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Overview
Comment:Simplifications to the way UnpackedRecord objects are allocated. Smaller and faster code that also fixes a subtle (currently unreachable) bug.
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Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: f7ab01f254cd9d7006b8dec29adb234a671b8e6f
User & Date: drh 2016-12-21 19:45:54.698
Context
2016-12-21
21:26
Change the default lookaside configuration from 500 slots of 128 bytes each to 125 slots of 512 bytes each. This uses the same amount of memory (64,000 bytes) but seems to perform much better in test applications. (check-in: 52a12e47de user: drh tags: trunk)
19:45
Simplifications to the way UnpackedRecord objects are allocated. Smaller and faster code that also fixes a subtle (currently unreachable) bug. (check-in: f7ab01f254 user: drh tags: trunk)
2016-12-18
17:42
Change the OP_IfNotZero opcode so that it decrements register P1 by 1 rather than the value in P3, and so that it only decrements if originally positive. This avoids decrementing the smallest 64-bit signed integer. (check-in: 165c044686 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/btree.c.
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  const void *pKey,   /* Packed key if the btree is an index */
  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
  int bias,           /* Bias search to the high end */
  int *pRes           /* Write search results here */
){
  int rc;                    /* Status code */
  UnpackedRecord *pIdxKey;   /* Unpacked index key */
  char aSpace[384];          /* Temp space for pIdxKey - to avoid a malloc */
  char *pFree = 0;

  if( pKey ){
    assert( nKey==(i64)(int)nKey );
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(
        pCur->pKeyInfo, aSpace, sizeof(aSpace), &pFree
    );
    if( pIdxKey==0 ) return SQLITE_NOMEM_BKPT;
    sqlite3VdbeRecordUnpack(pCur->pKeyInfo, (int)nKey, pKey, pIdxKey);
    if( pIdxKey->nField==0 ){
      sqlite3DbFree(pCur->pKeyInfo->db, pFree);
      return SQLITE_CORRUPT_BKPT;

    }
  }else{
    pIdxKey = 0;
  }
  rc = sqlite3BtreeMovetoUnpacked(pCur, pIdxKey, nKey, bias, pRes);

  if( pFree ){
    sqlite3DbFree(pCur->pKeyInfo->db, pFree);
  }
  return rc;
}

/*
** Restore the cursor to the position it was in (or as close to as possible)
** when saveCursorPosition() was called. Note that this call deletes the 







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  const void *pKey,   /* Packed key if the btree is an index */
  i64 nKey,           /* Integer key for tables.  Size of pKey for indices */
  int bias,           /* Bias search to the high end */
  int *pRes           /* Write search results here */
){
  int rc;                    /* Status code */
  UnpackedRecord *pIdxKey;   /* Unpacked index key */



  if( pKey ){
    assert( nKey==(i64)(int)nKey );
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(pCur->pKeyInfo);


    if( pIdxKey==0 ) return SQLITE_NOMEM_BKPT;
    sqlite3VdbeRecordUnpack(pCur->pKeyInfo, (int)nKey, pKey, pIdxKey);
    if( pIdxKey->nField==0 ){

      rc = SQLITE_CORRUPT_BKPT;
      goto moveto_done;
    }
  }else{
    pIdxKey = 0;
  }
  rc = sqlite3BtreeMovetoUnpacked(pCur, pIdxKey, nKey, bias, pRes);
moveto_done:
  if( pIdxKey ){
    sqlite3DbFree(pCur->pKeyInfo->db, pIdxKey);
  }
  return rc;
}

/*
** Restore the cursor to the position it was in (or as close to as possible)
** when saveCursorPosition() was called. Note that this call deletes the 
Changes to src/vdbe.c.
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case OP_NotFound:       /* jump, in3 */
case OP_Found: {        /* jump, in3 */
  int alreadyExists;
  int takeJump;
  int ii;
  VdbeCursor *pC;
  int res;
  char *pFree;
  UnpackedRecord *pIdxKey;
  UnpackedRecord r;
  char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*4 + 7];

#ifdef SQLITE_TEST
  if( pOp->opcode!=OP_NoConflict ) sqlite3_found_count++;
#endif

