On Nov 28, 2006, at 3:04 PM, Robert Landrum wrote:
Lev Lvovsky wrote:
In testing out persistent connections while using transactions,
we've noticed that while in a loop which continuously begins and
ends a transaction, killing the persistent connection which
Apache::DBI is maintaining causes the still-running handler to
report things like:
error: DBD driver has not implemented the AutoCommit attribute
at /usr/lib/perl5/vendor_perl/5.8.8/i386-linux-thread-multi/
DBI.pm line 1668.
1 -> STORE for DBD::mysql::db (DBI::db=HASH(0x9bf49cc)~INNER
'AutoCommit' 0) thr#915dc30
--> do_error
Turning off AutoCommit failed error 21 recorded: Turning off
AutoCommit failed
<-- do_error
STORE DBI::db=HASH(0x9bf49cc) 'AutoCommit' => 0
!! ERROR: 21 CLEARED by call to begin_work method
-> begin_work for DBD::mysql::db (DBI::db=HASH(0x9b8678c)
~0x9bf49cc) thr#915dc30
So, your code is calling begin_work, fetching a value, storing a
value, and committing? The store will fail if the database
connection goes away, and it'll do so when it attempts communicate
with the server to set AutoCommit to 0.
You might want to call $dbh->ping before calling your store
routine. Either way, the way to make this fault tolerant is with eval.
Once you've determined that there's been a fault, and that the
fault means that the database is down, try to reconnect. Continue
to try to reconnect until the database comes back online. Then
retry the original failed transaction.
Once you reconnect, the connection is persistent again. At least,
that's been my experience with postgresql.
This is exactly what I've been thinking to do, but I've not seen
anything within Apache::DBI that allows me to reconnect per se. How
do I perform that action?
Also, forgive this question if it seems a little obtuse, but in the
startup.pl file, I do something like this:
Apache::DBI->connect_on_init(...)
how do I then get the database handle that this establishes, so that
I can pass it around to the mod_perl hanlders, and the subsequent DBI
stuff? get_handlers() from the Apache2::ServerUtil class?
thanks very much!
-lev
