I just got a new dual opteron system, with raid 01, 2gb ram, and fedora
core linux running 2.4.22-smp kernel. For some reason mysql is running
pathetically slow. Queries that should take 2ms occasionally take up to
20 seconds. It isn't every time, but almost once per page. The problem
usually occurs with queries accessing the large tables (up to 1gb), but
not always. I've tried 2 versions I compiled myself (with flags
suggested in the readme), as well as the version off the mysql website.
All were 4.0.18, and all had the problem.
Has anyone heard of this problem before, or have any idea why this might
be happening?
Timo
9  1814 
Timo wrote: I just got a new dual opteron system, with raid 01, 2gb ram, and fedora
core linux running 2.4.22-smp kernel. For some reason mysql is running
pathetically slow. Queries that should take 2ms occasionally take up to
20 seconds. It isn't every time, but almost once per page. The problem
usually occurs with queries accessing the large tables (up to 1gb), but
not always. I've tried 2 versions I compiled myself (with flags
suggested in the readme), as well as the version off the mysql website.
All were 4.0.18, and all had the problem.
Without knowing any better, that could be because you are not using
indexing, or queries that you do, don't use indexes. Data can be cached,
or it can randomly be found very quicly, but it also can take very long
time to find it.
Another possibility is that something else is using processor time.
Timo wrote: I just got a new dual opteron system, with raid 01, 2gb ram, and fedora
core linux running 2.4.22-smp kernel. For some reason mysql is running
pathetically slow. Queries that should take 2ms occasionally take up to
20 seconds. It isn't every time, but almost once per page. The problem
usually occurs with queries accessing the large tables (up to 1gb), but
not always. I've tried 2 versions I compiled myself (with flags
suggested in the readme), as well as the version off the mysql website.
All were 4.0.18, and all had the problem.
Without knowing any better, that could be because you are not using
indexing, or queries that you do, don't use indexes. Data can be cached,
or it can randomly be found very quicly, but it also can take very long
time to find it.
Another possibility is that something else is using processor time.
Timo wrote: I just got a new dual opteron system, with raid 01, 2gb ram, and fedora
core linux running 2.4.22-smp kernel. For some reason mysql is running
pathetically slow. Queries that should take 2ms occasionally take up to
20 seconds. It isn't every time, but almost once per page. The problem
usually occurs with queries accessing the large tables (up to 1gb), but
not always. I've tried 2 versions I compiled myself (with flags
suggested in the readme), as well as the version off the mysql website.
All were 4.0.18, and all had the problem.
Without knowing any better, that could be because you are not using
indexing, or queries that you do, don't use indexes. Data can be cached,
or it can randomly be found very quicly, but it also can take very long
time to find it.
Another possibility is that something else is using processor time.
Aggro wrote: Timo wrote:
I just got a new dual opteron system, with raid 01, 2gb ram, and
fedora core linux running 2.4.22-smp kernel. For some reason mysql is
running pathetically slow. Queries that should take 2ms occasionally
take up to 20 seconds. It isn't every time, but almost once per page.
The problem usually occurs with queries accessing the large tables (up
to 1gb), but not always. I've tried 2 versions I compiled myself (with
flags suggested in the readme), as well as the version off the mysql
website. All were 4.0.18, and all had the problem.
Without knowing any better, that could be because you are not using
indexing, or queries that you do, don't use indexes. Data can be cached,
or it can randomly be found very quicly, but it also can take very long
time to find it.
Another possibility is that something else is using processor time.
One query repeated 100 times will take 2 milliseconds probably about 20
times, and 20 seconds about 20 times, the remaining times falling
somewhere in between, usually around the 1-10s range. On my old dual
xeon it never took more than 2ms, even with over a thousand of users
online. This test is with 1 user online. The indexes are setup properly,
so that query only examines about 70 rows of the 70000 rows in that
table. It definately isn't a problem with my queries or table structure.
Top shows NO cpu usage while this query is happening. CHECK says the
tables aren't corrupt or anything like that.
When I moved the database from the old server to the new one, I tarred
the whole directory and untarred it on the new one. It was working
perfectly then, and I haven't been able to find any indication of
corruption. All my CHECKs have passed.
So far my only guesses are that there is some incompatibility between
mysql and fedora (bad library?) or between mysql and my raid controller
driver (I don't know exact specs, but webmin reports: HPT3xx RAID 1/0
Array), or some problem with mysql and opterons. Benchmarks (bonnie++)
show that the harddrives are working at full speed. Fedora only lists a
package for mysql 3.x on the yum list, while I need 4.0.x. I'm not sure
if this is related.
Aggro wrote: Timo wrote:
I just got a new dual opteron system, with raid 01, 2gb ram, and
fedora core linux running 2.4.22-smp kernel. For some reason mysql is
running pathetically slow. Queries that should take 2ms occasionally
take up to 20 seconds. It isn't every time, but almost once per page.
The problem usually occurs with queries accessing the large tables (up
to 1gb), but not always. I've tried 2 versions I compiled myself (with
flags suggested in the readme), as well as the version off the mysql
website. All were 4.0.18, and all had the problem.
