/ Check-in [989573a5]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Do not open a statement journal unless absolutely necessary. (CVS 2499)
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 989573a53b58c1e959ad276119298ba2ea7448e6
User & Date: drh 2005-06-07 01:43:41
Context
2005-06-07
02:12
Add tests to make sure statement journals are only opened when necessary. (CVS 2500) check-in: 914d6e65 user: drh tags: trunk
01:43
Do not open a statement journal unless absolutely necessary. (CVS 2499) check-in: 989573a5 user: drh tags: trunk
2005-06-06
21:19
Reference count Table structures so that they are not deallocated too soon. Ticket #1210. (CVS 2498) check-in: e73d25c7 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/vdbeaux.c.

216
217
218
219
220
221
222






223
224
225
226
227
228
229


230
231
232
233
234
235
236
237
238
239










240
241
242
243
244
245
246
...
248
249
250
251
252
253
254













255
256
257
258
259
260
261
...
685
686
687
688
689
690
691
692


693
694
695
696
697
698
699
**
** Variable *pMaxFuncArgs is set to the maximum value of any P1 argument 
** to an OP_Function or P2 to an OP_AggFunc opcode. This is used by 
** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
**
** The integer *pMaxStack is set to the maximum number of vdbe stack
** entries that static analysis reveals this program might need.






*/
static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs, int *pMaxStack){
  int i;
  int nMaxArgs = 0;
  int nMaxStack = p->nOp;
  Op *pOp;
  int *aLabel = p->aLabel;


  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    /* Todo: Maybe OP_AggFunc should change to use P1 in the same
     * way as OP_Function. 
     */
    if( opcode==OP_Function ){
      if( pOp->p1>nMaxArgs ) nMaxArgs = pOp->p1;
    }else if( opcode==OP_AggFunc ){
      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;










    }

    if( opcodeNoPush(opcode) ){
      nMaxStack--;
    }

    if( pOp->p2>=0 ) continue;
................................................................................
    pOp->p2 = aLabel[-1-pOp->p2];
  }
  sqliteFree(p->aLabel);
  p->aLabel = 0;

  *pMaxFuncArgs = nMaxArgs;
  *pMaxStack = nMaxStack;













}

/*
** Return the address of the next instruction to be inserted.
*/
int sqlite3VdbeCurrentAddr(Vdbe *p){
  assert( p->magic==VDBE_MAGIC_INIT );
................................................................................
   * state.
   */
  p->magic = VDBE_MAGIC_RUN;

  /* No instruction ever pushes more than a single element onto the
  ** stack.  And the stack never grows on successive executions of the
  ** same loop.  So the total number of instructions is an upper bound
  ** on the maximum stack depth required.


  **
  ** Allocation all the stack space we will ever need.
  */
  if( p->aStack==0 ){
    int nArg;       /* Maximum number of args passed to a user function. */
    int nStack;     /* Maximum number of stack entries required */
    resolveP2Values(p, &nArg, &nStack);







>
>
>
>
>
>







>
>










>
>
>
>
>
>
>
>
>
>







 







>
>
>
>
>
>
>
>
>
>
>
>
>







 







|
>
>







216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
...
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
...
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
**
** Variable *pMaxFuncArgs is set to the maximum value of any P1 argument 
** to an OP_Function or P2 to an OP_AggFunc opcode. This is used by 
** sqlite3VdbeMakeReady() to size the Vdbe.apArg[] array.
**
** The integer *pMaxStack is set to the maximum number of vdbe stack
** entries that static analysis reveals this program might need.
**
** This routine also does the following optimization:  It scans for
** Halt instructions where P1==SQLITE_CONSTRAINT or P2==OE_Abort or for
** IdxPut instructions where P2!=0.  If no such instruction is
** found, then every Statement instruction is changed to a Noop.  In
** this way, we avoid creating the statement journal file unnecessarily.
*/
static void resolveP2Values(Vdbe *p, int *pMaxFuncArgs, int *pMaxStack){
  int i;
  int nMaxArgs = 0;
  int nMaxStack = p->nOp;
  Op *pOp;
  int *aLabel = p->aLabel;
  int doesStatementRollback = 0;
  int hasStatementBegin = 0;
  for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
    u8 opcode = pOp->opcode;

    /* Todo: Maybe OP_AggFunc should change to use P1 in the same
     * way as OP_Function. 
     */
    if( opcode==OP_Function ){
      if( pOp->p1>nMaxArgs ) nMaxArgs = pOp->p1;
    }else if( opcode==OP_AggFunc ){
      if( pOp->p2>nMaxArgs ) nMaxArgs = pOp->p2;
    }else if( opcode==OP_Halt ){
      if( pOp->p1==SQLITE_CONSTRAINT && pOp->p2==OE_Abort ){
        doesStatementRollback = 1;
      }
    }else if( opcode==OP_IdxPut ){
      if( pOp->p2 ){
        doesStatementRollback = 1;
      }
    }else if( opcode==OP_Statement ){
      hasStatementBegin = 1;
    }

    if( opcodeNoPush(opcode) ){
      nMaxStack--;
    }

    if( pOp->p2>=0 ) continue;
................................................................................
    pOp->p2 = aLabel[-1-pOp->p2];
  }
  sqliteFree(p->aLabel);
  p->aLabel = 0;

  *pMaxFuncArgs = nMaxArgs;
  *pMaxStack = nMaxStack;

  /* If we never rollback a statement transaction, then statement
  ** transactions are not needed.  So change every OP_Statement
  ** opcode into an OP_Noop.  This avoid a call to sqlite3OsOpenExclusive()
  ** which can be expensive on some platforms.
  */
  if( hasStatementBegin && !doesStatementRollback ){
    for(pOp=p->aOp, i=p->nOp-1; i>=0; i--, pOp++){
      if( pOp->opcode==OP_Statement ){
        pOp->opcode = OP_Noop;
      }
    }
  }
}

/*
** Return the address of the next instruction to be inserted.
*/
int sqlite3VdbeCurrentAddr(Vdbe *p){
  assert( p->magic==VDBE_MAGIC_INIT );
................................................................................
   * state.
   */
  p->magic = VDBE_MAGIC_RUN;

  /* No instruction ever pushes more than a single element onto the
  ** stack.  And the stack never grows on successive executions of the
  ** same loop.  So the total number of instructions is an upper bound
  ** on the maximum stack depth required.  (Added later:)  The
  ** resolveP2Values() call computes a tighter upper bound on the
  ** stack size.
  **
  ** Allocation all the stack space we will ever need.
  */
  if( p->aStack==0 ){
    int nArg;       /* Maximum number of args passed to a user function. */
    int nStack;     /* Maximum number of stack entries required */
    resolveP2Values(p, &nArg, &nStack);