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Overview
Comment:Remove an unnecessary sqlite3_bind_int64() call from sqlite3_blob_open(). Also other minor refactoring of the sqlite3_blob implementation.
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SHA1: 9d197a532349f4b1caf66bbed70ca46df86cb86f
User & Date: drh 2017-01-21 14:11:28.343
Context
2017-01-21
15:55
In the kvtest.c test utility, reuse the buffer into which blobs are read, rather than reallocating it for each row. This is a closer match to how other test programs work, and thus provides a better comparison. (check-in: 0d1ad13a29 user: drh tags: trunk)
15:30
A proof-of-concept for running sqlite3_blob_open() without using OP_Column when operating on a pure key/value table. This demo does not include any corrupt database checking. Uses about 3% fewer CPU cycles on a key/value performance test. (Leaf check-in: 4cda3b305b user: drh tags: kv-access-opt-demo)
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)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/vdbeblob.c.
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#ifndef SQLITE_OMIT_INCRBLOB

/*
** Valid sqlite3_blob* handles point to Incrblob structures.
*/
typedef struct Incrblob Incrblob;
struct Incrblob {
  int flags;              /* Copy of "flags" passed to sqlite3_blob_open() */
  int nByte;              /* Size of open blob, in bytes */
  int iOffset;            /* Byte offset of blob in cursor data */
  int iCol;               /* Table column this handle is open on */

  BtCursor *pCsr;         /* Cursor pointing at blob row */
  sqlite3_stmt *pStmt;    /* Statement holding cursor open */
  sqlite3 *db;            /* The associated database */
  char *zDb;              /* Database name */
  Table *pTab;            /* Table object */
};








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#ifndef SQLITE_OMIT_INCRBLOB

/*
** Valid sqlite3_blob* handles point to Incrblob structures.
*/
typedef struct Incrblob Incrblob;
struct Incrblob {

  int nByte;              /* Size of open blob, in bytes */
  int iOffset;            /* Byte offset of blob in cursor data */
  u16 iCol;               /* Table column this handle is open on */
  u8 isPureKV;            /* True if pTab is a pure key/value table */
  BtCursor *pCsr;         /* Cursor pointing at blob row */
  sqlite3_stmt *pStmt;    /* Statement holding cursor open */
  sqlite3 *db;            /* The associated database */
  char *zDb;              /* Database name */
  Table *pTab;            /* Table object */
};

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*/
int sqlite3_blob_open(
  sqlite3* db,            /* The database connection */
  const char *zDb,        /* The attached database containing the blob */
  const char *zTable,     /* The table containing the blob */
  const char *zColumn,    /* The column containing the blob */
  sqlite_int64 iRow,      /* The row containing the glob */
  int flags,              /* True -> read/write access, false -> read-only */
  sqlite3_blob **ppBlob   /* Handle for accessing the blob returned here */
){
  int nAttempt = 0;
  int iCol;               /* Index of zColumn in row-record */
  int rc = SQLITE_OK;
  char *zErr = 0;
  Table *pTab;







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*/
int sqlite3_blob_open(
  sqlite3* db,            /* The database connection */
  const char *zDb,        /* The attached database containing the blob */
  const char *zTable,     /* The table containing the blob */
  const char *zColumn,    /* The column containing the blob */
  sqlite_int64 iRow,      /* The row containing the glob */
  int wrFlag,             /* True -> read/write access, false -> read-only */
  sqlite3_blob **ppBlob   /* Handle for accessing the blob returned here */
){
  int nAttempt = 0;
  int iCol;               /* Index of zColumn in row-record */
  int rc = SQLITE_OK;
  char *zErr = 0;
  Table *pTab;
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#endif
  *ppBlob = 0;
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zTable==0 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  flags = !!flags;                /* flags = (flags ? 1 : 0); */

  sqlite3_mutex_enter(db->mutex);

  pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
  if( !pBlob ) goto blob_open_out;
  pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
  if( !pParse ) goto blob_open_out;







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#endif
  *ppBlob = 0;
#ifdef SQLITE_ENABLE_API_ARMOR
  if( !sqlite3SafetyCheckOk(db) || zTable==0 ){
    return SQLITE_MISUSE_BKPT;
  }
#endif
  wrFlag = !!wrFlag;                /* wrFlag = (wrFlag ? 1 : 0); */

  sqlite3_mutex_enter(db->mutex);

  pBlob = (Incrblob *)sqlite3DbMallocZero(db, sizeof(Incrblob));
  if( !pBlob ) goto blob_open_out;
  pParse = sqlite3StackAllocRaw(db, sizeof(*pParse));
  if( !pParse ) goto blob_open_out;
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      rc = SQLITE_ERROR;
      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }

    /* If the value is being opened for writing, check that the
    ** column is not indexed, and that it is not part of a foreign key. 
    ** It is against the rules to open a column to which either of these
    ** descriptions applies for writing.  */
    if( flags ){
      const char *zFault = 0;
      Index *pIdx;
#ifndef SQLITE_OMIT_FOREIGN_KEY
      if( db->flags&SQLITE_ForeignKeys ){
        /* Check that the column is not part of an FK child key definition. It
        ** is not necessary to check if it is part of a parent key, as parent
        ** key columns must be indexed. The check below will pick up this 