Without knowing any better, that could be because you are not using
indexing, or queries that you do, don't use indexes. Data can be cached,
or it can randomly be found very quicly, but it also can take very long
time to find it.
Another possibility is that something else is using processor time.
One query repeated 100 times will take 2 milliseconds probably about 20
times, and 20 seconds about 20 times, the remaining times falling
somewhere in between, usually around the 1-10s range. On my old dual
xeon it never took more than 2ms, even with over a thousand of users
online. This test is with 1 user online. The indexes are setup properly,
so that query only examines about 70 rows of the 70000 rows in that
table. It definately isn't a problem with my queries or table structure.
Top shows NO cpu usage while this query is happening. CHECK says the
tables aren't corrupt or anything like that.
When I moved the database from the old server to the new one, I tarred
the whole directory and untarred it on the new one. It was working
perfectly then, and I haven't been able to find any indication of
corruption. All my CHECKs have passed.
So far my only guesses are that there is some incompatibility between
mysql and fedora (bad library?) or between mysql and my raid controller
driver (I don't know exact specs, but webmin reports: HPT3xx RAID 1/0
Array), or some problem with mysql and opterons. Benchmarks (bonnie++)
show that the harddrives are working at full speed. Fedora only lists a
package for mysql 3.x on the yum list, while I need 4.0.x. I'm not sure
if this is related.
Aggro wrote: Timo wrote:
I just got a new dual opteron system, with raid 01, 2gb ram, and
fedora core linux running 2.4.22-smp kernel. For some reason mysql is
running pathetically slow. Queries that should take 2ms occasionally
take up to 20 seconds. It isn't every time, but almost once per page.
The problem usually occurs with queries accessing the large tables (up
to 1gb), but not always. I've tried 2 versions I compiled myself (with
flags suggested in the readme), as well as the version off the mysql
website. All were 4.0.18, and all had the problem.
Without knowing any better, that could be because you are not using
indexing, or queries that you do, don't use indexes. Data can be cached,
or it can randomly be found very quicly, but it also can take very long
time to find it.
Another possibility is that something else is using processor time.
One query repeated 100 times will take 2 milliseconds probably about 20
times, and 20 seconds about 20 times, the remaining times falling
somewhere in between, usually around the 1-10s range. On my old dual
xeon it never took more than 2ms, even with over a thousand of users
online. This test is with 1 user online. The indexes are setup properly,
so that query only examines about 70 rows of the 70000 rows in that
table. It definately isn't a problem with my queries or table structure.
Top shows NO cpu usage while this query is happening. CHECK says the
tables aren't corrupt or anything like that.
When I moved the database from the old server to the new one, I tarred
the whole directory and untarred it on the new one. It was working
perfectly then, and I haven't been able to find any indication of
corruption. All my CHECKs have passed.
So far my only guesses are that there is some incompatibility between
mysql and fedora (bad library?) or between mysql and my raid controller
driver (I don't know exact specs, but webmin reports: HPT3xx RAID 1/0
Array), or some problem with mysql and opterons. Benchmarks (bonnie++)
show that the harddrives are working at full speed. Fedora only lists a
package for mysql 3.x on the yum list, while I need 4.0.x. I'm not sure
if this is related.
Timo wrote: So far my only guesses are that there is some incompatibility between
mysql and fedora (bad library?) or between mysql and my raid controller
driver (I don't know exact specs, but webmin reports: HPT3xx RAID 1/0
Array), or some problem with mysql and opterons. Benchmarks (bonnie++)
show that the harddrives are working at full speed. Fedora only lists a
package for mysql 3.x on the yum list, while I need 4.0.x. I'm not sure
if this is related.
I have no clue what it could be then. But you could try is it slow even
with only 200 rows or something like that, if it possible to create test
table for this purpose.
If it is slow even with that row amount, then it surely isn't about
indexes or anything similar.
Timo wrote: So far my only guesses are that there is some incompatibility between
mysql and fedora (bad library?) or between mysql and my raid controller
driver (I don't know exact specs, but webmin reports: HPT3xx RAID 1/0
Array), or some problem with mysql and opterons. Benchmarks (bonnie++)
show that the harddrives are working at full speed. Fedora only lists a
package for mysql 3.x on the yum list, while I need 4.0.x. I'm not sure
if this is related.
I have no clue what it could be then. But you could try is it slow even
with only 200 rows or something like that, if it possible to create test
table for this purpose.
If it is slow even with that row amount, then it surely isn't about
indexes or anything similar.
Timo wrote: So far my only guesses are that there is some incompatibility between
mysql and fedora (bad library?) or between mysql and my raid controller
driver (I don't know exact specs, but webmin reports: HPT3xx RAID 1/0
Array), or some problem with mysql and opterons. Benchmarks (bonnie++)
show that the harddrives are working at full speed. Fedora only lists a
package for mysql 3.x on the yum list, while I need 4.0.x. I'm not sure
if this is related.
I have no clue what it could be then. But you could try is it slow even
with only 200 rows or something like that, if it possible to create test
table for this purpose.
If it is slow even with that row amount, then it surely isn't about
indexes or anything similar. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
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