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:

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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)?

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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@mariadb.org

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