We recently upgraded from MariaDB 5.5 to MariaDB 10.5
Since doing so, we have a couple of
select queries appearing in the slow query log when we backup databases using mysqldump.
One of the tables is an InnoDB table with 125,000 records. The other is a MyISAM table with 220,000 records.
I guess this might not seem like any great concern, however for many years we never had anything in the slow query log related to mysqldump. So I am wondering if we should be worried? Did the behaviour of mysqldump change between versions 5.5 and 10.5, or could there be some other local setting that we perhaps had optimsied previously, that now isn't?
Our slow query time is set to 5 seconds, which is what it was previously. The offending queries are taking just under 6 seconds.
After further investigation, it turns out we are piping mysqldump through gzip, to compress the resulting dump files. Removing gzip from the equation results in each dump completing in 3 seconds or less.
The fact still remains that our setup remained unchanged other than the upgrade from MariaDB 5 to 10, and this didn't seem to be an issue previously.
In any case, whilst piping to gzip results in a nice "one liner", I have changed it to dump the files as plain text, then gzip them afterwards. I feel better knowing that the dump queries complete much faster, and aren't held up by gzip.