May i barge into this discussion a bit.... and please, feel free to shut
me down if i'm missing a point here.
I'm failing to see why all this debate. We already have transactions, we
have begin, commit and rollback in the abstraction (Database.php lines
2830+). And this works. All that needs to be done is extending this
functonality without breaking the existing MO which maintains a single
transaction level.
Daniel, you have the same issue as Akshay has in his extension, which is
the fact that doEdit closes a transation before you complete the whole
editing process. So you don't need nested transactions as such ... just
a way to prevent core from commiting if your extension spans over
multiple core transactions and taking over the commiting/rollingback by
yourself ... basically what you need is this (not sure about PG
compatibility here):
public function begin( $fname = 'DatabaseBase::begin', $maskTransaction ) {
if ( $this->mTrxLevel < 2 ) {
$this->query( 'BEGIN', $fname );
$this->mTrxLevel = 1;
// this is here just to make sure that begin works the same way
as now when on txLevel = 1
if ( $maskTransaction ) {
$this->mTrxLevel++;
}
} else {
$this->mTrxLevel++;
$this->query( 'SAVEPOINT SP'.$this->mTrxLevel, $fname );
}
}
public function commit( $fname = 'DatabaseBase::commit', $doGlobally = false ) {
if ( $this->mTrxLevel == 1 || $this->mTrxLevel == 2 || $doGlobally ) {
$this->query( 'COMMIT', $fname );
$this->mTrxLevel = 0;
} else {
$this->mTrxLevel--;
}
}
public function rollback( $fname = 'DatabaseBase::rollback', $doGlobally =
false ) {
if ( $this->mTrxLevel == 1|| $this->mTrxLevel == 2 || $doGlobally ) {
$this->query( 'ROLLBACK', $fname, true );
$this->mTrxLevel = 0;
} elseif ( $this->txLevel > 0 ) {
$this->query( 'ROLLBACK TO SAVEPOINT SP'.$this->mTrxLevel,
$fname, true );
$this->mTrxLevel--;
}
}
This should not change anything in core, and an extension gets a way to
block core's commits and restarts of an already open transaction. I've
added the savepoints-foo, just to have a complete solution.
So what's so drastic about such change? Why all this debate?
On 08/28/2012 09:16 AM, Daniel Kinzler wrote:
On 28.08.2012 06:16, Aaron Schulz wrote:
I'd have to see what you are doing to see if rollback is really needed.
As far as I see, nested transactions are needed, but no rollback. at least not
from our side.
So, for that case, a simple counter would be sufficient. I still wonder why that
feature got removed from the code.
-- daniel
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