maria-developers team mailing list archive

[Alexey Botchkov <holyfoot@xxxxxxxxxxxx>]

> This seems fairly obvious, that it should.
> But why MySQL doesn't have this bug (despite not resetting
> m_extra_prepare_for_update)?

The difference is in the ha_partition::late_extra_cache() function
MySQL:
  if (m_extra_prepare_for_update)
  {
    (void) file->extra(HA_EXTRA_PREPARE_FOR_UPDATE);
  }

Maria:
  if (m_extra_prepare_for_update)
  {
    DBUG_ASSERT(m_extra_cache);
    (void) file->extra(HA_EXTRA_PREPARE_FOR_UPDATE);
  }

And that DBUG_ASSERT() actually does the crash.

MySQL just blindly does the file->extra(HA_EXTRA_PREPARE_FOR_UPDATE)
even for that 'SELECT * FROM t2;' query.

Best regards.
HF




21.12.2016 0:35, Sergei Golubchik wrote:
> Hi, Alexey!
>
> On Dec 20, Alexey Botchkov wrote:
> > revision-id: 0310b444dba1b9cbd6921963dd3bff689ca23a24 (mariadb-5.5.53-34-g0310b44)
> > parent(s): f23b41b9b8a30e0e54a1ec7a8923057b0e57e0f5
> > committer: Alexey Botchkov
> > timestamp: 2016-12-20 00:24:20 +0400
> > message:
> >
> > MDEV-10418 Assertion `m_extra_cache' failed in ha_partition::late_extra_cache(uint)
> >
> >          The m_extra_prepare_for_update parameter should be set to FALSE
> >          as the query ends.
> This seems fairly obvious, that it should.
> But why MySQL doesn't have this bug (despite not resetting
> m_extra_prepare_for_update)?
>
> > diff --git a/sql/ha_partition.cc b/sql/ha_partition.cc
> > index 15fa7d1..4374354 100644
> > --- a/sql/ha_partition.cc
> > +++ b/sql/ha_partition.cc
> > @@ -6667,6 +6667,7 @@ int ha_partition::reset(void)
> >     DBUG_ENTER("ha_partition::reset");
> >     if (m_part_info)
> >       bitmap_set_all(&m_part_info->used_partitions);
> > +  m_extra_prepare_for_update= FALSE;
> >     file= m_file;
> >     do
> >     {
> Regards,
> Sergei
> Chief Architect MariaDB
> and security@xxxxxxxxxxx
>
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