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concurrent connections

Ledion Bitincka
Are there any recommendations on the maximum number of concurrent connections? In my usecase almost all the connections will be reading data. I have seen that with other db systems the performance drops dramatically as the number of concurrent connections gets to a couple of hundred. Is luciddb the same in this regard? Are there any explicit system setting to limit the number of concurrent connections?
 
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Ledion Bitincka
[hidden email] | Director of Engineering, Southern California Regional Operations
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Re: concurrent connections

John Sichi
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On Tue, Mar 8, 2011 at 10:54 PM, Ledion Bitincka <[hidden email]> wrote:
> Are there any recommendations on the maximum number of concurrent
> connections? In my usecase almost all the connections will be reading data.
> I have seen that with other db systems the performance drops dramatically as
> the number of concurrent connections gets to a couple of hundred. Is luciddb
> the same in this regard? Are there any explicit system setting to limit the
> number of concurrent connections?

There's no governance on concurrent connections (use a connection pool
for that), but system parameter "expectedConcurrentStatements" is used
to ration out the buffer pool.  For small queries, it doesn't matter
since each query only needs to pin a few blocks in the buffer pool,
but for large/complex queries it matters.

You'll know you need to increase it (and/or the buffer pool size) if
you hit "Cache scratch memory exhausted".  Or throttle via connection
pooling.

JVS

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Colocation vs. Managed Hosting
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