comp.databases.mysql Google Group

Re: Socket Server with MySQL

jstuck...@attglobal.net (Jerry Stuckle) — Sat, 11 Nov 2009 03:29:52 UT

Yes, they do. But the do not recommend using pools which have
connections which are unused for great lengths of time.

Re: Socket Server with MySQL

a...@vajhoej.dk (Arne Vajhøj) — Sat, 11 Nov 2009 03:01:06 UT

Well - I believe that they do recommend use of connection pools.
Arne

Re: Socket Server with MySQL

jstuck...@attglobal.net (Jerry Stuckle) — Sat, 11 Nov 2009 02:54:15 UT

It is also from the perspective of Oracle, SQL Server and DB2. All of
them recommend AGAINST keeping pools of unused connections open for
extended periods. The needlessly use system resources which could be
used for other things - and can slow down the entire system.
And FYI - MySQL is NOT the first SQL database I ever dealt with. That

Re: Socket Server with MySQL

a...@vajhoej.dk (Arne Vajhøj) — Sat, 11 Nov 2009 02:23:24 UT

This is from the MySQL perspective.
From the application perspective one should close the connection,
but that does release it back to the connection pool - the connection
pool keep the connection open in the database.
Arne

Re: Socket Server with MySQL

jstuck...@attglobal.net (Jerry Stuckle) — Sat, 11 Nov 2009 02:10:32 UT

Not necessarily. It's also a bad idea to leave unused connections open
for hours on Oracle, SQL Server and DB2.
If you're using the connections, there is no problem keeping them open
in MySQL or any other database. But if you're not using the
connections, you should NOT leave them open in any database I'm familiar

Re: Socket Server with MySQL

a...@vajhoej.dk (Arne Vajhøj) — Sat, 11 Nov 2009 02:03:42 UT

That will make the code work well with MySQL but bad with
other databases. If the intent is to write database independent
code, then it is not an optimal solution.
Arne

Re: Socket Server with MySQL

a...@vajhoej.dk (Arne Vajhøj) — Sat, 11 Nov 2009 02:01:27 UT

RVic wrote:
From the practical perspective then I think that:
* if you do not use a connection pool, then you should
send a SELECT 1 every hour to keep things alive
* if you do use a connection pool, then you should
use one capable of verifying connections and return
a valid to you (and if your connection pool does not

Re: Full outer join?

jstuck...@attglobal.net (Jerry Stuckle) — Fri, 11 Nov 2009 22:01:59 UT

Eggzaggly.

Re: Full outer join?

paul_laut...@yahoo.com (Captain Paralytic) — Fri, 11 Nov 2009 21:59:06 UT

On Nov 27, 12:49 pm, "David Portas"
So use UNION ALL

Re: Full outer join?

remove_before_replying_dpor...@acm.org (David Portas) — Fri, 11 Nov 2009 20:49:17 UT

Unfortunately the given workarounds using UNION are not truly FULL OUTER
joins because they eliminate duplicate rows that a real full outer join
would not. In most cases that maybe won't be a problem but I think it's just
worth noting that reproducing the true behaviour of FULL is a bit more
complex than those examples imply.

Re: Complex query on tree structure: Help!

not.h...@localhost (Brian Cryer) — Fri, 11 Nov 2009 16:53:24 UT

This might not count as a single query, but if you know its never more than
5 deep (which you said) then you could do it in 5 queries (one for each
level of depth) and use union to combine the results.

Re: difficult query...for me

jstuck...@attglobal.net (Jerry Stuckle) — Fri, 11 Nov 2009 14:07:05 UT

Still completely unnecessary - and does not create a historical report.

Re: difficult query...for me

jstuck...@attglobal.net (Jerry Stuckle) — Fri, 11 Nov 2009 14:05:40 UT

So a second troll shows up. I respond to trolls in the only language
they understand.

Re: Complex query on tree structure: Help!

t...@invalid.invalid (The Natural Philosopher) — Fri, 11 Nov 2009 11:36:05 UT

Many thanks Andrew, but I already had those!
No, after 4 hours of beating my brains I ended up doing it the long way,
which took ten minutes to code!
I ended up with a two dimensional matrix, and simply walked through that
inserting numbers that are not null, and not already in, into a PHP array.
$result=mysql_query(sprintf(

Re: difficult query...for me

erick.use-...@ardane.c.o.m (Erick T. Barkhuis) — Fri, 11 Nov 2009 08:37:33 UT

Franz:
Still, I wonder if this is really necessary for historical reports,
UNLESS you also remove historical data.
In case you always have the required data in your database, a
historical report could simply be produced using something like
SELECT a,b,c FROM table
WHERE dateA > "2007-01-00" AND dateA < "2008-12-99"