/ Check-in [e2b10714]
Login
SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

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

Overview
Comment:Make the walIndexPage() routine about 3x faster by factoring out the seldom used reallocation logic into a separate subroutine.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256: e2b107141cd97bd4ab240748a9ce43fc2ec950ea74610697a4a7a3d7a6441e6b
User & Date: drh 2018-02-20 22:20:57
Context
2018-02-21
00:48
Remove an unnecessary memset(). check-in: e7b7f588 user: drh tags: trunk
2018-02-20
22:20
Make the walIndexPage() routine about 3x faster by factoring out the seldom used reallocation logic into a separate subroutine. check-in: e2b10714 user: drh tags: trunk
17:02
In the speed-check.sh script, make WAL mode the default. Add the --legacy option to do DELETE mode. Continue to use DELETE mode for long-term performance graphs since WAL mode was not always available, but use WAL mode for day-to-day performance measurements. check-in: cd816138 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/wal.c.

550
551
552
553
554
555
556
557




558
559
560
561
562
563
564
...
591
592
593
594
595
596
597










598
599
600
601
602
603
604
** so.  It is safe to enlarge the wal-index if pWal->writeLock is true
** or pWal->exclusiveMode==WAL_HEAPMEMORY_MODE.
**
** If this call is successful, *ppPage is set to point to the wal-index
** page and SQLITE_OK is returned. If an error (an OOM or VFS error) occurs,
** then an SQLite error code is returned and *ppPage is set to 0.
*/
static int walIndexPage(Wal *pWal, int iPage, volatile u32 **ppPage){




  int rc = SQLITE_OK;

  /* Enlarge the pWal->apWiData[] array if required */
  if( pWal->nWiData<=iPage ){
    int nByte = sizeof(u32*)*(iPage+1);
    volatile u32 **apNew;
    apNew = (volatile u32 **)sqlite3_realloc64((void *)pWal->apWiData, nByte);
................................................................................
      }
    }
  }

  *ppPage = pWal->apWiData[iPage];
  assert( iPage==0 || *ppPage || rc!=SQLITE_OK );
  return rc;










}

/*
** Return a pointer to the WalCkptInfo structure in the wal-index.
*/
static volatile WalCkptInfo *walCkptInfo(Wal *pWal){
  assert( pWal->nWiData>0 && pWal->apWiData[0] );







|
>
>
>
>







 







>
>
>
>
>
>
>
>
>
>







550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
...
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
** so.  It is safe to enlarge the wal-index if pWal->writeLock is true
** or pWal->exclusiveMode==WAL_HEAPMEMORY_MODE.
**
** If this call is successful, *ppPage is set to point to the wal-index
** page and SQLITE_OK is returned. If an error (an OOM or VFS error) occurs,
** then an SQLite error code is returned and *ppPage is set to 0.
*/
static SQLITE_NOINLINE int walIndexPageRealloc(
  Wal *pWal,               /* The WAL context */
  int iPage,               /* The page we seek */
  volatile u32 **ppPage    /* Write the page pointer here */
){
  int rc = SQLITE_OK;

  /* Enlarge the pWal->apWiData[] array if required */
  if( pWal->nWiData<=iPage ){
    int nByte = sizeof(u32*)*(iPage+1);
    volatile u32 **apNew;
    apNew = (volatile u32 **)sqlite3_realloc64((void *)pWal->apWiData, nByte);
................................................................................
      }
    }
  }

  *ppPage = pWal->apWiData[iPage];
  assert( iPage==0 || *ppPage || rc!=SQLITE_OK );
  return rc;
}
static int walIndexPage(
  Wal *pWal,               /* The WAL context */
  int iPage,               /* The page we seek */
  volatile u32 **ppPage    /* Write the page pointer here */
){
  if( pWal->nWiData<=iPage || (*ppPage = pWal->apWiData[iPage])==0 ){
    return walIndexPageRealloc(pWal, iPage, ppPage);
  }
  return SQLITE_OK;
}

/*
** Return a pointer to the WalCkptInfo structure in the wal-index.
*/
static volatile WalCkptInfo *walCkptInfo(Wal *pWal){
  assert( pWal->nWiData>0 && pWal->apWiData[0] );