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From:Visolve DB Team Date:December 15 2006 3:51am
Subject:Re: definition of Created_tmp_files in "show status"
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Hi,

Since, these files disappear at the end of the session, for good 
performance, better keep "tmp_table_size" smaller, so we can eliminate 
populating in-memory tables, and make use of disk.  The temporary table size 
is not only determined by tmp_table_size but also by max_heap_table_size

Thanks
ViSolve DB Team.

----- Original Message ----- 
From: "Kevin Fries" <kelfink@stripped>
To: "Visolve DB Team" <mysql_support@stripped>
Cc: <mysql@stripped>
Sent: Thursday, December 14, 2006 9:20 PM
Subject: Re: definition of Created_tmp_files in "show status"


Thanks for that.  Is the only reason for temporary files then going to be 
replication?  And if so, should I be worried that thousands of files have 
been created for this purpose?  Are you saying that I can tune the size (and 
thus the number) of the temp files by adjusting the temporary table size?
My Created_tmp_disk_tables is considerably lower than my Created_tmp_files 
value.  So it seems the Created_tmp_files cannott include the values from 
the Created_tmp_disk_tables.

Kevin

----- Original Message ----
From: Visolve DB Team <mysql_support@stripped>
To: Kevin Fries <kelfink@stripped>; mysql@stripped
Sent: Wednesday, December 13, 2006 9:26:52 PM
Subject: Re: definition of Created_tmp_files in "show status"


Hi,

A replication slave needs some of its temporary files to survive a machine
restart so that it can replicate temporary tables or LOAD DATA INFILE
operations. If files in the temporary file directory are lost when the
server restarts, replication fails. MySQL creates temporary files as hidden
files.

"tmp_table_size" variable will determine the size of the temporary table.
But if it exceeds, then server automatically converts it to disk-based
tables.

The server variables,
Created_tmp_tables -The number of in-memory temporary tables created
automatically by the server while executing statements.
Created_tmp_disk_tables  -The number of temporary tables on disk created
automatically by the server while executing statements.
Created_tmp_files - How many temporary files mysqld has created.
were used to determine the temporary files status.

Thanks
ViSolve DB Team

---- Original Message ----- 
From: "Kevin Fries" <kelfink@stripped>
To: <mysql@stripped>
Sent: Thursday, December 14, 2006 12:57 AM
Subject: definition of Created_tmp_files in "show status"


According to the mysql reference manual, the definition of this field is:
"How many temporary files mysqld has created. "

Can someone elaborate on this?  What causes mysql to create a temporary
file? I see something indicating it may be associated with replication.  In
our environment (which has replication) we see counts for this variable in
the tens of thousands.

Thanks in advance,
Kevin



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Thread
definition of Created_tmp_files in "show status"Kevin Fries13 Dec
  • Re: definition of Created_tmp_files in "show status"Visolve DB Team14 Dec
Re: definition of Created_tmp_files in "show status"Kevin Fries14 Dec
  • Re: definition of Created_tmp_files in "show status"Visolve DB Team15 Dec