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Overview
Comment:Save CPU cycles in sqlite3Prepare() by, among other things, shifting the EXPLAIN column label logic over to sqlite3VdbeMakeReady().
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SHA3-256: 1ca5ef84506aac3e2f08baa36095b3befdeedf2a3443fcd9154a277b55cbf64b
User & Date: drh 2019-10-09 01:19:07.523
Context
2019-10-09
15:00
Change sqlite3SelectDup() to always return NULL if an OOM has occurred. (check-in: 01ba4641ab user: drh tags: trunk)
13:12
Remove the obsolete "fastfuzztest" target from the makefiles. (check-in: 3d44f1ee0f user: drh tags: makefile-cleanup)
01:19
Save CPU cycles in sqlite3Prepare() by, among other things, shifting the EXPLAIN column label logic over to sqlite3VdbeMakeReady(). (check-in: 1ca5ef8450 user: drh tags: trunk)
2019-10-08
13:34
Fix problems with using the fts5 'rebuild' command inside a transaction that contains other updates of the same table. Fix for [e258f008]. (check-in: 238e083571 user: dan tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/prepare.c.
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      sParse.zTail = &zSql[nBytes];
    }
  }else{
    sqlite3RunParser(&sParse, zSql, &zErrMsg);
  }
  assert( 0==sParse.nQueryLoop );

  if( sParse.rc==SQLITE_DONE ) sParse.rc = SQLITE_OK;


  if( sParse.checkSchema ){
    schemaIsValid(&sParse);
  }
  if( db->mallocFailed ){
    sParse.rc = SQLITE_NOMEM_BKPT;
  }
  if( pzTail ){
    *pzTail = sParse.zTail;
  }
  rc = sParse.rc;

#ifndef SQLITE_OMIT_EXPLAIN
  /* Justification for the ALWAYS(): The only way for rc to be SQLITE_OK and
  ** sParse.pVdbe to be NULL is if the input SQL is an empty string, but in
  ** that case, sParse.explain will be false. */
  if( sParse.explain && rc==SQLITE_OK && ALWAYS(sParse.pVdbe) ){
    static const char * const azColName[] = {
       "addr", "opcode", "p1", "p2", "p3", "p4", "p5", "comment",
       "id", "parent", "notused", "detail"
    };
    int iFirst, mx;
    if( sParse.explain==2 ){
      sqlite3VdbeSetNumCols(sParse.pVdbe, 4);
      iFirst = 8;
      mx = 12;
    }else{
      sqlite3VdbeSetNumCols(sParse.pVdbe, 8);
      iFirst = 0;
      mx = 8;
    }
    for(i=iFirst; i<mx; i++){
      sqlite3VdbeSetColName(sParse.pVdbe, i-iFirst, COLNAME_NAME,

                            azColName[i], SQLITE_STATIC);
    }
  }
#endif

  if( db->init.busy==0 ){
    sqlite3VdbeSetSql(sParse.pVdbe, zSql, (int)(sParse.zTail-zSql), prepFlags);
  }
  if( rc!=SQLITE_OK || db->mallocFailed ){
    if( sParse.pVdbe ) sqlite3VdbeFinalize(sParse.pVdbe);
    assert(!(*ppStmt));
  }else{
    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
  }

  if( zErrMsg ){








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      sParse.zTail = &zSql[nBytes];
    }
  }else{
    sqlite3RunParser(&sParse, zSql, &zErrMsg);
  }
  assert( 0==sParse.nQueryLoop );

  if( sParse.rc==SQLITE_DONE ){
    sParse.rc = SQLITE_OK;
  }
  if( sParse.checkSchema ){
    schemaIsValid(&sParse);
  }



  if( pzTail ){
    *pzTail = sParse.zTail;
  }












  if( db->init.busy==0 ){
    sqlite3VdbeSetSql(sParse.pVdbe, zSql, (int)(sParse.zTail-zSql), prepFlags);






  }


  if( db->mallocFailed ){
    sParse.rc = SQLITE_NOMEM_BKPT;
  }


  rc = sParse.rc;



  if( rc!=SQLITE_OK ){
    if( sParse.pVdbe ) sqlite3VdbeFinalize(sParse.pVdbe);
    assert(!(*ppStmt));
  }else{
    *ppStmt = (sqlite3_stmt*)sParse.pVdbe;
  }

  if( zErrMsg ){
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Changes to src/vdbeaux.c.
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  assert( EIGHT_BYTE_ALIGNMENT(x.pSpace) );
  x.nFree = ROUNDDOWN8(pParse->szOpAlloc - n);  /* Bytes of unused memory */
  assert( x.nFree>=0 );
  assert( EIGHT_BYTE_ALIGNMENT(&x.pSpace[x.nFree]) );

  resolveP2Values(p, &nArg);
  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
  if( pParse->explain && nMem<10 ){





    nMem = 10;













  }
  p->expired = 0;

  /* Memory for registers, parameters, cursor, etc, is allocated in one or two
  ** passes.  On the first pass, we try to reuse unused memory at the 
  ** end of the opcode array.  If we are unable to satisfy all memory
  ** requirements by reusing the opcode array tail, then the second








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  assert( EIGHT_BYTE_ALIGNMENT(x.pSpace) );
  x.nFree = ROUNDDOWN8(pParse->szOpAlloc - n);  /* Bytes of unused memory */
  assert( x.nFree>=0 );
  assert( EIGHT_BYTE_ALIGNMENT(&x.pSpace[x.nFree]) );

  resolveP2Values(p, &nArg);
  p->usesStmtJournal = (u8)(pParse->isMultiWrite && pParse->mayAbort);
  if( pParse->explain ){
    static const char * const azColName[] = {
       "addr", "opcode", "p1", "p2", "p3", "p4", "p5", "comment",
       "id", "parent", "notused", "detail"
    };
    int iFirst, mx, i;
    if( nMem<10 ) nMem = 10;
    if( pParse->explain==2 ){
      sqlite3VdbeSetNumCols(p, 4);
      iFirst = 8;
      mx = 12;
    }else{
      sqlite3VdbeSetNumCols(p, 8);
      iFirst = 0;
      mx = 8;
    }
    for(i=iFirst; i<mx; i++){
      sqlite3VdbeSetColName(p, i-iFirst, COLNAME_NAME,
                            azColName[i], SQLITE_STATIC);
    }
  }
  p->expired = 0;

  /* Memory for registers, parameters, cursor, etc, is allocated in one or two
  ** passes.  On the first pass, we try to reuse unused memory at the 
  ** end of the opcode array.  If we are unable to satisfy all memory
  ** requirements by reusing the opcode array tail, then the second
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