Re: [GENERAL] huge table occupation after updates - Mailing list pgsql-general

From t.dalpozzo@gmail.com
Subject Re: [GENERAL] huge table occupation after updates
Date
Msg-id 584E68D7.10108@gmail.com
Whole thread Raw
In response to Re: [GENERAL] huge table occupation after updates  ("David G. Johnston" <david.g.johnston@gmail.com>)
List pgsql-general
Il 12/12/2016 02:42, David G. Johnston ha scritto:
On Saturday, December 10, 2016, Tom DalPozzo <t.dalpozzo@gmail.com> wrote:

​I have one direct DB client (let's name it MIDAPP) only. This client of the DB is a server for up to 10000 final clients.
Any time MIDAPP is going to reply to a client, it must save a "status record with some data" related to that client and only after that, answering /committing the final client.
The next time the same final client will ask something, the same status record will be updated again (with a different content).

Why do you want to pay for concurrency control when you don't seem to need it?  While PostgreSQL likely can do what you need I suspect there are applications out there that can solve this specific problem better.  Even something as simple as a flat file, one per "final client", written atomically and fsynced after each write/rename.

David J,
Hi David,
 there are also other DB clients which only perform read queries using SQL. It's the reason why I chose postgreSQL over simpler apps. I didn't mention about them so far as those queries are not a concern in terms of performance.

Anyway, regarding the huge dimension of the table,  I think that reason was that autovacuum didn't work as the updates traffic was really high in my test, with no pause. Infact, if I lower it down to 1500updates/sec, then autovacuum works (I checked the log).
So the table size can grow but not for ever as it gets reused.
Thank you very much.

Pupillo





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