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p4type==P4_INT32 );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
#ifdef SQLITE_DEBUG
  pC->seekOp = pOp->opcode;
#endif
  pIn3 = &aMem[pOp->p3];
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->uc.pCursor!=0 );
  assert( pC->isTable==0 );
  pFree = 0;
  if( pOp->p4.i>0 ){
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = (u16)pOp->p4.i;
    r.aMem = pIn3;
#ifdef SQLITE_DEBUG
    for(ii=0; ii<r.nField; ii++){
      assert( memIsValid(&r.aMem[ii]) );
      assert( (r.aMem[ii].flags & MEM_Zero)==0 || r.aMem[ii].n==0 );
      if( ii ) REGISTER_TRACE(pOp->p3+ii, &r.aMem[ii]);
    }
#endif
    pIdxKey = &r;

  }else{
    pIdxKey = sqlite3VdbeAllocUnpackedRecord(
        pC->pKeyInfo, aTempRec, sizeof(aTempRec), &pFree
    );
    if( pIdxKey==0 ) goto no_mem;
    assert( pIn3->flags & MEM_Blob );
    (void)ExpandBlob(pIn3);
    sqlite3VdbeRecordUnpack(pC->pKeyInfo, pIn3->n, pIn3->z, pIdxKey);
  }
  pIdxKey->default_rc = 0;
  takeJump = 0;
  if( pOp->opcode==OP_NoConflict ){
    /* For the OP_NoConflict opcode, take the jump if any of the
    ** input fields are NULL, since any key with a NULL will not
    ** conflict */
    for(ii=0; ii<pIdxKey->nField; ii++){
      if( pIdxKey->aMem[ii].flags & MEM_Null ){
        takeJump = 1;
        break;
      }
    }
  }
  rc = sqlite3BtreeMovetoUnpacked(pC->uc.pCursor, pIdxKey, 0, 0, &res);
  sqlite3DbFree(db, pFree);
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  pC->seekResult = res;
  alreadyExists = (res==0);
  pC->nullRow = 1-alreadyExists;
  pC->deferredMoveto = 0;







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case OP_NotFound:       /* jump, in3 */
case OP_Found: {        /* jump, in3 */
  int alreadyExists;
  int takeJump;
  int ii;
  VdbeCursor *pC;
  int res;
  UnpackedRecord *pFree;
  UnpackedRecord *pIdxKey;
  UnpackedRecord r;


#ifdef SQLITE_TEST
  if( pOp->opcode!=OP_NoConflict ) sqlite3_found_count++;
#endif

  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
  assert( pOp->p4type==P4_INT32 );
  pC = p->apCsr[pOp->p1];
  assert( pC!=0 );
#ifdef SQLITE_DEBUG
  pC->seekOp = pOp->opcode;
#endif
  pIn3 = &aMem[pOp->p3];
  assert( pC->eCurType==CURTYPE_BTREE );
  assert( pC->uc.pCursor!=0 );
  assert( pC->isTable==0 );

  if( pOp->p4.i>0 ){
    r.pKeyInfo = pC->pKeyInfo;
    r.nField = (u16)pOp->p4.i;
    r.aMem = pIn3;
#ifdef SQLITE_DEBUG
    for(ii=0; ii<r.nField; ii++){
      assert( memIsValid(&r.aMem[ii]) );
      assert( (r.aMem[ii].flags & MEM_Zero)==0 || r.aMem[ii].n==0 );
      if( ii ) REGISTER_TRACE(pOp->p3+ii, &r.aMem[ii]);
    }
#endif
    pIdxKey = &r;
    pFree = 0;
  }else{
    pFree = pIdxKey = sqlite3VdbeAllocUnpackedRecord(pC->pKeyInfo);


    if( pIdxKey==0 ) goto no_mem;
    assert( pIn3->flags & MEM_Blob );
    (void)ExpandBlob(pIn3);
    sqlite3VdbeRecordUnpack(pC->pKeyInfo, pIn3->n, pIn3->z, pIdxKey);
  }
  pIdxKey->default_rc = 0;
  takeJump = 0;
  if( pOp->opcode==OP_NoConflict ){
    /* For the OP_NoConflict opcode, take the jump if any of the
    ** input fields are NULL, since any key with a NULL will not
    ** conflict */
    for(ii=0; ii<pIdxKey->nField; ii++){
      if( pIdxKey->aMem[ii].flags & MEM_Null ){
        takeJump = 1;
        break;
      }
    }
  }
  rc = sqlite3BtreeMovetoUnpacked(pC->uc.pCursor, pIdxKey, 0, 0, &res);
  if( pFree ) sqlite3DbFree(db, pFree);
  if( rc!=SQLITE_OK ){
    goto abort_due_to_error;
  }
  pC->seekResult = res;
  alreadyExists = (res==0);
  pC->nullRow = 1-alreadyExists;
  pC->deferredMoveto = 0;
Changes to src/vdbe.h.
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  char *sqlite3VdbeExpandSql(Vdbe*, const char*);
#endif
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);

void sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,UnpackedRecord*);
int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);
int sqlite3VdbeRecordCompareWithSkip(int, const void *, UnpackedRecord *, int);
UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(KeyInfo *, char *, int, char **);

typedef int (*RecordCompare)(int,const void*,UnpackedRecord*);
RecordCompare sqlite3VdbeFindCompare(UnpackedRecord*);

#ifndef SQLITE_OMIT_TRIGGER
void sqlite3VdbeLinkSubProgram(Vdbe *, SubProgram *);
#endif







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  char *sqlite3VdbeExpandSql(Vdbe*, const char*);
#endif
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);

void sqlite3VdbeRecordUnpack(KeyInfo*,int,const void*,UnpackedRecord*);
int sqlite3VdbeRecordCompare(int,const void*,UnpackedRecord*);
int sqlite3VdbeRecordCompareWithSkip(int, const void *, UnpackedRecord *, int);
UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(KeyInfo*);

typedef int (*RecordCompare)(int,const void*,UnpackedRecord*);
RecordCompare sqlite3VdbeFindCompare(UnpackedRecord*);

#ifndef SQLITE_OMIT_TRIGGER
void sqlite3VdbeLinkSubProgram(Vdbe *, SubProgram *);
#endif
Changes to src/vdbeapi.c.
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** if successful, or a NULL pointer if an OOM error is encountered.
*/
static UnpackedRecord *vdbeUnpackRecord(
  KeyInfo *pKeyInfo, 
  int nKey, 
  const void *pKey
){
  char *dummy;                    /* Dummy argument for AllocUnpackedRecord() */
  UnpackedRecord *pRet;           /* Return value */

  pRet = sqlite3VdbeAllocUnpackedRecord(pKeyInfo, 0, 0, &dummy);
  if( pRet ){
    memset(pRet->aMem, 0, sizeof(Mem)*(pKeyInfo->nField+1));
    sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, pRet);
  }
  return pRet;
}








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** if successful, or a NULL pointer if an OOM error is encountered.
*/
static UnpackedRecord *vdbeUnpackRecord(
  KeyInfo *pKeyInfo, 
  int nKey, 
  const void *pKey
){

  UnpackedRecord *pRet;           /* Return value */

  pRet = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);
  if( pRet ){
    memset(pRet->aMem, 0, sizeof(Mem)*(pKeyInfo->nField+1));
    sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, pRet);
  }
  return pRet;
}

Changes to src/vdbeaux.c.
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** be eventually freed by the caller using sqlite3DbFree(). Or, if the 
** allocation comes from the pSpace/szSpace buffer, *ppFree is set to NULL
** before returning.
**
** If an OOM error occurs, NULL is returned.
*/
UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(
  KeyInfo *pKeyInfo,              /* Description of the record */
  char *pSpace,                   /* Unaligned space available */
  int szSpace,                    /* Size of pSpace[] in bytes */
  char **ppFree                   /* OUT: Caller should free this pointer */
){
  UnpackedRecord *p;              /* Unpacked record to return */
  int nOff;                       /* Increment pSpace by nOff to align it */
  int nByte;                      /* Number of bytes required for *p */

  /* We want to shift the pointer pSpace up such that it is 8-byte aligned.
  ** Thus, we need to calculate a value, nOff, between 0 and 7, to shift 
  ** it by.  If pSpace is already 8-byte aligned, nOff should be zero.
  */
  nOff = (8 - (SQLITE_PTR_TO_INT(pSpace) & 7)) & 7;
  nByte = ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nField+1);
  if( nByte>szSpace+nOff ){
    p = (UnpackedRecord *)sqlite3DbMallocRaw(pKeyInfo->db, nByte);
    *ppFree = (char *)p;
    if( !p ) return 0;
  }else{
    p = (UnpackedRecord*)&pSpace[nOff];
    *ppFree = 0;
  }

  p->aMem = (Mem*)&((char*)p)[ROUND8(sizeof(UnpackedRecord))];
  assert( pKeyInfo->aSortOrder!=0 );
  p->pKeyInfo = pKeyInfo;
  p->nField = pKeyInfo->nField + 1;
  return p;
}








