Re: [Tcl-tdbc] tdbc::mysql and multiple threads...

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On Fri, Sep 02, 2016 at 12:20:27PM +0300, Georgios Petasis wrote:
> Hi all,
> 
> I want to use a mysql database from multiple threads. What I do right 
> now, is to load the packages from multiple threads, and use the database 
> as I would from a single thread.
> 
> The problem is that I am getting errors when beginning transactions. The 
> errors are about locks, timetouts, etc.

[...]

Sorry, not really specific to tdbc, but from what I know about other
similar interfaces: the database connection has a state, and this
state doesn't expect to be "seen" by independent entities (be it threads
or whatever).

Possible approaches:

 (1) Set up a separate connection handle for each thread.

 (2) Use some cunning scheme which somehow manages this
     state, creating an illusion of a private handle
     per client (instance). Traditionally this is called
     "connection pooling" and implemented by having one
     thread handling the mess on behalf of the others.

That said, perhaps ODBC is smarter than I think and pretends to do
that for you: then that'd be a bug :-)

(Sorry if you knew all of this. Perhaps I just failed to gather that
from your question).

regards
- -- t
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