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Overview
Comment:Performance improvements in btreeParseCell() by inlining the varint decoder.
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SHA1:172a864d14fd9f0e3e97d2a13b22222ae0fedd39
User & Date: drh 2015-06-19 20:31:02
Context
2015-06-20
13:18
Make sure that the likelihood() function does not mess up generation of result-set code when it is used (inappropropriately) in a result-set expression. check-in: 7cdbae62 user: drh tags: trunk
2015-06-19
20:31
Performance improvements in btreeParseCell() by inlining the varint decoder. check-in: 172a864d user: drh tags: trunk
20:08
Fix corner cases involving corrupt varint values in record headers. Closed-Leaf check-in: 3189116b user: drh tags: btree-opt
17:19
Add the MemPage.xParseCell method and provide various implementations (variations on the former btreeParseCellPtr()) depending on the page type. check-in: 41d03d88 user: drh tags: trunk
Changes
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Changes to src/btree.c.

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static void btreeParseCellPtr(
  MemPage *pPage,         /* Page containing the cell */
  u8 *pCell,              /* Pointer to the cell text. */
  CellInfo *pInfo         /* Fill in this structure */
){
  u8 *pIter;              /* For scanning through pCell */
  u32 nPayload;           /* Number of bytes of cell payload */


  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( pPage->leaf==0 || pPage->leaf==1 );
  assert( pPage->intKeyLeaf || pPage->noPayload );
  assert( pPage->noPayload==0 );
  assert( pPage->intKeyLeaf );
  assert( pPage->childPtrSize==0 );
  pIter = pCell + getVarint32(pCell, nPayload);



















  pIter += getVarint(pIter, (u64*)&pInfo->nKey);



















  pInfo->nPayload = nPayload;
  pInfo->pPayload = pIter;
  testcase( nPayload==pPage->maxLocal );
  testcase( nPayload==pPage->maxLocal+1 );
  if( nPayload<=pPage->maxLocal ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
................................................................................
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( pPage->leaf==0 || pPage->leaf==1 );
  assert( pPage->intKeyLeaf==0 );
  assert( pPage->noPayload==0 );
  pIter = pCell + pPage->childPtrSize;
  nPayload = *pIter;
  if( nPayload>=0x80 ){
    u8 *pEnd = &pIter[9];
    nPayload &= 0x7f;
    do{
      nPayload = (nPayload<<7) | (*++pIter & 0x7f);
    }while( *(pIter)>=0x80 && pIter<pEnd );
  }
  pIter++;
  pInfo->nKey = nPayload;
................................................................................
  CellInfo debuginfo;
  pPage->xParseCell(pPage, pCell, &debuginfo);
#endif

  assert( pPage->noPayload==0 );
  nSize = *pIter;
  if( nSize>=0x80 ){
    pEnd = &pIter[9];
    nSize &= 0x7f;
    do{
      nSize = (nSize<<7) | (*++pIter & 0x7f);
    }while( *(pIter)>=0x80 && pIter<pEnd );
  }
  pIter++;
  if( pPage->intKey ){







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static void btreeParseCellPtr(
  MemPage *pPage,         /* Page containing the cell */
  u8 *pCell,              /* Pointer to the cell text. */
  CellInfo *pInfo         /* Fill in this structure */
){
  u8 *pIter;              /* For scanning through pCell */
  u32 nPayload;           /* Number of bytes of cell payload */
  u64 iKey;               /* Extracted Key value */

  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( pPage->leaf==0 || pPage->leaf==1 );
  assert( pPage->intKeyLeaf || pPage->noPayload );
  assert( pPage->noPayload==0 );
  assert( pPage->intKeyLeaf );
  assert( pPage->childPtrSize==0 );
  pIter = pCell;

  /* The next block of code is equivalent to:
  **
  **     pIter += getVarint32(pIter, nPayload);
  **
  ** The code is inlined to avoid a function call.
  */
  nPayload = *pIter;
  if( nPayload>=0x80 ){
    u8 *pEnd = &pIter[8];
    nPayload &= 0x7f;
    do{
      nPayload = (nPayload<<7) | (*++pIter & 0x7f);
    }while( (*pIter)>=0x80 && pIter<pEnd );
  }
  pIter++;

  /* The next block of code is equivalent to:
  **
  **     pIter += getVarint(pIter, (u64*)&pInfo->nKey);
  **
  ** The code is inlined to avoid a function call.
  */
  iKey = *pIter;
  if( iKey>=0x80 ){
    u8 *pEnd = &pIter[7];
    iKey &= 0x7f;
    while(1){
      iKey = (iKey<<7) | (*++pIter & 0x7f);
      if( (*pIter)<0x80 ) break;
      if( pIter>=pEnd ){
        iKey = (iKey<<8) | *++pIter;
        break;
      }
    }
  }
  pIter++;

  pInfo->nKey = *(i64*)&iKey;
  pInfo->nPayload = nPayload;
  pInfo->pPayload = pIter;
  testcase( nPayload==pPage->maxLocal );
  testcase( nPayload==pPage->maxLocal+1 );
  if( nPayload<=pPage->maxLocal ){
    /* This is the (easy) common case where the entire payload fits
    ** on the local page.  No overflow is required.
................................................................................
  assert( sqlite3_mutex_held(pPage->pBt->mutex) );
  assert( pPage->leaf==0 || pPage->leaf==1 );
  assert( pPage->intKeyLeaf==0 );
  assert( pPage->noPayload==0 );
  pIter = pCell + pPage->childPtrSize;
  nPayload = *pIter;
  if( nPayload>=0x80 ){
    u8 *pEnd = &pIter[8];
    nPayload &= 0x7f;
    do{
      nPayload = (nPayload<<7) | (*++pIter & 0x7f);
    }while( *(pIter)>=0x80 && pIter<pEnd );
  }
  pIter++;
  pInfo->nKey = nPayload;
................................................................................
  CellInfo debuginfo;
  pPage->xParseCell(pPage, pCell, &debuginfo);
#endif

  assert( pPage->noPayload==0 );
  nSize = *pIter;
  if( nSize>=0x80 ){
    pEnd = &pIter[8];
    nSize &= 0x7f;
    do{
      nSize = (nSize<<7) | (*++pIter & 0x7f);
    }while( *(pIter)>=0x80 && pIter<pEnd );
  }
  pIter++;
  if( pPage->intKey ){

Changes to test/corruptI.test.

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  PRAGMA auto_vacuum=0;
  CREATE TABLE t1(x);
  INSERT INTO t1 VALUES(zeroblob(300));
  INSERT INTO t1 VALUES(zeroblob(600));
} {}
do_test 6.1 {
  db close
  hexio_write test.db 616 EAFFFFFF0202
  sqlite3 db test.db
  breakpoint
  execsql { DELETE FROM t1 WHERE rowid=2 }
} {}

#-------------------------------------------------------------------------
# See what happens if the sqlite_master entry associated with a PRIMARY







|







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  PRAGMA auto_vacuum=0;
  CREATE TABLE t1(x);
  INSERT INTO t1 VALUES(zeroblob(300));
  INSERT INTO t1 VALUES(zeroblob(600));
} {}
do_test 6.1 {
  db close
  hexio_write test.db 616 8FFFFFFF7F02
  sqlite3 db test.db
  breakpoint
  execsql { DELETE FROM t1 WHERE rowid=2 }
} {}

#-------------------------------------------------------------------------
# See what happens if the sqlite_master entry associated with a PRIMARY