I've been doing some testing with various versions of MySQL and MariaDB regarding slow log rotation. And it looks like MariaDB (tested 10.4, 10.5, 10.6 so far) suffers from a bug. Setup: sloq_query_log=1 long_query_time=0 # sysbench oltp_read_write --threads=$(nproc) Action: mv slow.log slow.log.1 MariaDB [(none)]> flush slow logs; ^^ This never returns (never as in I haven't tried waiting for > 10 minutes). On MySQL 5.5 this is instantaneous. On 5.6 - 8.0 it takes a few seconds, worst case I measured over the weekend is 77s, which is pretty terrible, but with MariaDB 10.3 - 10.6 it never seems to complete at all. If I kill sysbench, it completes immediately. On 10.3 it works, in line with MySQL 5.6 - 8.0. This seems like a rather significant bug.
Correction: - with MariaDB 10.3 - 10.6 it never seems to complete at all. + with MariaDB 10.4 - 11.4 it never seems to complete at all. On Sun, Nov 17, 2024 at 6:44 PM Gordan Bobic <gordan.bobic@gmail.com> wrote:
I've been doing some testing with various versions of MySQL and MariaDB regarding slow log rotation. And it looks like MariaDB (tested 10.4, 10.5, 10.6 so far) suffers from a bug.
Setup: sloq_query_log=1 long_query_time=0
# sysbench oltp_read_write --threads=$(nproc)
Action: mv slow.log slow.log.1
MariaDB [(none)]> flush slow logs;
^^ This never returns (never as in I haven't tried waiting for > 10 minutes).
On MySQL 5.5 this is instantaneous. On 5.6 - 8.0 it takes a few seconds, worst case I measured over the weekend is 77s, which is pretty terrible, but with MariaDB 10.3 - 10.6 it never seems to complete at all.
If I kill sysbench, it completes immediately.
On 10.3 it works, in line with MySQL 5.6 - 8.0.
This seems like a rather significant bug.
Additional: Whatever the cause, it got substantially worse in 10.4.34. With 10.4.0-10.4.33 it isn't great, but it typically finishes in between a few seconds up to 5 minutes. With 10.4.34, it never finishes in the seconds, I saw only one example in hours of testing where it `flush slow logs;` under heavy load completed in under a minute, in most cases it takes upward of 10 minutes. On Sun, Nov 17, 2024 at 6:56 PM Gordan Bobic <gordan.bobic@gmail.com> wrote:
Correction: - with MariaDB 10.3 - 10.6 it never seems to complete at all. + with MariaDB 10.4 - 11.4 it never seems to complete at all.
On Sun, Nov 17, 2024 at 6:44 PM Gordan Bobic <gordan.bobic@gmail.com> wrote:
I've been doing some testing with various versions of MySQL and MariaDB regarding slow log rotation. And it looks like MariaDB (tested 10.4, 10.5, 10.6 so far) suffers from a bug.
Setup: sloq_query_log=1 long_query_time=0
# sysbench oltp_read_write --threads=$(nproc)
Action: mv slow.log slow.log.1
MariaDB [(none)]> flush slow logs;
^^ This never returns (never as in I haven't tried waiting for > 10 minutes).
On MySQL 5.5 this is instantaneous. On 5.6 - 8.0 it takes a few seconds, worst case I measured over the weekend is 77s, which is pretty terrible, but with MariaDB 10.3 - 10.6 it never seems to complete at all.
If I kill sysbench, it completes immediately.
On 10.3 it works, in line with MySQL 5.6 - 8.0.
This seems like a rather significant bug.
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Gordan Bobic