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From:Michael Widenius Date:April 1 1999 12:28pm
Subject:How does it work
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>>>>> "list" == list  <list@stripped> writes:

list> I have quite some experience with Mysql,perl and DBI, but would
list> like to know a bit more. Could somebody explain these tow
list> questions?  Please? :)

list> 1)

list> As I undestand it, the database handle as obtained by
list> DBI->connect might go stale and disappear when it actually still
list> is in use.  Is there any way to keep it up, or do I have to do a
list> ping to the $dbh for every $sth I use?

This should only happen if the connect has been idle for more than 8
hours or if the MySQL server has been restarted.  In most cases, the
connect code will automaticly reconnect in this case.
There is also a 'ping' DBI method you can use;  If you have some point 
in your code where the client may sleep for hours, it's probably a
good idea to issue a 'ping' after it has waken up.

list> 2)

list> I assume the database handle is not unique but shared amongst
list> all the programs using the same database, and the statement
list> handles are unique and recreated even if the query and database
list> are exactly the same. Is this true?

Yes (as long as you don't use threads)

list> And, if I'm correct, does this mean it is wise to create new
list> statements for queries done in parallel but I can keep ony
list> database handle.  Is this valid for forked process also, or do I
list> get a copy of the statement handle and thus am not required to
list> create a new statement, it would even be unwise because it uses
list> more memory?

If you fork, you have to use a different connection for each child.
You should first fork and after this open an own connection in each
child.

Regards,
Monty
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How does it worklist1 Apr
  • How does it workMichael Widenius1 Apr