704135 - metrics for read/write queries on buildbot and buildbot_schedulers databases on tm-b01-master01 and tm-b01-slave01

Status: RESOLVED FIXED

(Data & BI Services Team :: DB: MySQL, task)

Description

[Chris AtLee [:catlee]]

As per https://bugzilla.mozilla.org/show_bug.cgi?id=703365#c3, it would be really helpful to get some numbers on what our read/write ratio is like for our two main databases, both on the master and the slave.

Comment 1

[Sheeri Cabral [:sheeri]]

The best way to do this would be to turn slow query logging to have a 0 threshold for a sample period of time.  What would the best sample day/time/duration be?  (as it's a ratio, my guess is that a few hours, any day of the week, would be fine, but I defer to folks who know the app usage better than I do).

Comment 2

[Sheeri Cabral [:sheeri]]

Ugh, I completely forgot that MySQL 5.0.77 doesn't allow a long_query_time of 0, 1 is the lowest value.

I can just do this based on Com_ variables:

The master has about 81.8% reads, 18.2% writes (or a ratio of approx 4.5:1 reads:writes).

The slave has about 

The slave has about 72.5% *writes*, 17.5% reads, or a ration of approx 2.5:1 writes:reads.