From: drh <>
Date: Sat, 25 Feb 2023 16:03:28 +0000 (+0000)
Subject: Split out a new variant of cellSizePtr() that applies only to leaf pages,
X-Git-Tag: version-3.42.0~319
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2d7829057e3806e232f12b66169158fd8f090266;p=thirdparty%2Fsqlite.git

Split out a new variant of cellSizePtr() that applies only to leaf pages,
for a small performance increase.

FossilOrigin-Name: 22d32eef8741ae4f2aac3869465e5a7d2e33c6bc2425dd8e77f2a746e43687e8
---

diff --git a/manifest b/manifest
index 9c0eef5077..ddc9f57b71 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Remove\san\sunnecessary\sand\sredundant\scorruption\schecks\sin\sdefragmentPage().
-D 2023-02-25T15:34:09.046
+C Split\sout\sa\snew\svariant\sof\scellSizePtr()\sthat\sapplies\sonly\sto\sleaf\spages,\nfor\sa\ssmall\sperformance\sincrease.
+D 2023-02-25T16:03:28.921
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -560,7 +560,7 @@ F src/auth.c f4fa91b6a90bbc8e0d0f738aa284551739c9543a367071f55574681e0f24f8cf
 F src/backup.c a2891172438e385fdbe97c11c9745676bec54f518d4447090af97189fd8e52d7
 F src/bitvec.c 7c849aac407230278445cb069bebc5f89bf2ddd87c5ed9459b070a9175707b3d
 F src/btmutex.c 6ffb0a22c19e2f9110be0964d0731d2ef1c67b5f7fabfbaeb7b9dabc4b7740ca
-F src/btree.c ff9634e33c27a77a49d430e32f2aa6a16502632376a6f0b65bcf12e09d7ca4d2
+F src/btree.c 04bf3d1c49c9000af0e2d50f04198641fd7dfc6e4eae495cb60b002d38b45e27
 F src/btree.h aa354b9bad4120af71e214666b35132712b8f2ec11869cb2315c52c81fad45cc
 F src/btreeInt.h 06bb2c1a07172d5a1cd27a2a5d617b93b1e976c5873709c31964786f86365a6e
 F src/build.c c55ab6d1b089ceef57160e840f05f692955ac90944c3d04fcf01d97fd7bfd08d
@@ -2046,8 +2046,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 1c6cfcf6ed5e084e5eb6874a261f3670ab5fb3e5dbcf150f37c58b2f16351ee3
-R 6f0a4ee3eb90075db6e6500bcbce2e80
+P 2dc7342e12e9dac2d8345d045a17caa29c26eaf6f417dd052c7c645eddd6c58c
+R 7550d632ae1e4db50e93659ce002df8e
 U drh
-Z 9c68161318f8714b2adb3b454cee5391
+Z 36cbe33dfaff9cae13269d630b44e5c2
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 5a09b45c8e..32b031f27e 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-2dc7342e12e9dac2d8345d045a17caa29c26eaf6f417dd052c7c645eddd6c58c
\ No newline at end of file
+22d32eef8741ae4f2aac3869465e5a7d2e33c6bc2425dd8e77f2a746e43687e8
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index 2f6ab428b6..8296294dbf 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -1328,10 +1328,11 @@ static void btreeParseCell(
 **
 ** cellSizePtrNoPayload()    =>   table internal nodes
 ** cellSizePtrTableLeaf()    =>   table leaf nodes
-** cellSizePtr()             =>   all index nodes & table leaf nodes
+** cellSizePtr()             =>   index internal nodes
+** cellSizeIdxLeaf()         =>   index leaf nodes
 */
 static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
-  u8 *pIter = pCell + pPage->childPtrSize; /* For looping over bytes of pCell */
+  u8 *pIter = pCell + 4;                   /* For looping over bytes of pCell */
   u8 *pEnd;                                /* End mark for a varint */
   u32 nSize;                               /* Size value to return */
 
@@ -1344,6 +1345,49 @@ static u16 cellSizePtr(MemPage *pPage, u8 *pCell){
   pPage->xParseCell(pPage, pCell, &debuginfo);
 #endif
 
+  assert( pPage->childPtrSize==4 );
+  nSize = *pIter;
+  if( nSize>=0x80 ){
+    pEnd = &pIter[8];
+    nSize &= 0x7f;
+    do{
+      nSize = (nSize<<7) | (*++pIter & 0x7f);
+    }while( *(pIter)>=0x80 && pIter<pEnd );
+  }
+  pIter++;
+  testcase( nSize==pPage->maxLocal );
+  testcase( nSize==(u32)pPage->maxLocal+1 );
+  if( nSize<=pPage->maxLocal ){
+    nSize += (u32)(pIter - pCell);
+    assert( nSize>4 );
+  }else{
+    int minLocal = pPage->minLocal;
+    nSize = minLocal + (nSize - minLocal) % (pPage->pBt->usableSize - 4);
+    testcase( nSize==pPage->maxLocal );
+    testcase( nSize==(u32)pPage->maxLocal+1 );
+    if( nSize>pPage->maxLocal ){
+      nSize = minLocal;
+    }
+    nSize += 4 + (u16)(pIter - pCell);
+  }
+  assert( nSize==debuginfo.nSize || CORRUPT_DB );
+  return (u16)nSize;
+}
+static u16 cellSizePtrIdxLeaf(MemPage *pPage, u8 *pCell){
+  u8 *pIter = pCell;                       /* For looping over bytes of pCell */
+  u8 *pEnd;                                /* End mark for a varint */
+  u32 nSize;                               /* Size value to return */
+
+#ifdef SQLITE_DEBUG
+  /* The value returned by this function should always be the same as
+  ** the (CellInfo.nSize) value found by doing a full parse of the
+  ** cell. If SQLITE_DEBUG is defined, an assert() at the bottom of
+  ** this function verifies that this invariant is not violated. */
+  CellInfo debuginfo;
+  pPage->xParseCell(pPage, pCell, &debuginfo);
+#endif
+
+  assert( pPage->childPtrSize==0 );
   nSize = *pIter;
   if( nSize>=0x80 ){
     pEnd = &pIter[8];
@@ -1925,14 +1969,14 @@ static int decodeFlags(MemPage *pPage, int flagByte){
     }else if( flagByte==(PTF_ZERODATA | PTF_LEAF) ){
       pPage->intKey = 0;
       pPage->intKeyLeaf = 0;
-      pPage->xCellSize = cellSizePtr;
+      pPage->xCellSize = cellSizePtrIdxLeaf;
       pPage->xParseCell = btreeParseCellPtrIndex;
       pPage->maxLocal = pBt->maxLocal;
       pPage->minLocal = pBt->minLocal;
     }else{
       pPage->intKey = 0;
       pPage->intKeyLeaf = 0;
-      pPage->xCellSize = cellSizePtr;
+      pPage->xCellSize = cellSizePtrIdxLeaf;
       pPage->xParseCell = btreeParseCellPtrIndex;
       return SQLITE_CORRUPT_PAGE(pPage);
     }