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Category Archives: mysql
Hash of shame
I may retract this post, I may have been way too incorrect here, not sure yet. Hash maps were invented sixty years ago, apparently. MySQL reinvented them. Original idea was too fancy and too good, I guess. It allowed very … Continue reading
Posted in mysql
8 Comments
MySQL 5.6 @ Facebook development tree Steaphan is a hero (well, everyone else on database engineering team are too) and he is driving efforts to publish MySQL 5.6 changes we’re making to the open. Now they’re on the github (yet … Continue reading
On performance schemas
You should probably read Marc Alff’s post about configuring Performance Schema in MySQL 5.6. We wrote another guide, how to start using user/table/index statistics first introduced in Google patch, now part of various MySQL branches and forks: Start MySQL
Posted in mysql
3 Comments
The saddest bug of them all (SQL is dead?)
From time to time I will observe servers wasting lots of CPU when doing batch row operations. In perf top it will look like this: 8.24% mysqld [.] Arg_comparator::compare_int_unsigned() 7.17% mysqld [.] Item_cond_and::val_int() 4.37% mysqld [.] Item_field::val_int() 4.37% mysqld [.] … Continue reading
on wikipedia and mariadb
There’s some media coverage about Wikipedia switching to MariaDB, I just wanted to point out that performance figures cited are somewhat incorrect and don’t attribute gains to correct authors. Proper performance evaluation should include not just MariaDB 5.5 but Oracle’s … Continue reading
Posted in mysql, wikitech
20 Comments
on seconds_behind_master sleuthing
With large enough infrastructure it gets a bit more and more complicated to detect whether an incident or a problem is real systems problem or a monitoring glitch. This is a story of one such investigation. With a sufficiently large … Continue reading
replication prefetching revisited
Been a while since I wrote about replication work we did. Fake changes based approach was huge success, and now our prefetching has lots of coverage, where standard SELECTs cannot reach. We’re running our systems at replication pressure, where not … Continue reading
MySQL is bazillion times faster than MemSQL
I don’t like stupid benchmarks, as they waste my time. I don’t like stupid marketing, as it wastes my time too. Sometimes I succumb to those things, and now in return I want to waste your time a bit. So, … Continue reading
Posted in mysql
27 Comments
On binlogs and datacenters
Once MySQL is deployed inside a datacenter environment (i.e. forms a cloud ;-), major feature in it becomes replication. It is used to maintain hot copies, standby copies, read-only copies, invalidate external systems, replicate to external systems, etc. If this … Continue reading
MySQL is doomed?
Percona’s version of MySQL Conference this year was awesome, and there were some great keynotes there, I’ll high-light two of them. One was called “Future Perfect: The Road Ahead for MySQL” and had a vendor panel of “Industry leaders from … Continue reading
Posted in mysql
14 Comments
