8 hName;        /* Column name hash for faster lookup */
   u16 colFlags;    /* Boolean properties.  See COLFLAG_ defines below */
 };
 
@@ -4567,6 +4568,7 @@ int sqlite3MatchEName(
   const char*
 );
 Bitmask sqlite3ExprColUsed(Expr*);
+u8 sqlite3StrIHash(const char*);
 int sqlite3ResolveExprNames(NameContext*, Expr*);
 int sqlite3ResolveExprListNames(NameContext*, ExprList*);
 void sqlite3ResolveSelectNames(Parse*, Select*, NameContext*);
diff --git a/src/util.c b/src/util.c
index 693759bffc..09520d1d62 100644
--- a/src/util.c
+++ b/src/util.c
@@ -317,6 +317,19 @@ int sqlite3_strnicmp(const char *zLeft, const char *zRight, int N){
   return N<0 ? 0 : UpperToLower[*a] - UpperToLower[*b];
 }
 
+/*
+** Compute an 8-bit hash on a string that is insensitive to case differences
+*/
+u8 sqlite3StrIHash(const char *z){
+  u8 h = 0;
+  if( z==0 ) return 0;
+  while( z[0] ){
+    h += UpperToLower[(unsigned char)z[0]];
+    z++;
+  }
+  return h;
+}
+
 /*
 ** Compute 10 to the E-th power.  Examples:  E==1 results in 10.
 ** E==2 results in 100.  E==50 results in 1.0e50.