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Posted by Sandman on 11/23/06 20:17
In article <4565b82b$0$325$e4fe514c@news.xs4all.nl>,
Erwin Moller
<since_humans_read_this_I_am_spammed_too_much@spamyourself.com>
wrote:
> First: Prefetching all members into memory for each page where you need one
> or two members is absolutely a no-go. You must change that of course.
> Just fetch the information you need WHEN you need it.
Yes, but if I need to fetch information for 100 members on one page
making 100 individual SQL queries is also a no-go.
> If I understand correctly your main problem lies in the fact you must fetch
> the online/offline information for each possible user.
> Correct?
No, there are lots of other information also being fetched. The
online/offline status is kept in a seperate db and isn't a problem at
all actually. Nicknames, labels, ages, full name and such things are
what is needed. All of that is in the member DB
> This is how I solved this problem when I was in a similar situation:
> (a rough quick overview to show the idea)
>
> 1) Create a table like
> CREATE TABLE tblOnlineUsers(
> userid integer REFERENCES tbluser.userid,
> lastActive timestamp
> )
>
> 2) Whenever a logged-in user does something, update the timestamp in this
> table for that userid.
That's exactly what I'm doing.
> 3) When you are on a page that needs to know the status of online users,
> just load it into a array with a query like:
> SELECT userid FROM tblOnlineUsers WHERE (
> lastActive > XXX
> )
>
> Where XXX is (now - your sessiontimeout).
>
> Now you need some logic to delete the userids for stale users.
I do that in my five minute aggregation script (that aggregates lots
of stuff for the site). There I delete from member.surfers where
datetime < date_sub(now(), interval 10 minute)
> (Users that didn't log out, but just closed their browser or walked away to
> get a nice good lunch of three hours)
> eg
> When a random number between 0 and 1 is smaller than 0.1 you delete all
> records older than the sessiontimeout.
>
> You also need to make sure the userid in that table is unique.
>
> But this solution has the advantage that:
> - You don't load all users into memory for each scriptinvocation
> - Your tblOnlineUsers can be searched very quickly.
Yeah, I'm already doing that. I still need some way to get information
about arbitrary user X whenever I need it. One way would be to just
print "[[MEMBERINFO:123]]" and then save "123" in an array, fetch
information about all id's in that array and then preg_replace() them
all in the output buffer. But that's not very intelligent either,
since a SQL query with "select x, x, x from member where id in(<list
of 100's of ids>)" isn't very good.
So, basically, I need a function to get information about user X from
a member count of tens of thousands while not being time consuming if
I do it one time on a page or if I do it 100 times on a page.
--
Sandman[.net]
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