Re: Adding new dependencies for in-core - Mailing list pgsql-jdbc

I see. Just to throw in a different idea: Possibly we might need caches in
other places too at a later time, so maybe we might like to apply strategy
design pattern instead of becoming directly dependent of one particular
class? I mean, it is nice that the linked hash map actually implies LRU, but
if we want LRU, it might be a better design choice, to explicitly model this
as a class "LruCacheStrategy" which allows us to even configure or replace
the strategy later?

-----Original Message-----
From: Steven Schlansker [mailto:stevenschlansker@gmail.com]
Sent: Dienstag, 30. Juni 2015 19:09
To: Markus KARG
Cc: List
Subject: Re: [JDBC] Adding new dependencies for in-core

It is a Concurrent *Linked* HashMap, which presumably facilitates LRU
removal.

On Jun 30, 2015, at 10:06 AM, Markus KARG <markus@headcrashing.eu> wrote:

> Vladimir,
>
> sorry for being so ingorant not to give it a deeper thought, but what is
in CLHM what is not also in java.util.concurrent.ConcurrentHashMap?
>
> -Markus
>
> -----Original Message-----
> From: pgsql-jdbc-owner@postgresql.org
[mailto:pgsql-jdbc-owner@postgresql.org] On Behalf Of Vladimir Sitnikov
> Sent: Dienstag, 30. Juni 2015 14:21
> To: List
> Subject: [JDBC] Adding new dependencies for in-core
>
> Hi,
>
> I've had a quick look into https://github.com/pgjdbc/pgjdbc/issues/345
> (Share parsed query texts across different connections) and it looks like
https://github.com/ben-manes/concurrentlinkedhashmap would be useful to
implement the cache.
>
> We don't need all the stuff CLHM has, but I see no easy&scalable way of
doing concurrent map with eviction by mere java.util.concurrent stuff.
>
> Well, I can do lock splitting (i.e. use multiple small LRU caches instead
of a single big cache), however that looks like reinventing the wheel.
>
> Can you suggest what is the best way of adding CLHM dependency?
> Should it be added in plain?
> Should it be shaded? (i.e. renamed to org.postgresql.clhm...)
>
> I'm more inclined to the "add regular dependency" approach.
>
> I expect similar question might appear if we consider using netty for IO.
>
> --
> Regards,
> Vladimir Sitnikov
>
>
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