Subject Re: [Firebird-Java] reuse of connection after failure.
Author Andrew Goedhart

It was tongue in cheek comment. (Well maybe a little bit of concern:-)

Seeing the effort you have gone to to help it is only fair to return something in exchange, so yes once the dust has settled on what we are trying to do, I will be willing to write up a 'success' story/ case study for the web site.

Btw Currently I expect us to reach about 600GB-1TB by the end of the year, with peak load of about 250 000+ transactions per hour, and replicated and distributed database configurations, So it will definitely make a good small to medium size enterprise case study.

So far so good with the patch.


----- Original Message -----
From: Roman Rokytskyy <rrokytskyy@...>
Sent: Tuesday, March 13, 2007 8:59:06 PM GMT+0200 Africa/Harare
Subject: Re: [Firebird-Java] reuse of connection after failure.

> The sound of surprise in David's voice that someone was actually using the Firebird XA leaves me with a tingling sensation all over. And here I was suckered by the marketing, believing I was one of the millions world wide who where using Firebird everyday in their data centres. Gee there's one born every minute, just why does it have to be me ;-)

Let's do some guesswork (risking Helen killing me instantly for making
wrong guesses).

If you check the download statistics of Jaybird, you will see that we
have something like 10,000 users. The question is how many of them are
running system in production. At my work (I'm IT consultant in Germany,
involved mainly in banking sector) the more or less standard environment
is JDK 1.4 (rarely 1.3) and very rarely JDK 5.0.

The Jaybird 2.0.1 for JDK 1.4 was downloaded ~5,700 times. Let's assume
that it was downloaded by each developer in a team separately. Assuming
the team size of 10 developers on average we have about 500 production
systems (note, we're talking about systems in general, I know of one
installation running Firebird and Jaybird that is installed in many
Russian cities, though on our download page we would all of them as one
hit, since the developers distribute the final system themselves).

I see following deployment modes:

- plain J2EE stack without EJBs (i.e. Tomcat->JDBC->FB or
- plain EJB with entity beans;
- EJB + O/R mapping;

First case is not interesting to us, since they use plain vanilla JDBC.
I would estimate such applications to have about 40%. That leaves us 300
production systems running EJB. From those I would say 80% use JBoss and
Firebird (240 systems). They can be further splitted into two
categories: those that use XA and those that don't. The ratio, I'd say
is 20:80 in ideal case, but since developers are lazy and default
configuration with JBoss is XA-enabled, I correct it to be 40:60.

This gives us about 100 production systems running EJB-stack accessing
FB in XA-mode. You happen to be the one from those 100 systems that
experience regular FB crashes due to a huge DB size (those 180 GB is not
yet common in FB world) who did not accepted EJB-server restart as an
option to cope with the FB crash.

I'd say this is quite realistic estimation.

So, the answer to your original question is: no, you're not the only one
using XA-mode. BTW, there is another 100 or more installations of
Jaybird with JBoss in production - the Fyracle/Compiere ERP systems.
Those have their own installer that distributes Jaybird bundled. However
you're quite unique considering the load you're producing - comparable
systems running Firebird, AFAIK, do not run Java - majority comes from
Delphi world.

BTW, would you be interested in making a "success story" for Firebird