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8.8.15: very slow when accessing shared folders

Posted: Thu May 21, 2020 10:22 am
by maxxer
Hi.
We recently migrated an old 8.0.5 to 8.8.15 on a new server (more powerful).

Since the migration users accessing shared (mounted) accounts experience an extremely slow Web UI into those folders, sometimes locking the browser, sometimes hanging with the "loading" dialog.
Logging into the shared account is fast, it's slow only when accessed as mounted. Those shared account have 10y of email, thousands in number, but as said logging directly doesn't show problems.

Checking on the server (Ubuntu 18.04, dedicated to Zimbra) doesn't show high usage. I occasionally see MySQL spiking for a minute or two on two cores.

Anyone having the same issue?
thanks

Re: 8.8.15: very slow when accessing shared folders

Posted: Thu May 21, 2020 3:50 pm
by maxxer
I found the query being dead slow is this:

Code: Select all

SELECT mi.id, mi.type, mi.parent_id, mi.folder_id, mi.prev_folders, mi.index_id,mi.imap_id, mi.date, mi.size, mi.locator, mi.blob_digest, mi.unread, mi.flags, mi.tag_names, mi.subject,mi.name, mi.metadata, mi.mod_metadata, mi.change_date, mi.mod_content, mi.uuid, mi.unread AS sortcol
FROM mboxgroup19.mail_item AS mi
WHERE mi.mailbox_id = 19 AND ((mi.type = 0x05 OR mi.type = 0x10) AND mi.folder_id = 2) ORDER BY sortcol DESC, mi.id DESC LIMIT 0,1003

It's being executed several times with different LIMIT, and can run for minutes.

What puzzles me is sorting for mi.unread... Even if on the UI I set sorting for received date the query still uses that field.

The query itself doesn't seem to be the only problem... It's run and re-run several times in loop! Once reaches a certain LIMIT value it starts again from 0!

Re: 8.8.15: very slow when accessing shared folders

Posted: Fri May 22, 2020 9:21 am
by gabrieles
user's zimbraPrefSortOrder are already wiped?

Re: 8.8.15: very slow when accessing shared folders

Posted: Wed May 27, 2020 4:35 am
by maxxer
Thanks for the suggestion, it's hard to tell as the problem happens intermittently during the day but wiping sort horder might have had some impact. The folder opening is still slow, occasionally it improved a bit but it's not definitely resolved.

What makes me crazy is that opening the same mailbox alone, not as mounted dir, is fast.

Re: 8.8.15: very slow when accessing shared folders

Posted: Fri May 29, 2020 9:25 am
by maxxer
Thanks again for the suggestion, some users reported significant improvement now.

I found this old thread with the same problem and your suggestion.
There's also an open bug