From: drh <drh@noemail.net>
Date: Tue, 23 Sep 2014 22:36:25 +0000 (+0000)
Subject: Avoid calling btreeParseCellPtr() from within fillInCell() since most of
X-Git-Tag: version-3.8.7~78
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6200c88123e5933dc81ec132d0c03f8bff86a07b;p=thirdparty%2Fsqlite.git

Avoid calling btreeParseCellPtr() from within fillInCell() since most of
what btreeParseCellPtr() computes is ignored by fillInCell().  Instead, have
fillInCell() compute the values it needs inline.  Performance improvement.

FossilOrigin-Name: 4147f6671e3faa8ddffab8387a6c7d9b5b962fc8
---

diff --git a/manifest b/manifest
index 70db7cda92..2923bfbe6d 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Simplify\sthe\sCellInfo\sstructure\sfor\sa\ssize\sreduction\sand\sperformance\nimprovement.
-D 2014-09-23T21:25:19.710
+C Avoid\scalling\sbtreeParseCellPtr()\sfrom\swithin\sfillInCell()\ssince\smost\sof\nwhat\sbtreeParseCellPtr()\scomputes\sis\signored\sby\sfillInCell().\s\sInstead,\shave\nfillInCell()\scompute\sthe\svalues\sit\sneeds\sinline.\s\sPerformance\simprovement.
+D 2014-09-23T22:36:25.858
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in cf57f673d77606ab0f2d9627ca52a9ba1464146a
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -172,7 +172,7 @@ F src/auth.c d8abcde53426275dab6243b441256fcd8ccbebb2
 F src/backup.c a31809c65623cc41849b94d368917f8bb66e6a7e
 F src/bitvec.c 19a4ba637bd85f8f63fc8c9bae5ade9fb05ec1cb
 F src/btmutex.c 49ca66250c7dfa844a4d4cb8272b87420d27d3a5
-F src/btree.c 2a7c67d474624732612f97a89e34cf85f8cd4905
+F src/btree.c 11cf36074a9829bad4506e8486bfd2431168bb54
 F src/btree.h a79aa6a71e7f1055f01052b7f821bd1c2dce95c8
 F src/btreeInt.h a5a869ec2c3e56ee9e214ee748d7942716be0340
 F src/build.c 8dbca25988045fbf2a33c9631c42706fa6449e60
@@ -1200,7 +1200,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P d2962a5f388f30a02429e0c8b87399f482b5604c
-R 3633e95932853227476c5d6e8f02e193
+P bf59df66b3613c38cfb13a68091b8328ebb22c78
+R 7c25e7d21782a499afecd58eb6881944
 U drh
-Z 6131f39965fefa27be7e69636d8311d7
+Z 9128d4e264c0fc76a3ba82d24c937cbe
diff --git a/manifest.uuid b/manifest.uuid
index 24ab1f920d..9320755605 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-bf59df66b3613c38cfb13a68091b8328ebb22c78
\ No newline at end of file
+4147f6671e3faa8ddffab8387a6c7d9b5b962fc8
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index 233f674f0f..5d05e98d85 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -5611,7 +5611,6 @@ static int fillInCell(
   BtShared *pBt = pPage->pBt;
   Pgno pgnoOvfl = 0;
   int nHeader;
-  CellInfo info;
 
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
 
@@ -5621,24 +5620,18 @@ static int fillInCell(
             || sqlite3PagerIswriteable(pPage->pDbPage) );
 
   /* Fill in the header. */
-  nHeader = 0;
-  if( !pPage->leaf ){
-    nHeader += 4;
-  }
+  nHeader = pPage->childPtrSize;
+  nPayload = nData + nZero;
   if( pPage->hasData ){
-    nHeader += putVarint32(&pCell[nHeader], nData+nZero);
+    assert( pPage->intKey );
+    nHeader += putVarint32(&pCell[nHeader], nPayload);
   }else{
-    nData = nZero = 0;
+    assert( nData==0 );
+    assert( nZero==0 );
   }
   nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
-  btreeParseCellPtr(pPage, pCell, &info);
-  assert( nHeader=(int)(info.pPayload - pCell) );
-  assert( info.nKey==nKey );
-  assert( pPage->intKey==0 || info.nPayload==(u32)(nData+nZero) );
-  assert( pPage->intKey==1 || info.nPayload==nKey );
   
-  /* Fill in the payload */
-  nPayload = nData + nZero;
+  /* Fill in the payload size */
   if( pPage->intKey ){
     pSrc = pData;
     nSrc = nData;
@@ -5647,15 +5640,55 @@ static int fillInCell(
     if( NEVER(nKey>0x7fffffff || pKey==0) ){
       return SQLITE_CORRUPT_BKPT;
     }
-    nPayload += (int)nKey;
+    nPayload = (int)nKey;
     pSrc = pKey;
     nSrc = (int)nKey;
   }
-  *pnSize = info.nSize;
-  spaceLeft = info.nLocal;
+  if( nPayload<=pPage->maxLocal ){
+    n = nHeader + nPayload;
+    testcase( n==3 );
+    testcase( n==4 );
+    if( n<4 ) n = 4;
+    *pnSize = n;
+    spaceLeft = nPayload;
+    pPrior = pCell;
+  }else{
+    int mn = pPage->minLocal;
+    n = mn + (nPayload - mn) % (pPage->pBt->usableSize - 4);
+    testcase( n==pPage->maxLocal );
+    testcase( n==pPage->maxLocal+1 );
+    if( n > pPage->maxLocal ) n = mn;
+    spaceLeft = n;
+    *pnSize = n + nHeader + 4;
+    pPrior = &pCell[nHeader+n];
+  }
   pPayload = &pCell[nHeader];
-  pPrior = &pCell[info.iOverflow];
 
+  /* At this point variables should be set as follows:
+  **
+  **   nPayload           Total payload size in bytes
+  **   pPayload           Begin writing payload here
+  **   spaceLeft          Space available at pPayload.  If nPayload>spaceLeft,
+  **                      that means content must spill into overflow pages.
+  **   *pnSize            Size of the local cell (not counting overflow pages)
+  **   pPrior             Where to write the pgno of the first overflow page
+  **
+  ** Use a call to btreeParseCellPtr() to verify that the values above
+  ** were computed correctly.
+  */
+#if SQLITE_DEBUG
+  {
+    CellInfo info;
+    btreeParseCellPtr(pPage, pCell, &info);
+    assert( nHeader=(int)(info.pPayload - pCell) );
+    assert( info.nKey==nKey );
+    assert( *pnSize == info.nSize );
+    assert( spaceLeft == info.nLocal );
+    assert( pPrior == &pCell[info.iOverflow] );
+  }
+#endif
+
+  /* Write the payload into the local Cell and any extra into overflow pages */
   while( nPayload>0 ){
     if( spaceLeft==0 ){
 #ifndef SQLITE_OMIT_AUTOVACUUM