Re: Statement handle still Active: prepare_cached
- From: nomad@xxxxxxxx (Mark Lawrence)
- Date: Wed, 26 Mar 2008 00:12:09 +0100
On Tue Mar 25, 2008 at 10:35:39AM +0000, Tim Bunce wrote:
On Tue, Mar 25, 2008 at 09:31:30AM +0100, Mark Lawrence wrote:
I'm having a problem with one of my modules (SQL::DB) failing on
calls to prepare_cached. I'm asking here for help because this is
failing on every CPAN Tester's build, but I can't repeat the issue
locally (x86_64 Debian). The tests use SQLite for the database.
The error is occuring on INSERT and UPDATE statements:
t/09-db...........prepare_cached(INSERT INTO
sqldb (name, val)
VALUES
(?, ?)
) statement handle DBI::st=HASH(0xdf1cd8) still Active at ...
As far as I know I am not nesting calls to the same statement. But even
if I was, what I don't understand is how an INSERT or UPDATE statement
handle remains active after the database call. According to the pod:
"Active" (boolean, read-only)
The "Active" attribute is true if the handle object is "active". This
is rarely used in applications. The exact meaning of active is somewhat
vague at the moment. For a database handle it typically means that the
handle is connected to a database ("$dbh->disconnect" sets "Active"
off). For a statement handle it typically means that the handle is a
"SELECT" that may have more data to fetch. (Fetching all the data or
calling "$sth->finish" sets "Active" off.)
I know about the $if_active option to prepare_cached, but I would rather
get the warnings and I don't want new statement handles added to the
cache for what I believe is the same statement.
You're right that INSERT or UPDATE statements shouldn't have Active set.
I'd start by trying to understand how/why/where that's happening.
I have found out two bits of information which may be related:
1. I have been using a prepare_cached / bind_param / execute cycle on
INSERT / UPDATE / DELETE methods instead of do(), because I need to set
the parameter bind type - at least on INSERT / UPDATE. I suspect that the
$sth->execute() call is not finish()ing off the statement handle.
Perhaps because it assumes execute() is a SELECT call? I haven't looked
at the code to confirm this...
2. I was also assuming that the fetchrow_array/ref methods would know if
they had retrieved the last row, but that doesn't seem to be the case
until they actually try to fetch that non-existent row. So statements
with "LIMIT 1" followed by a fetchrow_array are not yet finished - you
have to make another fetchrow_array call or finish() the statement
handle manually.
At least I wasn't making recursive queries.
I have other question: The call to prepare_cached is happening
inside two eval{} blocks, yet the error message above doesn't come from
my code but instead from DBI.
I'm not quite sure what you're saying here, but the warning is generated
by prepare_cached() in DBI.pm using carp().
Perhaps it is the Test::More infrastructure which is forcing the
warnings somehow.
Anyhow, version 0.12 is now on CPAN. Time to wait and see. Gotta love
those testers.
Mark.
--
Mark Lawrence
.
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- Statement handle still Active: prepare_cached
- From: Mark Lawrence
- Re: Statement handle still Active: prepare_cached
- From: Tim Bunce
- Statement handle still Active: prepare_cached
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