Jon,
using a > 4 GB buffer pool is safe in a 64-bit computer, and allocating
50 % - 80 % of memory to the buffer pool is recommended in an
InnoDB-only server.
Regards,
Heikki
Oracle/Innobase
----- Alkuperäinen viesti -----
Lähettäjä: "Jon Frisby" <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>
Vastaanottaja: "Heikki Tuuri" <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>; <mysql@lists.mysql.com
<mailto:mysql@lists.mysql.com>>
Lähetetty: Tuesday, October 18, 2005 4:39 AM
Aihe: RE: Non-linear degradation in bulk loads?
Side question: If I use a 64-bit MySQL build on a 64-bit kernel, is it
safe and sane to allocate say, 6GB to the InnoDB buffer pool?
On an 8GB box, 64-bit software stack, what is the optimum memory
allocation for a pure-InnoDB (* - MyISAM used only for grant tables)
mysql server running as the sole application on the machine?
-JF
> -----Original Message-----
> From: Heikki Tuuri [mailto:[EMAIL PROTECTED]
> Sent: Monday, October 17, 2005 10:55 AM
> To: mysql@lists.mysql.com <mailto:mysql@lists.mysql.com>
> Subject: Re: Non-linear degradation in bulk loads?
>
> Jon,
>
> I am not 100 % sure that the problem we saw was in a 64-bit
> Linux. It might have been 32-bit.
>
> Anyway, since CentOS is a clone of RHEL, this might be the
> same file cache phenomenon. I do not know if one can force
> the file cache to stay smaller than 4 GB. You can try running
> some dummy programs that occupy a few GB of memory.
>
> Regards,
>
> Heikki
> Oracle/Innobase
>
> ----- Alkuperäinen viesti -----
> Lähettäjä: "Jon Frisby" <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>
> Vastaanottaja: "Heikki Tuuri" <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>;
> <mysql@lists.mysql.com <mailto:mysql@lists.mysql.com>>
> Lähetetty: Monday, October 17, 2005 8:49 PM
> Aihe: RE: Non-linear degradation in bulk loads?
>
>
> Sorry to spam the group, but I just noticed that I asserted
> we were on a
> 2.4 kernel -- we're on 2.6.9-11 as part of CentOS 4.1...
>
> -JF
>
>
> > -----Original Message-----
> > From: Heikki Tuuri [mailto:[EMAIL PROTECTED]
> > Sent: Sunday, October 16, 2005 2:23 AM
> > To: mysql@lists.mysql.com <mailto:mysql@lists.mysql.com>
> > Subject: Re: Non-linear degradation in bulk loads?
> >
> > Jon,
> >
> > your hardware/OS combination is quite new and unusual. It
> might indeed
> > be an OS problem. We observed from a 64-bit RHEL
> > 4 that when the file cache of the OS grew bigger than 4 GB,
> then the
> > file I/O performance dropped to one tenth of the normal.
> You would not
> > expect that kind of behavior from a 64-bit OS.
> >
> > When you see the slowdown, what does 'top' say about the OS
> file cache
> > size?
> >
> > "
> > The database is our main sites database but we've
> dramatically reduced
> > the load on that machine over the past couple months
> through careful
> > optimization of our code. The box is a dual, dual-core
> Opteron, 8GB
> > of RAM running a 32-bit Linux 2.4 kernel and MySQL 4.0.20
> (32-bit of
> > course). We have 1GB allocated to the buffer pool, and our
> usual 1GB
> > *
> > 3 log files. 8 I/O threads.
> >
> > Load on the box sits at around 6-7, with a large (>50%)
> amount of time
> > spent in wait state, but actual disk throughput to our
> software RAID
> > array (No longer on a SAN...) is quite low -- 6-9k blocks/s
> out, 1-6k
> > blocks/s in.
> > "
> >
> > Regards,
> >
> > Heikki
> >
> >
> > ----- Original Message -----
> > From: ""Jon Frisby"" <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>>
> > Newsgroups: mailing.database.myodbc
> > Sent: Friday, October 14, 2005 10:39 PM
> > Subject: RE: Non-linear degradation in bulk loads?
