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Overview
Comment:Minor performance tweaks to the pager.
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SHA1: 9ae1f9ce7ea6beaeddc3711080b3796e05acc4f8
User & Date: drh 2013-08-21 22:54:55.506
Context
2013-08-21
23:42
Simplify the btreeGetPage() routine so that it uses a single flag parameter in place of two boolean parameters. (check-in: 617e23ec28 user: drh tags: trunk)
22:54
Minor performance tweaks to the pager. (check-in: 9ae1f9ce7e user: drh tags: trunk)
22:09
Refactor the sqlite3_randomness() implementation for improved performance. (check-in: 4144dffb57 user: drh tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/pager.c.
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** or more open savepoints for which:
**
**   * The page-number is less than or equal to PagerSavepoint.nOrig, and
**   * The bit corresponding to the page-number is not set in
**     PagerSavepoint.pInSavepoint.
*/
static int subjRequiresPage(PgHdr *pPg){
  Pgno pgno = pPg->pgno;
  Pager *pPager = pPg->pPager;


  int i;


  for(i=0; i<pPager->nSavepoint; i++){
    PagerSavepoint *p = &pPager->aSavepoint[i];
    if( p->nOrig>=pgno && 0==sqlite3BitvecTest(p->pInSavepoint, pgno) ){
      return 1;

    }
  }
  return 0;
}

/*
** Return true if the page is already in the journal file.








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** or more open savepoints for which:
**
**   * The page-number is less than or equal to PagerSavepoint.nOrig, and
**   * The bit corresponding to the page-number is not set in
**     PagerSavepoint.pInSavepoint.
*/
static int subjRequiresPage(PgHdr *pPg){

  Pager *pPager = pPg->pPager;
  PagerSavepoint *p;
  Pgno pgno;
  int i;
  if( pPager->nSavepoint ){
    pgno = pPg->pgno;
    for(i=0; i<pPager->nSavepoint; i++){
      p = &pPager->aSavepoint[i];
      if( p->nOrig>=pgno && 0==sqlite3BitvecTest(p->pInSavepoint, pgno) ){
        return 1;
      }
    }
  }
  return 0;
}

/*
** Return true if the page is already in the journal file.
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  Pgno pgno = pPg->pgno;       /* Page number to read */
  int rc = SQLITE_OK;          /* Return code */
  int pgsz = pPager->pageSize; /* Number of bytes to read */

  assert( pPager->eState>=PAGER_READER && !MEMDB );
  assert( isOpen(pPager->fd) );

  if( NEVER(!isOpen(pPager->fd)) ){
    assert( pPager->tempFile );
    memset(pPg->pData, 0, pPager->pageSize);
    return SQLITE_OK;
  }

#ifndef SQLITE_OMIT_WAL
  if( iFrame ){
    /* Try to pull the page from the write-ahead log. */
    rc = sqlite3WalReadFrame(pPager->pWal, iFrame, pgsz, pPg->pData);
  }else
#endif
  {








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  Pgno pgno = pPg->pgno;       /* Page number to read */
  int rc = SQLITE_OK;          /* Return code */
  int pgsz = pPager->pageSize; /* Number of bytes to read */

  assert( pPager->eState>=PAGER_READER && !MEMDB );
  assert( isOpen(pPager->fd) );







#ifndef SQLITE_OMIT_WAL
  if( iFrame ){
    /* Try to pull the page from the write-ahead log. */
    rc = sqlite3WalReadFrame(pPager->pWal, iFrame, pgsz, pPg->pData);
  }else
#endif
  {
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