maria-developers team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

Hi, Sergei!

On Nov 07, Sergei Petrunia wrote:
> revision-id: 1a4031d9c8f314896daf8f7c19d6172b9bba313b (mariadb-10.3.10-49-g1a4031d9c8f)
> parent(s): e058a251c10350f3727ca1df022dc5786933535b
> author: Sergei Petrunia
> committer: Sergei Petrunia
> timestamp: 2018-11-07 11:58:30 +0300
> message:
> 
> MDEV-17297: stats.records=0 for a table of Archive engine when it has rows, when we run ANALYZE command
... 
> diff --git a/storage/archive/ha_archive.cc b/storage/archive/ha_archive.cc
> index 487c0038239..9d7f7e66b28 100644
> --- a/storage/archive/ha_archive.cc
> +++ b/storage/archive/ha_archive.cc
> @@ -1737,6 +1721,38 @@ int ha_archive::info(uint flag)
>  }
>  
>  
> +int ha_archive::external_lock(THD *thd, int lock_type)
> +{
> +  if (lock_type == F_RDLCK)
> +  {
> +    // We are going to read from the table. Flush any pending writes that we
> +    // may have
> +    flush_and_clear_pending_writes();
> +  }
> +  return 0;
> +}

This is somewhat unexpected. Normally buffers are flushed at the end of
a statement, on F_UNLCK. For example, you'll have a better chance of
surviving a crash (or kill -9).

Otherwise I don't see much of a difference, so do it as you like.

Shouldn't it go into 5.5, as the earliest affected version?

> +void ha_archive::flush_and_clear_pending_writes()
> +{
> +  mysql_mutex_lock(&share->mutex);
> +  if (share->dirty)
> +  {
> +    DBUG_PRINT("ha_archive", ("archive flushing out rows for scan"));
> +    DBUG_ASSERT(share->archive_write_open);
> +    azflush(&(share->archive_write), Z_SYNC_FLUSH);
> +    share->dirty= FALSE;
> +  }
> +
> +  /* 
> +    This should be an accurate number now, though bulk and delayed inserts can
> +    cause the number to be inaccurate.
> +  */
> +  stats.records= share->rows_recorded;
> +  mysql_mutex_unlock(&share->mutex);
> +}

Regards,
Sergei
Chief Architect MariaDB
and security@xxxxxxxxxxx