Periodic aria checkpoints prevent power management
Bug #859051 reported by
Philip Stoev
This bug affects 2 people
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
MariaDB |
Fix Released
|
Medium
|
Michael Widenius |
Bug Description
A customer reports that even in the absence of any workload, there are periodic writes to the Aria log file, which in turn prevents his laptop from sleeping.
It seems possible to not do a checkpoint if no queries have been executed since previous checkpoint.
Related branches
lp:~maria-captains/maria/5.2-bad
(Merged)
Changed in maria: | |
assignee: | nobody → Michael Widenius (monty) |
Changed in maria: | |
status: | In Progress → Fix Released |
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Having aria doing checkpoints should not stop a laptop from sleeping.
A 'sleep' will suspend all processes as first part of the sleep so mysqld should be doing nothing.
I have a Lenovo laptop running OpenSuse 11.3 and there is no problem with putting it to sleep even if mysqld is running (I am doing that frequently).
Here is how the checkpoint works:
repeat
Sleep 'checkpoint-time' seconds.
If enough new data in transaction log file
Do checkpoint
In other words, if there is nothing happening on the laptop, there is just a very short check once in a while if there is something that should be done (which is the feature that was requested).
InnoDB is doing something similar and there are dozen of processes in Linux that checks things once in a while (For example any 'clock' or process watching application will wake up once a second/minute but will not stop a laptop from sleeping).
Summary: I don't know of anything special in Aria checkpoint that would interfere with laptop sleep and I don't know of any way to test/prove that.