[pmmail-list] time to clear trash - performance

[PMMail OS/2 Support]

On Sat, 06 Oct 2001 09:01:15 -0300, PMMail OS/2 Support wrote:

>You misunderstood. I meant that when I tested it, it was not possible
>for *me* to reproduce it. I understand the details of the problem.

Or, maybe I'm just dumb.

I have just tested this again and now I *am* able to reproduce it
here. This means that either 1) something has changed with my test
system or 2) I was wrong in the first place (didn't test properly or
didn't observe accurately).

Whatever the explanation for my mistake, here are the test results I
just gathered. They are not exhaustive but should serve as a sort of
benchmark. I am running a PIII 500mhz with 128 meg of RAM running
OS/2 Warp 4 with FP 12 or thereabouts and nothing else running
(except a few WPS enhancers).

==== Begin Results ====
Test 1

1. create 3,294 *.msg files in a directory
2. open PMMail/2
3. reindex that directory
4. move all messages to Trash folder
5. set PMMail/2 to empty all messages from Trash on shutdown
6. shut down

Time: 1 minute, 33 seconds.
CPU usage: fluctuating between 26% and 71%

NOTE 1: Reindexing inbox folder took about 3 minutes and hovered
between 90% and 100%.
NOTE 2: Moving messages from inbox folder to trash folder (with
Delete button) took approximately 30 seconds and did not tax CPU more
than 10%

Test 2

1. create 3,294 *.msg files in a directory
2. open PMMail/2
3. reindex that directory
4. move all messages to Trash
5. set PMMail/2 to empty messages older than 4 days from Trash on
shutdown
6. shutdown

Time: 10 minutes, 11 seconds.
CPU usage: about 98% most of the time

NOTE 1: There were 2,125 messages in the Trash folder with dates more
than 4 days old.
NOTE 2: The system was more or less unusable while this was going on.
NOTE 3: To delete the remaining 1,169 messages from the Trash folder
without closing PMMail took 1 minute 55 seconds and fluctuated
between 60% and 100% CPU usage.

Test 3

1. create 3,294 *.msg files in a directory
2. from an OS/2 command prompt type "del *.msg" and press Enter

Time: 1 minute, 36 seconds.
CPU usage: fluctuating between 26% and 71%

NOTE 1: This is roughly the same as Test 1.
===== End Results =====

Obviously the "check if older than" function slows things down (by
about 7 times). However, at only 10 minutes to process > 3,000
messages, I have to wonder how much this could be sped up. The
software must read part of each message, after all, rather than just
deleting it. I will ask Peter.

I could not generate results where it took hours to perform the
shutdown but that's irrelevant. The 10 minute system freeze is enough
of a performance problem that it needs to be addressed somehow and,
presumably, whether it's 10 minutes or 120 minutes, the cause is the
same.

So, now at least we can reproduce the problem. No promise yet about
when a fix will show up though.


--
Trevor Smith
PMMail/2 Technical Support
pmmailos2@blueprintsoftwareworks.com


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