Hi
The only thing I can say is that if you optimise the table often there is
less work for it to do so you table will be left locked for shorter time.
I have not looked in to this but if you use the RAID option. I don't know if
splitting the table up you could just work on one bit at a time??????

Simon

-----Original Message-----
From: Alexander Schulz [mailto:[EMAIL PROTECTED]
Sent: 15 July 2003 13:35
To: [EMAIL PROTECTED]; [EMAIL PROTECTED]
Subject: Managing big tables


Hello,
i've got a little problem,
we're using mysql with two big tables (one has 90 Mio. Rows (60 Gb on 
HD), the other contains nearly 200.000.000 (130 Gb on HD).
Now we want to delete some rows from these tables to free diskspace. It 
seems that MySQL frees the harddisk-space which
was used by these rows only after optimization, which lasts very long on 
these tables. Both tables are "dynamic" in terms of row-format
what seems to extend the time needed for optimization. I tried to 
convert the smaller one to "fixed"-row-format, which increased the
disk-space of its data-file from 30 Gb to 60 Gb. This would not be the 
problem, but some SQLs which are run daily
on this table now run 4 times slower than with dynamic structure.

So, my questions are:
1) Did i something wrong while converting to fixed row-format ? (i found 
no indication)
2) Is the fixed structure really faster on optimization ?
3) Can anybody confirm the slow-down on big tables when converted from 
dynamic to fixed ?
    (on small tables fixed were faster)

I'm running SuSE Linux, Kernel 2.4.20, the above behaviour could be 
reproduced with our productive server (MySQL 3.23) and
with a test server (MySQL 4.0.12).

thanks in advance,
alex



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