Re: transactions from PHP - double COMMIT required?

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2007/3/5, Charley Tiggs <lists@xxxxxxxxx>:
mikie wrote:
> Perhaps I should ask again: is it my responsibility to check if the
> transaction failed and issue a ROLLBACK command, or will the PG server
> do it automatically?

If it were me, I'd assume that responsibility as a matter of course.
Several folks here have given you names of abstraction layers that will
make that simple for you.  By using ADOdb or PearDB or MDB, if the
transaction fails, it will rollback for you.  If you're not going to use
one of those abstraction layers, assume that your request is going to
fail and capture the error and rollback yourself.  At least then, you're
guaranteed a rollback no matter what you pass to the server.

Try this:

In a text file, enter all of your queries.  Start with "BEGIN;" and end
with "COMMIT;".  Be sure to include the error that you mentioned at the
appropriate place.

Login to db using psql command line utility and issue the following command:

\i /path/to/file_with_commands.txt

On my system, when I encounter the error, it does not automatically
issue a rollback.  I have to issue the rollback manually.

I can see the ROLLBACK command displayed and it seems to do it automagically.

However, if I run the file as follows:

psql mydb myusername -f /path/to/file_with_commands.txt

The file will be processed to the end and a rollback will be issued.  At
point of error, I start seeing entries about transaction aborted,
waiting til end of file to rollback.

Here I can see that transaction is aborted and at the end a ROLLBACK
is displayed, so it is also automagically issued

It looks like there is no difference between these two methods that
you suggested.

Anyway I came to the solution like this:
I send pg_query with "BEGIN; insert 1;insert 2; etc...;" -- here there
is no commit nor rollback at the end.
Now I check the result of this pg_query.
If it is OK then I send single query "COMMIT;" and the case is closed
(it means everything went OK).
In case the result of pg_query gives FALSE I send another pg_query "ROLLBACK;".
I checked the logs and the transaction ID is still the same when I
send the other query with "rollback;" or "commit;" after checking the
result.

This seems to be the proper way of handling transaction in PHP without
PDO. It has to be done manually.


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