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https://issues.apache.org/jira/browse/CASSANDRA-4449?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sylvain Lebresne updated CASSANDRA-4449:
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Attachment: 4449.txt
Attaching patch that:
# make prepared statement global for the binary protocol. I've kept backward
compatibility on the thrift side to be conservative.
# for the binary protocol, switch the hash used as statement ID to md5, because
I don't trust String.hashCode() enough (and I don't think there is guarantees
that it cannot change between java versions).
I'd *really* like to get that in for 1.2 because I think that having
per-connection statement makes it very painful for clients library that want to
hide the details of how they perform connection pooling.
> Make prepared statement global rather than connection based
> -----------------------------------------------------------
>
> Key: CASSANDRA-4449
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4449
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Sylvain Lebresne
> Attachments: 4449.txt
>
>
> Currently, prepared statements are connection based. A client can only use a
> prepared statement on the connection it prepared it on, and if you prepare
> the same prepared statement on multiple connections, we'll keep multiple
> times the same prepared statement. This is potentially inefficient but can
> also be fairly painful for client libraries with pool of connections (a.k.a
> all reasonable client library ever) as this means you need to make sure you
> prepare statement on every connection of the pool, including the connection
> that don't exist yet but might be created later.
> This ticket suggests making prepared statement global (at least for CQL3),
> i.e. move them out of ClientState. This will likely reduce the number of
> stored statement on a given node quite a bit, since it's very likely that all
> clients to a given node will prepare the same statements (and potentially on
> all of their connection with the node). And given that prepared statement
> identifiers are the hashCode() of the string, this should be fairly trivial.
> I will note that while I think using a hash of the string as identifier is a
> very good idea, I don't know if the default java hashCode() is good enough.
> If that's a concern, maybe we should use a safer (bug longer) hash like md5
> or sha1. But we'd better do that now.
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