Re: [GENERAL] big bad join problems

Bruce Momjian wrote:

On Mon, 1 Feb 1999, Bruce Momjian wrote:

Actually, it's still fairly slow. I've got two things that my
view is pulling back now, and it's taking quite a while. I'm going to
load up a bunch of data and see if it gets any slower. Is there an actual
problem happening here?

With the GEQO problems people were having, I have modified the default
GEQO start table count from 8 to 6.

People are having trouble at values of > 6 for a while, but
someone(Vadim?) objected to setting it to six in the past. With two
people having problems today, I wanted to lower it.

Yes, it was me. I don't object against 6, but just remember that
there were other people having troubles with GEQO and this is
why table count was increased from 6 to 8.

Vadim

Bruce Momjian wrote:

On Mon, 1 Feb 1999, Bruce Momjian wrote:

Actually, it's still fairly slow. I've got two things that my
view is pulling back now, and it's taking quite a while. I'm going to
load up a bunch of data and see if it gets any slower. Is there an actual
problem happening here?

With the GEQO problems people were having, I have modified the default
GEQO start table count from 8 to 6.

People are having trouble at values of > 6 for a while, but
someone(Vadim?) objected to setting it to six in the past. With two
people having problems today, I wanted to lower it.

Yes, it was me. I don't object against 6, but just remember that
there were other people having troubles with GEQO and this is
why table count was increased from 6 to 8.

Do you remember what problems?

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Bruce Momjian wrote:

Bruce Momjian wrote:

On Mon, 1 Feb 1999, Bruce Momjian wrote:

Actually, it's still fairly slow. I've got two things that my
view is pulling back now, and it's taking quite a while. I'm going to
load up a bunch of data and see if it gets any slower. Is there an actual
problem happening here?

With the GEQO problems people were having, I have modified the default
GEQO start table count from 8 to 6.

People are having trouble at values of > 6 for a while, but
someone(Vadim?) objected to setting it to six in the past. With two
people having problems today, I wanted to lower it.

Yes, it was me. I don't object against 6, but just remember that
there were other people having troubles with GEQO and this is
why table count was increased from 6 to 8.

Do you remember what problems?

No. Either the same as now (long planning) or bad plans
(long execution).

Vadim

On Tue, 2 Feb 1999, Vadim Mikheev wrote:

# > Do you remember what problems?
#
# No. Either the same as now (long planning) or bad plans (long
# execution).

I don't have enough data to know whether it's planning well or
not, but I can't do two queries at the same time for lack of RAM with
GEQO, and the web browser times out without it. :) I'm torn. If only I
could store a query plan. (subliminal message)

--
SA, beyond.com My girlfriend asked me which one I like better.
pub 1024/3CAE01D5 1994/11/03 Dustin Sallings <dustin@spy.net>
| Key fingerprint = 87 02 57 08 02 D0 DA D6 C8 0F 3E 65 51 98 D8 BE
L_______________________ I hope the answer won't upset her. ____________

Yes, it was me. I don't object against 6, but just remember that
there were other people having troubles with GEQO and this is
why table count was increased from 6 to 8.

Do you remember what problems?

No. Either the same as now (long planning) or bad plans
(long execution).

My rememberance was that GEQO was slower for some 6-table joins, so it
was recommended to keep it at 8. Tom clearly is on the proper track in
checking the number of indexes when using GEQO. That should allow us to
set a proper value that will use GEQO in most/all cases.

-- 
  Bruce Momjian                        |  http://www.op.net/~candle
  maillist@candle.pha.pa.us            |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026