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** be eventually freed by the caller using sqlite3DbFree(). Or, if the 
** allocation comes from the pSpace/szSpace buffer, *ppFree is set to NULL
** before returning.
**
** If an OOM error occurs, NULL is returned.
*/
UnpackedRecord *sqlite3VdbeAllocUnpackedRecord(
  KeyInfo *pKeyInfo               /* Description of the record */



){
  UnpackedRecord *p;              /* Unpacked record to return */

  int nByte;                      /* Number of bytes required for *p */






  nByte = ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*(pKeyInfo->nField+1);

  p = (UnpackedRecord *)sqlite3DbMallocRaw(pKeyInfo->db, nByte);

  if( !p ) return 0;





  p->aMem = (Mem*)&((char*)p)[ROUND8(sizeof(UnpackedRecord))];
  assert( pKeyInfo->aSortOrder!=0 );
  p->pKeyInfo = pKeyInfo;
  p->nField = pKeyInfo->nField + 1;
  return p;
}

Changes to src/vdbesort.c.
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/*
** If it has not already been allocated, allocate the UnpackedRecord 
** structure at pTask->pUnpacked. Return SQLITE_OK if successful (or 
** if no allocation was required), or SQLITE_NOMEM otherwise.
*/
static int vdbeSortAllocUnpacked(SortSubtask *pTask){
  if( pTask->pUnpacked==0 ){
    char *pFree;
    pTask->pUnpacked = sqlite3VdbeAllocUnpackedRecord(
        pTask->pSorter->pKeyInfo, 0, 0, &pFree
    );
    assert( pTask->pUnpacked==(UnpackedRecord*)pFree );
    if( pFree==0 ) return SQLITE_NOMEM_BKPT;
    pTask->pUnpacked->nField = pTask->pSorter->pKeyInfo->nField;
    pTask->pUnpacked->errCode = 0;
  }
  return SQLITE_OK;
}









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/*
** If it has not already been allocated, allocate the UnpackedRecord 
** structure at pTask->pUnpacked. Return SQLITE_OK if successful (or 
** if no allocation was required), or SQLITE_NOMEM otherwise.
*/
static int vdbeSortAllocUnpacked(SortSubtask *pTask){
  if( pTask->pUnpacked==0 ){

    pTask->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pTask->pSorter->pKeyInfo);



    if( pTask->pUnpacked==0 ) return SQLITE_NOMEM_BKPT;
    pTask->pUnpacked->nField = pTask->pSorter->pKeyInfo->nField;
    pTask->pUnpacked->errCode = 0;
  }
  return SQLITE_OK;
}


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  void *pKey; int nKey;           /* Sorter key to compare pVal with */

  assert( pCsr->eCurType==CURTYPE_SORTER );
  pSorter = pCsr->uc.pSorter;
  r2 = pSorter->pUnpacked;
  pKeyInfo = pCsr->pKeyInfo;
  if( r2==0 ){
    char *p;
    r2 = pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pKeyInfo,0,0,&p);
    assert( pSorter->pUnpacked==(UnpackedRecord*)p );
    if( r2==0 ) return SQLITE_NOMEM_BKPT;
    r2->nField = nKeyCol;
  }
  assert( r2->nField==nKeyCol );

  pKey = vdbeSorterRowkey(pSorter, &nKey);
  sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, r2);







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  void *pKey; int nKey;           /* Sorter key to compare pVal with */

  assert( pCsr->eCurType==CURTYPE_SORTER );
  pSorter = pCsr->uc.pSorter;
  r2 = pSorter->pUnpacked;
  pKeyInfo = pCsr->pKeyInfo;
  if( r2==0 ){

    r2 = pSorter->pUnpacked = sqlite3VdbeAllocUnpackedRecord(pKeyInfo);

    if( r2==0 ) return SQLITE_NOMEM_BKPT;
    r2->nField = nKeyCol;
  }
  assert( r2->nField==nKeyCol );

  pKey = vdbeSorterRowkey(pSorter, &nKey);
  sqlite3VdbeRecordUnpack(pKeyInfo, nKey, pKey, r2);