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      rc = SQLITE_ERROR;
      sqlite3BtreeLeaveAll(db);
      goto blob_open_out;
    }

    /* If the value is being opened for writing, check that the
    ** column is not indexed, and that it is not part of a foreign key. 
    */

    if( wrFlag ){
      const char *zFault = 0;
      Index *pIdx;
#ifndef SQLITE_OMIT_FOREIGN_KEY
      if( db->flags&SQLITE_ForeignKeys ){
        /* Check that the column is not part of an FK child key definition. It
        ** is not necessary to check if it is part of a parent key, as parent
        ** key columns must be indexed. The check below will pick up this 
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        {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,
                           pTab->pSchema->iGeneration);
      sqlite3VdbeChangeP5(v, 1);     
      aOp = sqlite3VdbeAddOpList(v, ArraySize(openBlob), openBlob, iLn);

      /* Make sure a mutex is held on the table to be accessed */
      sqlite3VdbeUsesBtree(v, iDb); 

      if( db->mallocFailed==0 ){
        assert( aOp!=0 );
        /* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
        aOp[0].opcode = OP_Noop;
#else
        aOp[0].p1 = iDb;
        aOp[0].p2 = pTab->tnum;
        aOp[0].p3 = flags;
        sqlite3VdbeChangeP4(v, 1, pTab->zName, P4_TRANSIENT);
      }
      if( db->mallocFailed==0 ){
#endif

        /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
        ** parameter of the other to pTab->tnum.  */
        if( flags ) aOp[1].opcode = OP_OpenWrite;
        aOp[1].p2 = pTab->tnum;
        aOp[1].p3 = iDb;   

        /* Configure the number of columns. Configure the cursor to
        ** think that the table has one more column than it really
        ** does. An OP_Column to retrieve this imaginary column will
        ** always return an SQL NULL. This is useful because it means







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        {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, wrFlag, 
                           pTab->pSchema->schema_cookie,
                           pTab->pSchema->iGeneration);
      sqlite3VdbeChangeP5(v, 1);     
      aOp = sqlite3VdbeAddOpList(v, ArraySize(openBlob), openBlob, iLn);

      /* Make sure a mutex is held on the table to be accessed */
      sqlite3VdbeUsesBtree(v, iDb); 

      if( db->mallocFailed==0 ){
        assert( aOp!=0 );
        /* Configure the OP_TableLock instruction */
#ifdef SQLITE_OMIT_SHARED_CACHE
        aOp[0].opcode = OP_Noop;
#else
        aOp[0].p1 = iDb;
        aOp[0].p2 = pTab->tnum;
        aOp[0].p3 = wrFlag;
        sqlite3VdbeChangeP4(v, 1, pTab->zName, P4_TRANSIENT);
      }
      if( db->mallocFailed==0 ){
#endif

        /* Remove either the OP_OpenWrite or OpenRead. Set the P2 
        ** parameter of the other to pTab->tnum.  */
        if( wrFlag ) aOp[1].opcode = OP_OpenWrite;
        aOp[1].p2 = pTab->tnum;
        aOp[1].p3 = iDb;   

        /* Configure the number of columns. Configure the cursor to
        ** think that the table has one more column than it really
        ** does. An OP_Column to retrieve this imaginary column will
        ** always return an SQL NULL. This is useful because it means
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        pParse->nVar = 0;
        pParse->nMem = 1;
        pParse->nTab = 1;
        sqlite3VdbeMakeReady(v, pParse);
      }
    }
   
    pBlob->flags = flags;
    pBlob->iCol = iCol;
    pBlob->db = db;
    sqlite3BtreeLeaveAll(db);
    if( db->mallocFailed ){
      goto blob_open_out;
    }
    sqlite3_bind_int64(pBlob->pStmt, 1, iRow);
    rc = blobSeekToRow(pBlob, iRow, &zErr);
  } while( (++nAttempt)<SQLITE_MAX_SCHEMA_RETRY && rc==SQLITE_SCHEMA );

blob_open_out:
  if( rc==SQLITE_OK && db->mallocFailed==0 ){
    *ppBlob = (sqlite3_blob *)pBlob;
  }else{







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        pParse->nVar = 0;
        pParse->nMem = 1;
        pParse->nTab = 1;
        sqlite3VdbeMakeReady(v, pParse);
      }
    }
   
    pBlob->isPureKV = (pTab->nCol==2 && pTab->iPKey==0);
    pBlob->iCol = iCol;
    pBlob->db = db;
    sqlite3BtreeLeaveAll(db);
    if( db->mallocFailed ){
      goto blob_open_out;
    }

    rc = blobSeekToRow(pBlob, iRow, &zErr);
  } while( (++nAttempt)<SQLITE_MAX_SCHEMA_RETRY && rc==SQLITE_SCHEMA );

blob_open_out:
  if( rc==SQLITE_OK && db->mallocFailed==0 ){
    *ppBlob = (sqlite3_blob *)pBlob;
  }else{