> >
> >
> > > I've tried tweaking the structure of the schema to have,
> > for example, a =
> > > PRIMARY KEY index on email, no other indexes, and then
> > insert in sorted =
> > > order -- made no improvement whatsoever. Another clue that
> > leads me to =
> > > believe that this may be an OS issue: Starting a large cp
> > on the same =
> > > box (from a local filesystem other than the one the InnoDB
> > data pool was =
> > > on, to NFS) caused MySQL to become COMPLETELY backlogged
> > (we went from =
> > > ~15-20 connections at any given instant to 750 (our
> > max_connections =
> > > setting)).
> > >
> > > -JF
> > >
> > >
> > >> -----Original Message-----
> > >> From: Heikki Tuuri [mailto:[EMAIL PROTECTED]
> > >> Sent: Wednesday, October 12, 2005 8:15 AM
> > >> To: mysql@lists.mysql.com <mailto:mysql@lists.mysql.com>
> > >> Subject: Re: Non-linear degradation in bulk loads?
> > >>=20
> > >> Jon,
> > >>=20
> > >> hmm... maybe one of the indexes inevitably is in a random order.
> > >>=20
> > >> Please post a typical
> > >>=20
> > >> SHOW INNODB STATUS\G
> > >>=20
> > >> when the inserts happen slowly.
> > >>=20
> > >> What is your my.cnf like?
> > >>=20
> > >> Regards,
> > >>=20
> > >> Heikki
> > >> Innobase/Oracle
> > >>=20
> > >> ----- Alkuper=E4inen viesti -----
> > >> L=E4hett=E4j=E4: "Jon Frisby" <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>>
> > >> Vastaanottaja: "Heikki Tuuri" <[EMAIL PROTECTED]>;=20
<mailto:[EMAIL PROTECTED];=20>
> > >><mysql@lists.mysql.com <mailto:mysql@lists.mysql.com>>
> > >> L=E4hetetty: Wednesday, October 12, 2005 3:08 AM
> > >> Aihe: RE: Non-linear degradation in bulk loads?
> > >>=20
> > >>=20
> > >> > Two solutions: 1) sort the rows to be inserted on the
> > key 'email'=20
> > >> > before inserting.
> > >> >
> > >> > 2) Or:
> > >> >
> > >> > http://dev.mysql.com/doc/mysql/en/innodb-tuning.html
> > >> > "
> > >> > If you have UNIQUE constraints on secondary keys, starting=20
> > >> from MySQL
> > >> > 3.23.52 and 4.0.3, you can speed up table imports by
> > temporarily=20
> > >> > turning off the uniqueness checks during the import session:
> > >> > SET UNIQUE_CHECKS=3D0;
> > >> >
> > >> > For big tables, this saves a lot of disk I/O because
> > InnoDB can use=20
> > >> > its insert buffer to write secondary index records in a batch.
> > >> > "
> > >> >
> > >> > But make sure you do not have any duplicates in the rows!
> > >>=20
> > >> After sending my mail, I discovered SET
> UNIQUE_CHECKS=3D0, and=20
> > >>subsequent to that it also occurred to me to try putting the=20
> > >>data in in sorted order. Unfortunately, doing=20
> UNIQUE_CHECKS=3D0
> > >>did not work, and even the combination of=20 both did not work.
> > >>First chunk (3.4m rows) was ~1.5 minutes,=20 second was ~5
> > >>minutes...
> > >>=20
> > >> At this point I'm inclined to believe that there is
> something=20
> > >>very wrong with the disk subsystem because of this and other=20
> > >>problems (doing a large cp from the datapool filesystem to=20
> > >>another filesystem brought the database to a near-halt, among=20
> > >>other things).
> > >>=20
> > >> As a stop-gap solution, I created the table with no indexes,=20
> > >>and loaded all the data (loaded in linear time), and plan on=20
> > >>doing a CREATE UNIQUE INDEX on the table. Will this
> happen=20 in
> > >>linear time, or near-linear time?
> > >>=20
> > >> *sigh*
> > >>=20
> > >> -JF=20
> > >>=20
> > >>=20
> > >> --
> > >> MySQL General Mailing List
> > >> For list archives: http://lists.mysql.com/mysql
> > >> To unsubscribe: =20
> > >> http://lists.mysql.com/[EMAIL PROTECTED]
> > >>=20
> > >>=20
> > >
> > > --
> > > MySQL General Mailing List
> > > For list archives: http://lists.mysql.com/mysql To unsubscribe:
> > >
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> > >
> >
> >
> > --
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> >
> >
>
>
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