From: drh <drh@noemail.net>
Date: Fri, 25 Aug 2017 13:34:18 +0000 (+0000)
Subject: Small performance optimization in sqlite3WhereBegin().
X-Git-Tag: version-3.21.0~124
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=83e8ca54d1f09db06ecc30687a16cbdcf7b29250;p=thirdparty%2Fsqlite.git

Small performance optimization in sqlite3WhereBegin().

FossilOrigin-Name: 39f708d1e286931365a8992dbe7f900108ff1dad146032a284ad1dec09b11e06
---

diff --git a/manifest b/manifest
index 5d2eb2a992..e7c1f7c289 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Convert\sa\sbranch\smade\sunreachable\sby\s[59560d07]\sinto\san\sassert().
-D 2017-08-25T13:02:48.882
+C Small\sperformance\soptimization\sin\ssqlite3WhereBegin().
+D 2017-08-25T13:34:18.937
 F Makefile.in c644bbe8ebe4aae82ad6783eae6b6beea4c727b99ff97568b847ced5e2ac7afb
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 25b154da7f0b3d4924f27378c1f8d006285b80811f1ccf3ed953dbebf6282136
@@ -538,7 +538,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 839db09792fead5052bb35e533fa485e134913d547d05b5f42e537b73e63f07a
 F src/wal.h 8de5d2d3de0956d6f6cb48c83a4012d5f227b8fe940f3a349a4b7e85ebcb492a
 F src/walker.c 3ccfa8637f95355bff61144e01a615b8ef26f79c312880848da73f03367da1e6
-F src/where.c ad558533d6fe6578857635218633aa241e2428835763c46801be9e68d6ec0701
+F src/where.c 0aaa1b085a018c1c2e2da367b48491ce2686aea351bd17772c46b7e04eb51e3d
 F src/whereInt.h 93bb90b77d39901eda31b44d8e90da1351193ccfe96876f89b58a93a33b84c3d
 F src/wherecode.c e7be3b7f4c11908500cdf02b299d190d3742659533f58e0f4047962fdb5a48da
 F src/whereexpr.c fe1fe600d7334e91f3d9d487021362d543fba8ab2f1be5e0d68063d619379c05
@@ -1651,7 +1651,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P e8d23afe8478e42779ec1dd602ca2d77d4f3c26c4d54f52112c5aaa928536538
-R c47094d13357cf3081b589cea406d444
+P 2738b8db3caa6ce48d27cb5749d27b79241e6f6682b694886f6ef663e5443583
+R be107142fb32b5eeca2b38bf38398332
 U drh
-Z 0c1347313e1f31701f169aeedc1bd394
+Z ca59cf9901a72073d38774a5b3f91248
diff --git a/manifest.uuid b/manifest.uuid
index 27c4e54395..1cc2968043 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-2738b8db3caa6ce48d27cb5749d27b79241e6f6682b694886f6ef663e5443583
\ No newline at end of file
+39f708d1e286931365a8992dbe7f900108ff1dad146032a284ad1dec09b11e06
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index 5402977c30..d414b936d5 100644
--- a/src/where.c
+++ b/src/where.c
@@ -4537,37 +4537,38 @@ WhereInfo *sqlite3WhereBegin(
     if( wctrlFlags & WHERE_WANT_DISTINCT ){
       pWInfo->eDistinct = WHERE_DISTINCT_UNIQUE;
     }
-  }
-
-  /* Assign a bit from the bitmask to every term in the FROM clause.
-  **
-  ** The N-th term of the FROM clause is assigned a bitmask of 1<<N.
-  **
-  ** The rule of the previous sentence ensures thta if X is the bitmask for
-  ** a table T, then X-1 is the bitmask for all other tables to the left of T.
-  ** Knowing the bitmask for all tables to the left of a left join is
-  ** important.  Ticket #3015.
-  **
-  ** Note that bitmasks are created for all pTabList->nSrc tables in
-  ** pTabList, not just the first nTabList tables.  nTabList is normally
-  ** equal to pTabList->nSrc but might be shortened to 1 if the
-  ** WHERE_OR_SUBCLAUSE flag is set.
-  */
-  for(ii=0; ii<pTabList->nSrc; ii++){
-    createMask(pMaskSet, pTabList->a[ii].iCursor);
-    sqlite3WhereTabFuncArgs(pParse, &pTabList->a[ii], &pWInfo->sWC);
-  }
-#ifdef SQLITE_DEBUG
-  {
-    Bitmask mx = 0;
-    for(ii=0; ii<pTabList->nSrc; ii++){
-      Bitmask m = sqlite3WhereGetMask(pMaskSet, pTabList->a[ii].iCursor);
-      assert( m>=mx );
-      mx = m;
+  }else{
+    /* Assign a bit from the bitmask to every term in the FROM clause.
+    **
+    ** The N-th term of the FROM clause is assigned a bitmask of 1<<N.
+    **
+    ** The rule of the previous sentence ensures thta if X is the bitmask for
+    ** a table T, then X-1 is the bitmask for all other tables to the left of T.
+    ** Knowing the bitmask for all tables to the left of a left join is
+    ** important.  Ticket #3015.
+    **
+    ** Note that bitmasks are created for all pTabList->nSrc tables in
+    ** pTabList, not just the first nTabList tables.  nTabList is normally
+    ** equal to pTabList->nSrc but might be shortened to 1 if the
+    ** WHERE_OR_SUBCLAUSE flag is set.
+    */
+    ii = 0;
+    do{
+      createMask(pMaskSet, pTabList->a[ii].iCursor);
+      sqlite3WhereTabFuncArgs(pParse, &pTabList->a[ii], &pWInfo->sWC);
+    }while( (++ii)<pTabList->nSrc );
+  #ifdef SQLITE_DEBUG
+    {
+      Bitmask mx = 0;
+      for(ii=0; ii<pTabList->nSrc; ii++){
+        Bitmask m = sqlite3WhereGetMask(pMaskSet, pTabList->a[ii].iCursor);
+        assert( m>=mx );
+        mx = m;
+      }
     }
+  #endif
   }
-#endif
-
+  
   /* Analyze all of the subexpressions. */
   sqlite3WhereExprAnalyze(pTabList, &pWInfo->sWC);
   if( db->mallocFailed ) goto whereBeginError;