Re: [Dbi-interbase-devel] Deadlocks galore

[Mark D. A. <md...@di...>]

> Commit-retaining should IMHO only be used in autocommit mode (it only
> matters in autocommit mode as commits are more infrequent in normal mode, 
> so the performance hit from starting a new transcation is much smaller)

i don't think commit_retaining should be the default behavior in either mode,
as i think i've ranted about previously in this forum :).
it has a very specialized use, when there is only a single writer for a table.
it should be an optional behavior, set at create time or commit time.

> 
> Not having an active transcation after a commit is important, or you will
> have active transactions across requests (this may be a very long
> time) and a newly started reuest will be working with a really
> (really) old snapshot in stead of a new one.

with commit_retaining, it'll be an old snapshot regardless.

> 
> I would suggest that:
> * commit_retaining should only be used for autocommit after queries.

i disagree on this one. based on using other transaction parameters, there are other ways of improving
the performance of these, without the usually disastrous semantics of commit_retaining.

> * Explicit commits/rollbacks always commit_transcation /
> rollback_transaction and then end the transaction, completely.
> * any operation that needs a query should check to see if one is active
> and start one if not.

the above is how the new dbd driver works in autocommit mode, but not how
it used to work, and it was definitely a problem. i haven't ranted as much about
non-autocommit because i'm not using it that way.

> I don't know if these changes would fix my immediate problem, but they are
> correct and I expect they will fix my problem.

i've been having a variety of problems with my apache/modperl/dbi system, and
not using the old driver (which had a variety of problems, some in dbd and some
in ibperl) has now allowed me to pay attention to some database server-side problems.

are you using SS or classic? on linux? local or remote mode?
it'd be nice to know there is someone else doing the same thing architecture as me -- most
of the discussion on the support lists is concerning all these moribund borland
fabrications like ibx/delphi/etc.

-mda