AlgebraicMirror
Oct 18, 2011Altostratus
Strange F5 ASM Sawtooth CPU Graph
A couple of my ASM 3600s have odd sawtooth patterns on their CPU performance graphs. Approximately every three minutes, CPU spikes, and then shortly afterword goes back down.
Using top, I was able to determine that mysqld is causing this. From within mysql, I used the "show processlist;" command to see what was being run. It's not one statement, but several, and the same ones are run in the same order each time. This tells me some kind of a script is using mysql every three minutes, and since there are no stored procedures in the ASM database, it must be a script external to mySQL.
Has anyone run into anything like this before? I have three ASMs in the same production pool, and all are on 10.2.2 HF3. One was just rebuilt from scratch and does not have this problem, while the two that were simply upgraded do (they had this before the upgrade as well). Here are some of the statements I saw mysql running... any idea what is causing this or how to turn it off? Or even how I might investigate further?
UPDATE PLC.LRN_NEGSIG_SIGNATURES A
LEFT JOIN PLC.PL_OBJECTS AS F
ON (A.obj_crc = F.obj_crc
UPDATE PLC.LRN_NEGSIG_SIGNATURES AS A
JOIN PLC.PL_PARAM_NEGSIG_SIGNATURES AS B
ON (A.param_at
UPDATE PLC.LRN_NEGSIG_SIGNATURES AS A
LEFT JOIN PLC.PL_GLOBAL_PARAMS AS B
ON (((A.param_name
etc.