[erlang-questions] MySQL driver

Henning Diedrich <>
Thu Apr 11 00:41:26 CEST 2013


Hi Garrett,

great, I'll check out your connection time outs, thanks a lot!

It was quite fun to find Jacob, Nick and Fredrik to write this [1] up. It certainly felt more like historical forensics from some point on although I was throughout only trying to find out which driver version made most sense. Which in the end came to light in a way I could not read out of the source.

If someone would like to share the story of his fork I'll be happy to include it, for the fun of it. Somehow, this all fits MySQL.

Henning 

[1] https://github.com/eonblast/Emysql#History


On Apr 11, 2013, at 12:25 AM, Garrett Smith <> wrote:

> Someday someone will write a book on the history of the Erlang MySQL
> libraries. Not a great read, but it'd have to be scholarly.
> 
> I've modified the Eonblast library with some connection timeout tweaks
> (as in, supporting them):
> 
> https://github.com/gar1t/Emysql
> 
> 
> 
> On Wed, Apr 10, 2013 at 4:59 PM, Dave Smith <> wrote:
>> Hi Henning,
>> 
>> Thanks for the pointers. I must admit that I find the level of snark in the
>> emysql history delightful, considering that it's at least as forked as
>> erlang-mysql-driver now. :)
>> 
>> There are a number of good fixes for the emysql driver, but they are on 20
>> different forks across Github. Looking over csrl's, fixes, I'm pretty
>> concerned those aren't in mainline since there are some non-trivial pooling
>> problems he's addressed (would you like some irony with that irony? :)).
>> 
>> Do you know if eonblast is planning to incorporate all the work from those
>> different forks? I think we need to build some momentum behind a driver and
>> I'm certainly happy to direct people towards a maintained one.
>> 
>> IMO, it would also be handy if the driver wasn't pooled, but used poolboy
>> since getting the pooling right is rather difficult. (I know that poolboy
>> has been tested with some of Quviq's concurrent checking stuff and a number
>> of race conditions addressed).
>> 
>> Thanks!
>> 
>> D.
>> 
>> 
>> On Wed, Apr 10, 2013 at 3:00 PM, Henning Diedrich <>
>> wrote:
>>> 
>>> Hi Dave,
>>> 
>>> if I remember right, you were using the driver that came from Yxa via
>>> Yarif's erlang-emysql-driver https://github.com/dizzyd/erlang-mysql-driver ?
>>> (Here is the history of that. https://github.com/eonblast/Emysql#History)
>>> 
>>> It was found less than perfect when Nick and Jacob gave it something to
>>> chew building Rupture. I never spotted the problems myself I should add.
>>> That's purely from Nick Gerakine's and Jacob Vorreuter's words.
>>> 
>>> But they report that with much effort they could not get the races out of
>>> it. That's why they started emysql, which I later started maintaining, and
>>> which Jeremy just mentioned, https://github.com/eonblast/Emysql
>>> 
>>> Considerable work went into getting the pooling system of Emysql right.
>>> (What I don't know is when exactly it got buggy, it may have been after
>>> Jacob's Emysql fork that now lies dormant.) But I worked a while, with help
>>> from others to get all races out of the queuing.
>>> 
>>> However, the best fork of Emysql, I *think* is currently that of Chris
>>> Rempel at https://github.com/csrl/emysql as I got behind while making
>>> Erlvolt, the VoltDB driver, modeled in parts on Emysql. Chris did some
>>> impressive clean up. Now that Erlvolt is out, I'll turn around and catch up
>>> asap. But that's not a New York asap.
>>> 
>>> An alternative may be to go back to a more original Yxa version, like the
>>> one possibly still to be found in ejabberd. That may be more stable than
>>> Yariv's branch that you started out with. The "history" I linked to above
>>> has the reasons, why that branch may be not quite clean and hard to debug.
>>> 
>>> Best,
>>> 
>>> Henning
>>> 
>>> On Apr 10, 2013, at 10:43 PM, Dave Smith <> wrote:
>>> 
>>>> Hello list,
>>>> 
>>>> I'm curious what libraries people are currently using for MySQL access
>>>> in Erlang. I have an old library on my github that I've kept basically
>>>> working, but am wondering if there are any preferred/production libraries
>>>> out there that people like better.
>>>> 
>>>> I ask because I'm considering retrofitting the pooling system in the
>>>> driver I maintain to use poolboy, but figure it was worth checking if there
>>>> are better alternatives out there. :)
>>>> 
>>>> After all, the best code to maintain is the code you don't maintain.
>>>> 
>>>> D.
>>>> _______________________________________________
>>>> erlang-questions mailing list
>>>> 
>>>> http://erlang.org/mailman/listinfo/erlang-questions
>>> 
>> 
>> 
>> _______________________________________________
>> erlang-questions mailing list
>> 
>> http://erlang.org/mailman/listinfo/erlang-questions
>> 




More information about the erlang-questions mailing list