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From:Duhaime Johanne Date:April 19 2005 2:25pm
Subject:Second call: How many innodb_log_file and how many groups
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Hello

I have sent this e-mail 2 weeks ago and did not get any answers. Please
allow me to give a second try.

I have Mysql 4.1.7 on Solaris / innodb tables
I have 2 innodb_log_files of 100M each. A group of statements (19000
insert) does that both logfiles are stamped with the same time. It might
be because one has just finished filled and the other start or it might
be because they both rotated and my data might be lost in a crash. To
prevent that, I could increase the files size but they are already big
enough and the recovery might take too long as it is said in the
documentation.

What I want to do, is to create 4 files of 50M instead of 2 files of
100M. In the documentation it is said that the number of files
"recommended" is 2. Is there a problem to have more? Just to confirm
that the "recommended" applies to "have more than one". Does more files
decrease the speed?

Second. Since there is a parameter "innodb_log_files_in_group" does it
means that I can have more than one group? If so, is the group concept
for duplicates of innodb_log_files that you would be kept on another
diks to reinforce the safety of the data?

And finally, if you are still there:

The innodb_buffer_log_buffer_pool_size should be +~80% of the memory
available. I have 4 gigs. Let's I fixed it at 3 gigs.
Now the innodb_log_files_size: "sensible values range" from 1MB to 1/n
of the size of the buffer pool (N =3D number of logs size)
If I use 2 logfiles I get 1.5 gigs.
if I use 4 logfiles I get 750 megs
Is not that too big for the recovery.

Thank you in advance

Johanne Duhaime


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Second call: How many innodb_log_file and how many groupsDuhaime Johanne19 Apr