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author | Oleksandr Byelkin <sanja@mariadb.com> | 2018-01-12 18:17:55 +0100 |
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committer | Oleksandr Byelkin <sanja@mariadb.com> | 2018-01-14 10:49:56 +0100 |
commit | 5fe1d7d07611855963ea62ca39461289d8f8d25e (patch) | |
tree | cacc2b5537b2f8fa10db368a25fd3c8c5a2ac49b /sql/sql_class.h | |
parent | b75d767689aff33f4d6963169bb7044165494885 (diff) | |
download | mariadb-git-5fe1d7d07611855963ea62ca39461289d8f8d25e.tar.gz |
MDEV-14526: MariaDB keeps crashing under load when query_cache_type is changed
The problem was in such scenario:
T1 - starts registering query and locked QC
T2 - starts disabling QC and wait for UNLOCK
T1 - unlock QC
T2 - disable QC and destroy signals without waiting for query unlock
T1 a) - not yet unlocked query in qc and crash on attempt to unlock because
QC signals are destroyed
b) if above was done before destruction, it execute end_of results first
time at exit on after try_lock which see QC disables and return TRUE.
But it do not reset query_cache_tls->first_query_block which lead to
second call of end_of_result when diagnostic arena has already
inappropriate status (not is_eof()).
Fix is:
1) wait for all queries unlocked before destroying them by locking and
unlocking
2) remove query_cache_tls->first_query_block if QC disabled
Diffstat (limited to 'sql/sql_class.h')
0 files changed, 0 insertions, 0 deletions