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Overview
Comment:Have each open database allocate its pTmpSpace when the first write cursor is opened, rather than on each insert or delete, for a small space savings and performance boost.
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SHA1: 99323552c001bc9173eb2a44542234c8ef7a9845
User & Date: drh 2014-09-24 19:47:27.033
Context
2014-09-25
00:56
Size reduction and performance improvement in the LIKE and GLOB operators. (check-in: b2c89ef49c user: drh tags: trunk)
2014-09-24
19:47
Have each open database allocate its pTmpSpace when the first write cursor is opened, rather than on each insert or delete, for a small space savings and performance boost. (check-in: 99323552c0 user: drh tags: trunk)
18:31
Small performance and size optimization for btreeUnlockIfUnused(). (check-in: 13c746f85d user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c.
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  assert( p->inTrans>TRANS_NONE );
  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1 && pBt->pPage1->aData );

  if( NEVER(wrFlag && (pBt->btsFlags & BTS_READ_ONLY)!=0) ){
    return SQLITE_READONLY;
  }




  if( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
  }

  /* Now that no other errors can occur, finish filling in the BtCursor
  ** variables and link the cursor into the BtShared list.  */








>
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>








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  assert( p->inTrans>TRANS_NONE );
  assert( wrFlag==0 || p->inTrans==TRANS_WRITE );
  assert( pBt->pPage1 && pBt->pPage1->aData );

  if( NEVER(wrFlag && (pBt->btsFlags & BTS_READ_ONLY)!=0) ){
    return SQLITE_READONLY;
  }
  if( wrFlag ){
    allocateTempSpace(pBt);
    if( pBt->pTmpSpace==0 ) return SQLITE_NOMEM;
  }
  if( iTable==1 && btreePagecount(pBt)==0 ){
    assert( wrFlag==0 );
    iTable = 0;
  }

  /* Now that no other errors can occur, finish filling in the BtCursor
  ** variables and link the cursor into the BtShared list.  */
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  assert( pPage->intKey || nKey>=0 );
  assert( pPage->leaf || !pPage->intKey );

  TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
          pCur->pgnoRoot, nKey, nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit );
  allocateTempSpace(pBt);
  newCell = pBt->pTmpSpace;
  if( newCell==0 ) return SQLITE_NOMEM;
  rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
  if( rc ) goto end_insert;
  assert( szNew==cellSizePtr(pPage, newCell) );
  assert( szNew <= MX_CELL_SIZE(pBt) );
  idx = pCur->aiIdx[pCur->iPage];
  if( loc==0 ){
    u16 szOld;








<

|








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  assert( pPage->intKey || nKey>=0 );
  assert( pPage->leaf || !pPage->intKey );

  TRACE(("INSERT: table=%d nkey=%lld ndata=%d page=%d %s\n",
          pCur->pgnoRoot, nKey, nData, pPage->pgno,
          loc==0 ? "overwrite" : "new entry"));
  assert( pPage->isInit );

  newCell = pBt->pTmpSpace;
  assert( newCell!=0 );
  rc = fillInCell(pPage, newCell, pKey, nKey, pData, nData, nZero, &szNew);
  if( rc ) goto end_insert;
  assert( szNew==cellSizePtr(pPage, newCell) );
  assert( szNew <= MX_CELL_SIZE(pBt) );
  idx = pCur->aiIdx[pCur->iPage];
  if( loc==0 ){
    u16 szOld;
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    int nCell;
    Pgno n = pCur->apPage[iCellDepth+1]->pgno;
    unsigned char *pTmp;

    pCell = findCell(pLeaf, pLeaf->nCell-1);
    nCell = cellSizePtr(pLeaf, pCell);
    assert( MX_CELL_SIZE(pBt) >= nCell );

    allocateTempSpace(pBt);
    pTmp = pBt->pTmpSpace;

    rc = sqlite3PagerWrite(pLeaf->pDbPage);
    insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n, &rc);
    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
    if( rc ) return rc;
  }

  /* Balance the tree. If the entry deleted was located on a leaf page,








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    int nCell;
    Pgno n = pCur->apPage[iCellDepth+1]->pgno;
    unsigned char *pTmp;

    pCell = findCell(pLeaf, pLeaf->nCell-1);
    nCell = cellSizePtr(pLeaf, pCell);
    assert( MX_CELL_SIZE(pBt) >= nCell );


    pTmp = pBt->pTmpSpace;
    assert( pTmp!=0 );
    rc = sqlite3PagerWrite(pLeaf->pDbPage);
    insertCell(pPage, iCellIdx, pCell-4, nCell+4, pTmp, n, &rc);
    dropCell(pLeaf, pLeaf->nCell-1, nCell, &rc);
    if( rc ) return rc;
  }

  /* Balance the tree. If the entry deleted was located on a leaf page,
︙︙
Changes to src/vdbe.c.
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  pCur->isOrdered = 1;
  pCur->pgnoRoot = p2;
  rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->pCursor);
  pCur->pKeyInfo = pKeyInfo;
  assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
  sqlite3BtreeCursorHints(pCur->pCursor, (pOp->p5 & OPFLAG_BULKCSR));

  /* Since it performs no memory allocation or IO, the only value that
  ** sqlite3BtreeCursor() may return is SQLITE_OK. */
  assert( rc==SQLITE_OK );

  /* Set the VdbeCursor.isTable variable. Previous versions of
  ** SQLite used to check if the root-page flags were sane at this point
  ** and report database corruption if they were not, but this check has
  ** since moved into the btree layer.  */  
  pCur->isTable = pOp->p4type!=P4_KEYINFO;
  break;
}








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  pCur->isOrdered = 1;
  pCur->pgnoRoot = p2;
  rc = sqlite3BtreeCursor(pX, p2, wrFlag, pKeyInfo, pCur->pCursor);
  pCur->pKeyInfo = pKeyInfo;
  assert( OPFLAG_BULKCSR==BTREE_BULKLOAD );
  sqlite3BtreeCursorHints(pCur->pCursor, (pOp->p5 & OPFLAG_BULKCSR));





  /* Set the VdbeCursor.isTable variable. Previous versions of
  ** SQLite used to check if the root-page flags were sane at this point
  ** and report database corruption if they were not, but this check has
  ** since moved into the btree layer.  */  
  pCur->isTable = pOp->p4type!=P4_KEYINFO;
  break;
}
︙︙