jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 24133
Joined: Sat Jul 30, 2011 7:41 pm

Re: Cannot Search Forum

Tue Oct 30, 2018 11:33 am

pcmanbob wrote:
Tue Oct 30, 2018 11:22 am
Well done jamesh for finding a fix and restoring the forum to a usable state.
Wasn't me - please don't assign me any credit for this one!!
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
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andrum99
Posts: 924
Joined: Fri Jul 20, 2012 2:41 pm

Re: Cannot Search Forum

Tue Oct 30, 2018 11:43 am

jamesh wrote:
Tue Oct 30, 2018 10:45 am
Hello all,

You will hopefully have noticed that the forums is now behaving itself. The eagle eyed amongst you will have noticed that the "Number of users online" section at the bottom of the index page has disapeared. It appears we have been suffering from this https://www.phpbb.com/community/viewtopic.php?t=2124014 issue which was soaking up >80% of the forum server performance just to work out the number of users online.

Not sure if a blog post fully explaining things will appear, but for now, we* have hacked phpbb to get rid of the problem, so the forum should be a LOT faster, and now capable of about 10 times the throughput prior to the issue appearing.

Interesting that this phpbb issue was reported in 2011. And has never been fixed.


*we != me. This is way out of my area of expertise.
That does look like a pretty staggering performance bug in phpbb: a piece of code in every page that causes the database to do a full table scan every time the page is accessed. I'm guessing the fix is to just rip out the code that tries to count the number of online users, which is not really something you need on the front end, although in the admin interface it might still be useful. Although, a quick read of the MySQL docs (https://dev.mysql.com/doc/refman/5.6/en ... type_range) suggests that it can actually use indexes for range queries, so perhaps the timestamp column is not indexed.

I hope the developers of phpbb are a bit more on the ball when it comes to security :o

pcmanbob
Posts: 7259
Joined: Fri May 31, 2013 9:28 pm
Location: Mansfield UK

Re: Cannot Search Forum

Tue Oct 30, 2018 12:10 pm

jamesh wrote:
Tue Oct 30, 2018 11:33 am
pcmanbob wrote:
Tue Oct 30, 2018 11:22 am
Well done jamesh for finding a fix and restoring the forum to a usable state.
Wasn't me - please don't assign me any credit for this one!!
Then please pass the thanks on to who ever deserves it.
We want information… information… information........................no information no help
The use of crystal balls & mind reading are not supported

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 24133
Joined: Sat Jul 30, 2011 7:41 pm

Re: Cannot Search Forum

Tue Oct 30, 2018 12:41 pm

pcmanbob wrote:
Tue Oct 30, 2018 12:10 pm
jamesh wrote:
Tue Oct 30, 2018 11:33 am
pcmanbob wrote:
Tue Oct 30, 2018 11:22 am
Well done jamesh for finding a fix and restoring the forum to a usable state.
Wasn't me - please don't assign me any credit for this one!!
Then please pass the thanks on to who ever deserves it.
Mythic Beasts, I believe. https://www.mythic-beasts.com/
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
“I think it’s wrong that only one company makes the game Monopoly.” – Steven Wright

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Burngate
Posts: 6091
Joined: Thu Sep 29, 2011 4:34 pm
Location: Berkshire UK Tralfamadore
Contact: Website

Re: Cannot Search Forum

Tue Oct 30, 2018 6:39 pm

Brilliant - even the "Your posts" is working nice and fast - thank you.
And to my local shop that's got clotted cream back on the shelves. I wonder if they ever log on here?

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 24133
Joined: Sat Jul 30, 2011 7:41 pm

Re: Cannot Search Forum

Tue Oct 30, 2018 8:56 pm

Burngate wrote:
Tue Oct 30, 2018 6:39 pm
Brilliant - even the "Your posts" is working nice and fast - thank you.
And to my local shop that's got clotted cream back on the shelves. I wonder if they ever log on here?
I have to say it seems a lot faster to me. Nice find by Mythic.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
“I think it’s wrong that only one company makes the game Monopoly.” – Steven Wright

DirkS
Posts: 10015
Joined: Tue Jun 19, 2012 9:46 pm
Location: Essex, UK

Re: Cannot Search Forum

Tue Oct 30, 2018 9:04 pm

jamesh wrote:
Tue Oct 30, 2018 8:56 pm
Burngate wrote:
Tue Oct 30, 2018 6:39 pm
Brilliant - even the "Your posts" is working nice and fast - thank you.
And to my local shop that's got clotted cream back on the shelves. I wonder if they ever log on here?
I have to say it seems a lot faster to me. Nice find by Mythic.
Agreed. As I mentioned before I find it's especially noticeable with the 'unanswered topics'. Was quite slow in the past, but now it's showing almost instantly.

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