SQLite

Check-in [044b0b65e7]
Login

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

Overview
Comment:In a checkpoint, figure out if it is possible to checkpoint any frames at all before creating the wal-iterator.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256: 044b0b65e716bffeddedbd1b0360c4c332f6d2359167c1d327a5ff96539474cb
User & Date: dan 2018-03-02 16:52:47.523
References
2018-03-05
23:23
Fix walIteratorInit() so that it always leaves the iterator as a NULL pointer if an OOM occurs. This fixes an assertion fault introduced by check-in [044b0b65e716bff]. (check-in: e5ce256aa1 user: drh tags: trunk)
Context
2018-03-02
20:00
In sqlite3_checker, wrap the call to "SELECT checkfreelist()" in a transaction. (check-in: 02906e55d7 user: dan tags: trunk)
17:59
Update this branch with recent checkpoint related changes from trunk. (check-in: fb6b793860 user: dan tags: begin-concurrent)
16:52
In a checkpoint, figure out if it is possible to checkpoint any frames at all before creating the wal-iterator. (check-in: 044b0b65e7 user: dan tags: trunk)
15:42
Optimize the obscure case of running a checkpoint against a very large wal file for which a large percentage of the frames have already been checkpointed. (check-in: 0f5057dffa user: dan tags: trunk)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/wal.c.
︙︙
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805


  szPage = walPagesize(pWal);
  testcase( szPage<=32768 );
  testcase( szPage>=65536 );
  pInfo = walCkptInfo(pWal);
  if( pInfo->nBackfill<pWal->hdr.mxFrame ){

    /* Allocate the iterator */
    rc = walIteratorInit(pWal, pInfo->nBackfill, &pIter);
    if( rc!=SQLITE_OK ){
      return rc;
    }
    assert( pIter );

    /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
    ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
    assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );

    /* Compute in mxSafeFrame the index of the last frame of the WAL that is
    ** safe to write into the database.  Frames beyond mxSafeFrame might
    ** overwrite database pages that are in use by active readers and thus








<
<
<
<
<
<
<








1785
1786
1787
1788
1789
1790
1791







1792
1793
1794
1795
1796
1797
1798


  szPage = walPagesize(pWal);
  testcase( szPage<=32768 );
  testcase( szPage>=65536 );
  pInfo = walCkptInfo(pWal);
  if( pInfo->nBackfill<pWal->hdr.mxFrame ){








    /* EVIDENCE-OF: R-62920-47450 The busy-handler callback is never invoked
    ** in the SQLITE_CHECKPOINT_PASSIVE mode. */
    assert( eMode!=SQLITE_CHECKPOINT_PASSIVE || xBusy==0 );

    /* Compute in mxSafeFrame the index of the last frame of the WAL that is
    ** safe to write into the database.  Frames beyond mxSafeFrame might
    ** overwrite database pages that are in use by active readers and thus
︙︙
1828
1829
1830
1831
1832
1833
1834

1835





1836
1837
1838
1839
1840
1841
1842

          xBusy = 0;
        }else{
          goto walcheckpoint_out;
        }
      }
    }


    if( pInfo->nBackfill<mxSafeFrame





     && (rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(0),1))==SQLITE_OK
    ){
      i64 nSize;                    /* Current size of database file */
      u32 nBackfill = pInfo->nBackfill;

      pInfo->nBackfillAttempted = mxSafeFrame;









>
|
>
>
>
>
>








1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841

          xBusy = 0;
        }else{
          goto walcheckpoint_out;
        }
      }
    }

    /* Allocate the iterator */
    if( pInfo->nBackfill<mxSafeFrame ){
      rc = walIteratorInit(pWal, pInfo->nBackfill, &pIter);
      assert( rc==SQLITE_OK || pIter==0 );
    }

    if( pIter
     && (rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(0),1))==SQLITE_OK
    ){
      i64 nSize;                    /* Current size of database file */
      u32 nBackfill = pInfo->nBackfill;

      pInfo->nBackfillAttempted = mxSafeFrame;
︙︙