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From Marcel May <marcel....@consol.de>
Subject Re: Multiple connections (Was: Jackrabbit, the database)
Date Tue, 21 Aug 2007 09:43:46 GMT
Thomas Mueller wrote:
>> avoid the synchronization on the PreparedStatements
>>     
>
> I don't think that synchronization on prepared statements is a
> bottleneck. But you can prove that I am wrong. If writing the
> changelog is synchronized (not sure if it is), that would be a
> bottleneck.
>
> Thomas
>   
The 'synchronization' can also be described as serialization of all DB
acccess.
A single DB connection can only process a single operation at a time.
Jackrabbit locks up completely while storing (example: a larger binary)
- not only for reading but also for writing.
There has been some improvements AFAIK, but it still applies for write
operations.
A simple insert of 10MB will look up JR for few seconds, this is quite a
problem IMO.

Another advantage is that jdbc pools can health check connections.
This reduces the complex firewall- or database- 'closed connection
reconnect' logic ... if not making it redunant.
This improves stability.

Also nice: pools usually are often monitorable, most app servers support
this.

Cheers,
Marcel

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