Comment tweaks in where.c. No changes to code.

FossilOrigin-Name: cecc5fdd5d8fbad7d9e8c275b9ba9ade3dbee8ef

diff --git a/manifest b/manifest
index ed857f034afc3f6958b1a495a7ba2b9c49496d83..299b950889bf8e1e462a5b12eefb12df90c9298f 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sa\snew\sORDER\sBY\soptimization\sthat\sbypasses\sORDER\sBY\sterms\sthat\sare\nconstrained\sby\s==\sand\sIS\sNULL\sterms\sof\sthe\sWHERE\sclause.
-D 2013-06-14T02:51:48.285
+C Comment\stweaks\sin\swhere.c.\s\sNo\schanges\sto\scode.
+D 2013-06-14T13:27:01.630
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 5e41da95d92656a5004b03d3576e8b226858a28e
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -289,7 +289,7 @@ F src/vtab.c b05e5f1f4902461ba9f5fc49bb7eb7c3a0741a83
 F src/wal.c 436bfceb141b9423c45119e68e444358ee0ed35d
 F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
 F src/walker.c 4fa43583d0a84b48f93b1e88f11adf2065be4e73
-F src/where.c 7d406cca2f60afbbfb57470f0d4981798bccf6e8
+F src/where.c cd2ee239c40ef7ffc952e176bfb98ff13a638b20
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/aggerror.test a867e273ef9e3d7919f03ef4f0e8c0d2767944f2
 F test/aggnested.test 45c0201e28045ad38a530b5a144b73cd4aa2cfd6
@@ -1096,7 +1096,7 @@ F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
 F tool/wherecosttest.c f407dc4c79786982a475261866a161cd007947ae
 F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
-P ade473b5ae3fe2162b0ec29731d8e864a9301e07
-R eae0305c76446978c9d6694aa033807b
+P b920bb70bb009b7c54e7667544c9810c5ee25e19
+R 382f7260a0330db641dd26f80cde0534
 U drh
-Z 288ef6a3a068d55d460d1b487a44477a
+Z 568b215d3c8e178d6fdb12bf215bc7ae

diff --git a/manifest.uuid b/manifest.uuid
index ade080fb5234ab4d11e9b20dc61d71cd2148f443..6a7fb20d1e9bb661700902c3e960264c3e0140f7 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-b920bb70bb009b7c54e7667544c9810c5ee25e19
\ No newline at end of file
+cecc5fdd5d8fbad7d9e8c275b9ba9ade3dbee8ef
\ No newline at end of file

diff --git a/src/where.c b/src/where.c
index 2163ee7a56183d3adedaec5341d15b97fb8c656d..33370c383faaa892ea188e9fe8b7c8a734806511 100644 (file)
--- a/src/where.c
+++ b/src/where.c
@@ -65,7 +65,7 @@ typedef struct WhereScan WhereScan;
 typedef unsigned short int WhereCost;
 
 /*
-** This object contains information needed to implement a single nestd
+** This object contains information needed to implement a single nested
 ** loop in WHERE clause.
 **
 ** Contrast this object with WhereLoop.  This object describes the
@@ -5944,12 +5944,10 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
       }
     }
 
-    /* If this scan uses an index, make code substitutions to read data
-    ** from the index in preference to the table. Sometimes, this means
-    ** the table need never be read from. This is a performance boost,
-    ** as the vdbe level waits until the table is read before actually
-    ** seeking the table cursor to the record corresponding to the current
-    ** position in the index.
+    /* If this scan uses an index, make VDBE code substitutions to read data
+    ** from the index instead of from the table where possible.  In some cases
+    ** this optimization prevents the table from ever being read, which can
+    ** yield a significant performance boost.
     ** 
     ** Calls to the code generator in between sqlite3WhereBegin and
     ** sqlite3WhereEnd will have created code that references the table