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From:Dan Nelson Date:January 24 2004 7:56pm
Subject:Re: Reducing MySQL memory consumption?
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In the last episode (Jan 24), Philip Mak said:
> My machine appears to be swapping excessively, degrading performance.
> Note the high load average, combined with the mostly idle CPU and a
> lot of swap space being used.

You didn't say what OS you're using, but the below top output looks
like Linux's procps top, which doesn't tell you your paging rate.  Run
"vmstat 1" and watch the si and so columns.  Just because swap is being
used doesn't mean you're thrashing.  You need to know the rate.
>   3:11am  up 47 days,  2:13, 12 users,  load average: 6.06, 4.79, 3.19
> 482 processes: 480 sleeping, 1 running, 1 zombie, 0 stopped
> CPU states:  1.7% user,  3.5% system,  0.0% nice, 94.6% idle
> Mem:  1031204K av, 1010340K used,   20864K free,       0K shrd,   76084K buff
> Swap: 1020116K av,  397720K used,  622396K free                  424652K cached
> I looked at "top" sorted by memory usage, and saw dozens of mysqld
> processes at the top (each with size 35492, RSS 23M, share 1240). So
> it appears that mysqld is taking up a lot of memory.

No, mysql is taking up 23MB.  Linux creates separate processes for each
thread, which is why you see lots of mysqlds in top.  They all share
the same address space, though.  Are you sure you don't maybe have a
couple dozen apache processes consuming your memory instead?

	Dan Nelson
Reducing MySQL memory consumption?Philip Mak24 Jan
  • Re: Reducing MySQL memory consumption?Dan Nelson24 Jan
    • Re: Reducing MySQL memory consumption?Philip Mak28 Jan
      • Re: Reducing MySQL memory consumption?Dan Nelson28 Jan