Performance improvement in sqlite3BtreeNext() and sqlite3BtreePrevious()

for the common case of a valid cursor.

FossilOrigin-Name: dc65ad8c4c67b21e3b042b8df6580d02b634a90b

diff --git a/manifest b/manifest
index 5d4cc1099d691aded91207ead9cb8db02a2a1e4f..917de0a385a5ce1d39eba04302da5a9e1d6d1992 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Initialize\sa\svariable\sin\sfts3_write.c\son\sthe\sgrounds\sthat\sthe\sargument\srequired\sto\sshow\sthat\sit\sdoes\snot\srequire\sinitialization\swith\sis\scomplicated.\sAdd\san\sassert()\sto\swhere.c\sto\ssilence\sa\sclang\sscan-build\swarning.
-D 2013-08-19T19:29:50.054
+C Performance\simprovement\sin\ssqlite3BtreeNext()\sand\ssqlite3BtreePrevious()\nfor\sthe\scommon\scase\sof\sa\svalid\scursor.
+D 2013-08-19T20:04:10.623
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 5e41da95d92656a5004b03d3576e8b226858a28e
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -163,7 +163,7 @@ F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
 F src/backup.c 43b348822db3e4cef48b2ae5a445fbeb6c73a165
 F src/bitvec.c 19a4ba637bd85f8f63fc8c9bae5ade9fb05ec1cb
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
-F src/btree.c 9b985e4f334a1b3df5733e2ac2de1de9bdd41be7
+F src/btree.c 78287b3012fe65fd5e38927d40c01e01a783e016
 F src/btree.h bfe0e8c5759b4ec77b0d18390064a6ef3cdffaaf
 F src/btreeInt.h eecc84f02375b2bb7a44abbcbbe3747dde73edb2
 F src/build.c f99a715ff9290996b579d5e1ec8e94239dc9ae5e
@@ -1105,7 +1105,7 @@ F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
 F tool/wherecosttest.c f407dc4c79786982a475261866a161cd007947ae
 F tool/win/sqlite.vsix 97894c2790eda7b5bce3cc79cb2a8ec2fde9b3ac
-P 6acf728100ff339e4451bcefd3a20fd5c3cfd662
-R 04d95b1d185bb312b5df2b1601ef3c41
-U dan
-Z 961c1b76543606f34c9568d704cceb59
+P d6c4d48a002a6d7057fccc30064ce0b049678f0c
+R 5570190c517979d35e3b41a2553566a9
+U drh
+Z 8413b4240dd170b2f74e62b701d0cb1c

diff --git a/manifest.uuid b/manifest.uuid
index ae9db452cb0bc37b02f1be8e173cc69e79ca8f61..7c9d48de8c18fca41821458db7d2f0085663b227 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d6c4d48a002a6d7057fccc30064ce0b049678f0c
\ No newline at end of file
+dc65ad8c4c67b21e3b042b8df6580d02b634a90b
\ No newline at end of file

diff --git a/src/btree.c b/src/btree.c
index ac0a8cf2c0becd9c0f95f5425850d0f5797f49cb..bf679cd1f7087c6bc7c8704fac51fdea54b86746 100644 (file)
--- a/src/btree.c
+++ b/src/btree.c
@@ -4796,21 +4796,25 @@ int sqlite3BtreeNext(BtCursor *pCur, int *pRes){
   MemPage *pPage;
 
   assert( cursorHoldsMutex(pCur) );
-  rc = restoreCursorPosition(pCur);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
   assert( pRes!=0 );
-  if( CURSOR_INVALID==pCur->eState ){
-    *pRes = 1;
-    return SQLITE_OK;
+  if( pCur->eState!=CURSOR_VALID ){
+    rc = restoreCursorPosition(pCur);
+    if( rc!=SQLITE_OK ){
+      return rc;
+    }
+    if( CURSOR_INVALID==pCur->eState ){
+      *pRes = 1;
+      return SQLITE_OK;
+    }
   }
-  if( pCur->skipNext>0 ){
+  if( pCur->skipNext ){
+    if( pCur->skipNext>0 ){
+      pCur->skipNext = 0;
+      *pRes = 0;
+      return SQLITE_OK;
+    }
     pCur->skipNext = 0;
-    *pRes = 0;
-    return SQLITE_OK;
   }
-  pCur->skipNext = 0;
 
   pPage = pCur->apPage[pCur->iPage];
   idx = ++pCur->aiIdx[pCur->iPage];
@@ -4870,21 +4874,25 @@ int sqlite3BtreePrevious(BtCursor *pCur, int *pRes){
   MemPage *pPage;
 
   assert( cursorHoldsMutex(pCur) );
-  rc = restoreCursorPosition(pCur);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
   pCur->atLast = 0;
-  if( CURSOR_INVALID==pCur->eState ){
-    *pRes = 1;
-    return SQLITE_OK;
+  if( pCur->eState!=CURSOR_VALID ){
+    if( ALWAYS(pCur->eState>=CURSOR_REQUIRESEEK) ){
+      rc = btreeRestoreCursorPosition(pCur);
+      if( rc!=SQLITE_OK ) return rc;
+    }
+    if( CURSOR_INVALID==pCur->eState ){
+      *pRes = 1;
+      return SQLITE_OK;
+    }
   }
-  if( pCur->skipNext<0 ){
+  if( pCur->skipNext ){
+    if( pCur->skipNext<0 ){
+      pCur->skipNext = 0;
+      *pRes = 0;
+      return SQLITE_OK;
+    }
     pCur->skipNext = 0;
-    *pRes = 0;
-    return SQLITE_OK;
   }
-  pCur->skipNext = 0;
 
   pPage = pCur->apPage[pCur->iPage];
   assert( pPage->isInit );