We are running several Atlassian applications against a single MySQL server. We're seeing several thousand queries per second on a regular basis. In fact, the lowest count is 1200 q/s. It spikes at 3.7 q/s.
Breaking down the query log we have found that 62% of the total query traffic comes from 'Com_' queries, specifically: set, rollback, and commit commands.
All apps are tied into Crowd, which in turn is tied into our LDAP server. About 22,000 users are being synchronized from LDAP into Crowd, and subsequently into the other Atlassian apps (JIRA, Confluence, Fisheye, Bamboo).
From the graph of this behavior it seems to be associated with our 20-minute synchronization interval across the tools. It spikes for about that amount of time then settles back down to 1.2 Kq/s.
Is this normal behavior for the Atlassian tools? Does this metric affect performance of useful queries (like SELECT - 17% of the total query traffic)?
__ Questions ___________________________________________________________ Total 2.12G 1.4k/s Com_ 1.31G 866.9/s %Total: 61.92 QC Hits 416.53M 275.0/s 19.64 DMS 390.87M 258.0/s 18.43 COM_QUIT 610.59k 0.4/s 0.03 -Unknown 166.96k 0.1/s 0.01 Slow 10 s 129 0.0/s 0.00 %DMS: 0.00 Log: OFF DMS 390.87M 258.0/s 18.43 SELECT 360.03M 237.7/s 16.97 92.11 UPDATE 30.53M 20.2/s 1.44 7.81 INSERT 234.41k 0.2/s 0.01 0.06 DELETE 71.78k 0.0/s 0.00 0.02 REPLACE 0 0/s 0.00 0.00 Com_ 1.31G 866.9/s 61.92 set_option 711.73M 469.8/s 33.55 rollback 312.11M 206.0/s 14.71 commit 288.07M 190.2/s 13.58
Hmm, you might be right. For a huge amount of use it could go up higher. But I believe that this should not give you problems ( if the machine were MySQL is hosted is robust). Otherwise we would see a lot of users complaining that Crowd can't handle large amount of users, which I have yet to see :)
From lots of customers using Crowd, few complained about performance, which turned out to be memory, so I believe that its unlikely to your MySQL to be the bottleneck for you.
All Atlassian products rely heavily on the database. For every action performed there is a select query. For every search or update there is another set of queries running. So I believe that this is a normal behavior FOR 22k users, as you said you have.
You can monitor this at non working hours, or when there is less users in the company. But to my belief its normal. Unless its affecting your performance.
Hope this helps!
Thanks. I'm not so much worried about the "real" work happening via SELECT/UPDATE/INSERT/etc. statements. It just seems unusual to have such a high percentage of Com_ overhead (set_option, rollback, commit).
It's traffic like the following that concerns me (but hasn't seemed to cause any issues):
610081 Query update cwd_token set directory_id=294913, entity_name='JIMAPLES', rand... 610081 Query commit 610081 Query rollback 610081 Query SET autocommit=1 610081 Query SET autocommit=0 610081 Query select this_.id as id28_0_, this_.application_name as applicat2_28_... 610081 Query commit 610081 Query rollback 610081 Query SET autocommit=1 610081 Query SET autocommit=0 610081 Query commit 610081 Query rollback 610081 Query SET autocommit=1 610081 Query SET autocommit=0 610081 Query select this_.id as id28_0_, this_.application_name as applicat2_28_0_... 610081 Query commit 610081 Query rollback 610081 Query SET autocommit=1 610081 Query SET autocommit=0
I worry about scalability. If MySQL is serving 3 Kq/s now... what happens when we have heavy use of this system by the enterprise? Maybe nothing. Perhaps this is just the normal activity for a crowd-enabled installation.
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