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Overview
Comment:Minor performance optimization and size reduction to the accessPayload() routine in btree.c.
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SHA1: 264e5c10d7144910b3223b64546567fa20e4bc65
User & Date: drh 2017-01-20 20:43:14.971
Context
2017-01-21
14:11
Remove an unnecessary sqlite3_bind_int64() call from sqlite3_blob_open(). Also other minor refactoring of the sqlite3_blob implementation. (check-in: 9d197a5323 user: drh tags: trunk)
2017-01-20
20:43
Minor performance optimization and size reduction to the accessPayload() routine in btree.c. (check-in: 264e5c10d7 user: drh tags: trunk)
16:47
Fix a typo in the help message for kvtest. (check-in: 8971d98f25 user: dan tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c.
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    if( eOp!=2 && (pCur->curFlags & BTCF_ValidOvfl)==0 ){
      int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
      if( nOvfl>pCur->nOvflAlloc ){
        Pgno *aNew = (Pgno*)sqlite3Realloc(
            pCur->aOverflow, nOvfl*2*sizeof(Pgno)
        );
        if( aNew==0 ){
          rc = SQLITE_NOMEM_BKPT;
        }else{
          pCur->nOvflAlloc = nOvfl*2;
          pCur->aOverflow = aNew;
        }
      }
      if( rc==SQLITE_OK ){
        memset(pCur->aOverflow, 0, nOvfl*sizeof(Pgno));
        pCur->curFlags |= BTCF_ValidOvfl;
      }
    }

    /* If the overflow page-list cache has been allocated and the
    ** entry for the first required overflow page is valid, skip
    ** directly to it.
    */
    if( (pCur->curFlags & BTCF_ValidOvfl)!=0
     && pCur->aOverflow[offset/ovflSize]
    ){
      iIdx = (offset/ovflSize);
      nextPage = pCur->aOverflow[iIdx];
      offset = (offset%ovflSize);
    }

    for( ; rc==SQLITE_OK && amt>0 && nextPage; iIdx++){

      /* If required, populate the overflow page-list cache. */
      if( (pCur->curFlags & BTCF_ValidOvfl)!=0 ){
        assert( pCur->aOverflow[iIdx]==0
                || pCur->aOverflow[iIdx]==nextPage
                || CORRUPT_DB );
        pCur->aOverflow[iIdx] = nextPage;
      }








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    if( eOp!=2 && (pCur->curFlags & BTCF_ValidOvfl)==0 ){
      int nOvfl = (pCur->info.nPayload-pCur->info.nLocal+ovflSize-1)/ovflSize;
      if( nOvfl>pCur->nOvflAlloc ){
        Pgno *aNew = (Pgno*)sqlite3Realloc(
            pCur->aOverflow, nOvfl*2*sizeof(Pgno)
        );
        if( aNew==0 ){
          return SQLITE_NOMEM_BKPT;
        }else{
          pCur->nOvflAlloc = nOvfl*2;
          pCur->aOverflow = aNew;
        }
      }

      memset(pCur->aOverflow, 0, nOvfl*sizeof(Pgno));
      pCur->curFlags |= BTCF_ValidOvfl;

    }

    /* If the overflow page-list cache has been allocated and the
    ** entry for the first required overflow page is valid, skip
    ** directly to it.
    */
    if( (pCur->curFlags & BTCF_ValidOvfl)!=0
     && pCur->aOverflow[offset/ovflSize]
    ){
      iIdx = (offset/ovflSize);
      nextPage = pCur->aOverflow[iIdx];
      offset = (offset%ovflSize);
    }

    assert( rc==SQLITE_OK && amt>0 );
    while( nextPage ){
      /* If required, populate the overflow page-list cache. */
      if( (pCur->curFlags & BTCF_ValidOvfl)!=0 ){
        assert( pCur->aOverflow[iIdx]==0
                || pCur->aOverflow[iIdx]==nextPage
                || CORRUPT_DB );
        pCur->aOverflow[iIdx] = nextPage;
      }
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            sqlite3PagerUnref(pDbPage);
            offset = 0;
          }
        }
        amt -= a;
        pBuf += a;
      }



    }
  }

  if( rc==SQLITE_OK && amt>0 ){
    return SQLITE_CORRUPT_BKPT;
  }
  return rc;








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            sqlite3PagerUnref(pDbPage);
            offset = 0;
          }
        }
        amt -= a;
        pBuf += a;
      }
      if( amt==0 ) break;
      if( rc ) break;
      iIdx++;
    }
  }

  if( rc==SQLITE_OK && amt>0 ){
    return SQLITE_CORRUPT_BKPT;
  }
  return rc;
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