SQLite: Check-in [b6b73a74]

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Overview

Comment:	Small performance improvement to OP_Column.
Downloads:	Tarball \| ZIP archive \| SQL archive
Timelines:	family \| ancestors \| descendants \| both \| experimental
Files:	files \| file ages \| folders
SHA1:	b6b73a747ad8d0f026074e41c2a4adc529ec2674
User & Date:	drh 2011-08-29 02:16:18

Context

2011-08-29
02:49		About a 1% overall performance improvement by using a macro to avoid no-op calls to sqlite3MemReleaseExternal(). (Closed-Leaf check-in: ff71d20a user: drh tags: experimental)
02:16		Small performance improvement to OP_Column. (check-in: b6b73a74 user: drh tags: experimental)
2011-08-28
02:15		About a 3% improvement in the performance of OP_Column. (check-in: edff9d4a user: drh tags: experimental)

Changes

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Changes to src/vdbe.c.

  Mem sMem;          /* For storing the record being decoded */
  u8 *zIdx;          /* Index into header */
  u8 *zEndHdr;       /* Pointer to first byte after the header */
  u32 offset;        /* Offset into the data */
  u32 szField;       /* Number of bytes in the content of a field */
  int szHdr;         /* Size of the header size field at start of record */
  int avail;         /* Number of bytes of available data */

  Mem *pReg;         /* PseudoTable input register */


  p1 = pOp->p1;
  p2 = pOp->p2;
  pC = 0;
  memset(&sMem, 0, sizeof(sMem));
................................................................................
    ** arrays.  aType[i] will contain the type integer for the i-th
    ** column and aOffset[i] will contain the offset from the beginning
    ** of the record to the start of the data for the i-th column
    */
    for(i=0; i<nField; i++){
      if( zIdx<zEndHdr ){
        aOffset[i] = offset;




        zIdx += getVarint32(zIdx, aType[i]);


        szField = sqlite3VdbeSerialTypeLen(aType[i]);
        offset += szField;
        if( offset<szField ){  /* True if offset overflows */
          zIdx = &zEndHdr[1];  /* Forces SQLITE_CORRUPT return below */
          break;
        }
      }else{
        /* If i is less that nField, then there are less fields in this








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  Mem sMem;          /* For storing the record being decoded */
  u8 *zIdx;          /* Index into header */
  u8 *zEndHdr;       /* Pointer to first byte after the header */
  u32 offset;        /* Offset into the data */
  u32 szField;       /* Number of bytes in the content of a field */
  int szHdr;         /* Size of the header size field at start of record */
  int avail;         /* Number of bytes of available data */
  u32 t;             /* A type code from the record header */
  Mem *pReg;         /* PseudoTable input register */


  p1 = pOp->p1;
  p2 = pOp->p2;
  pC = 0;
  memset(&sMem, 0, sizeof(sMem));
................................................................................
    ** arrays.  aType[i] will contain the type integer for the i-th
    ** column and aOffset[i] will contain the offset from the beginning
    ** of the record to the start of the data for the i-th column
    */
    for(i=0; i<nField; i++){
      if( zIdx<zEndHdr ){
        aOffset[i] = offset;
        if( zIdx[0]<0x80 ){
          t = zIdx[0];
          zIdx++;
        }else{
          zIdx += sqlite3GetVarint32(zIdx, &t);
        }
        aType[i] = t;
        szField = sqlite3VdbeSerialTypeLen(t);
        offset += szField;
        if( offset<szField ){  /* True if offset overflows */
          zIdx = &zEndHdr[1];  /* Forces SQLITE_CORRUPT return below */
          break;
        }
      }else{
        /* If i is less that nField, then there are less fields in this