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Overview
Comment:Minor performance optimizations to sqlite3_blob_open() and sqlite3_blob_reopen().
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SHA1: 52a61967d920047ea0b4409b79793e05c0128964
User & Date: drh 2017-01-20 00:40:26
Context
2017-01-20
16:09
Get the "--testset rtree" option working on speedtest1. Add the --rtree, --lookaside, and --clang options to the speed-check.sh script. check-in: 87b640c8 user: drh tags: trunk
00:40
Minor performance optimizations to sqlite3_blob_open() and sqlite3_blob_reopen(). check-in: 52a61967 user: drh tags: trunk
2017-01-19
21:20
If compiled with SQLITE_INLINE_MEMCPY, all memcpy() calls are replaced with in-line code. With that change, cachegrind shows which memcpy() calls are taking the most time. This is a performance-measurement hack only and is not for production use. check-in: 9ed38521 user: drh tags: trunk
Changes
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Changes to src/vdbeblob.c.

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** immediately return SQLITE_ABORT.
*/
static int blobSeekToRow(Incrblob *p, sqlite3_int64 iRow, char **pzErr){
  int rc;                         /* Error code */
  char *zErr = 0;                 /* Error message */
  Vdbe *v = (Vdbe *)p->pStmt;

  /* Set the value of the SQL statements only variable to integer iRow. 
  ** This is done directly instead of using sqlite3_bind_int64() to avoid 
  ** triggering asserts related to mutexes.
  */
  assert( v->aVar[0].flags&MEM_Int );

  v->aVar[0].u.i = iRow;







  rc = sqlite3_step(p->pStmt);
  if( rc==SQLITE_ROW ){
    VdbeCursor *pC = v->apCsr[0];
    u32 type = pC->aType[p->iCol];
    if( type<12 ){
      zErr = sqlite3MPrintf(p->db, "cannot open value of type %s",
................................................................................
      ** which closes the b-tree cursor and (possibly) commits the 
      ** transaction.
      */
      static const int iLn = VDBE_OFFSET_LINENO(2);
      static const VdbeOpList openBlob[] = {
        {OP_TableLock,      0, 0, 0},  /* 0: Acquire a read or write lock */
        {OP_OpenRead,       0, 0, 0},  /* 1: Open a cursor */
        {OP_Variable,       1, 1, 0},  /* 2: Move ?1 into reg[1] */
        {OP_NotExists,      0, 7, 1},  /* 3: Seek the cursor */
        {OP_Column,         0, 0, 1},  /* 4  */
        {OP_ResultRow,      1, 0, 0},  /* 5  */
        {OP_Goto,           0, 2, 0},  /* 6  */
        {OP_Halt,           0, 0, 0},  /* 7  */
      };
      Vdbe *v = (Vdbe *)pBlob->pStmt;
      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
      VdbeOp *aOp;

      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, flags, 
                           pTab->pSchema->schema_cookie,
................................................................................
        ** does. An OP_Column to retrieve this imaginary column will
        ** always return an SQL NULL. This is useful because it means
        ** we can invoke OP_Column to fill in the vdbe cursors type 
        ** and offset cache without causing any IO.
        */
        aOp[1].p4type = P4_INT32;
        aOp[1].p4.i = pTab->nCol+1;
        aOp[4].p2 = pTab->nCol;

        pParse->nVar = 1;
        pParse->nMem = 1;
        pParse->nTab = 1;
        sqlite3VdbeMakeReady(v, pParse);
      }
    }
   
    pBlob->flags = flags;







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** immediately return SQLITE_ABORT.
*/
static int blobSeekToRow(Incrblob *p, sqlite3_int64 iRow, char **pzErr){
  int rc;                         /* Error code */
  char *zErr = 0;                 /* Error message */
  Vdbe *v = (Vdbe *)p->pStmt;

  /* Set the value of register r[1] in the SQL statement to integer iRow. 
  ** This is done directly as a performance optimization

  */

  v->aMem[1].flags = MEM_Int;
  v->aMem[1].u.i = iRow;

  /* If the statement has been run before (and is paused at the OP_ResultRow)
  ** then back it up to the point where it does the OP_SeekRowid.  This could
  ** have been down with an extra OP_Goto, but simply setting the program
  ** counter is faster. */
  if( v->pc>3 ) v->pc = 3;

  rc = sqlite3_step(p->pStmt);
  if( rc==SQLITE_ROW ){
    VdbeCursor *pC = v->apCsr[0];
    u32 type = pC->aType[p->iCol];
    if( type<12 ){
      zErr = sqlite3MPrintf(p->db, "cannot open value of type %s",
................................................................................
      ** which closes the b-tree cursor and (possibly) commits the 
      ** transaction.
      */
      static const int iLn = VDBE_OFFSET_LINENO(2);
      static const VdbeOpList openBlob[] = {
        {OP_TableLock,      0, 0, 0},  /* 0: Acquire a read or write lock */
        {OP_OpenRead,       0, 0, 0},  /* 1: Open a cursor */
        /* blobSeekToRow() will initialize r[1] to the desired rowid */
        {OP_NotExists,      0, 5, 1},  /* 2: Seek the cursor to rowid=r[1] */
        {OP_Column,         0, 0, 1},  /* 3  */
        {OP_ResultRow,      1, 0, 0},  /* 4  */

        {OP_Halt,           0, 0, 0},  /* 5  */
      };
      Vdbe *v = (Vdbe *)pBlob->pStmt;
      int iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
      VdbeOp *aOp;

      sqlite3VdbeAddOp4Int(v, OP_Transaction, iDb, flags, 
                           pTab->pSchema->schema_cookie,
................................................................................
        ** does. An OP_Column to retrieve this imaginary column will
        ** always return an SQL NULL. This is useful because it means
        ** we can invoke OP_Column to fill in the vdbe cursors type 
        ** and offset cache without causing any IO.
        */
        aOp[1].p4type = P4_INT32;
        aOp[1].p4.i = pTab->nCol+1;
        aOp[3].p2 = pTab->nCol;

        pParse->nVar = 0;
        pParse->nMem = 1;
        pParse->nTab = 1;
        sqlite3VdbeMakeReady(v, pParse);
      }
    }
   
    pBlob->flags = flags;