Re: Re: Recursive use of syscaches (was: relation ### modified while in use) - Mailing list pgsql-hackers

From Hiroshi Inoue
Subject Re: Re: Recursive use of syscaches (was: relation ### modified while in use)
Date
Msg-id 3A0B5061.53D60701@tpf.co.jp
Whole thread Raw
In response to RE: relation ### modified while in use  ("Hiroshi Inoue" <Inoue@tpf.co.jp>)
Responses Re: Re: Recursive use of syscaches (was: relation ### modified while in use)  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
Tom Lane wrote:

> Hiroshi Inoue <Inoue@tpf.co.jp> writes:
> > My concern is the robustness of rel cache.
> > It seems pretty dangerous to discard system relation
> > descriptors used for cache mechanism especially in
> > case of error recovery.
> > It also seems pretty dangerous to recontruct relation
> > descriptors especially in case of error recovery.
>
> Why?  We are able to construct all the non-nailed relcache entries
> from scratch during backend startup.  That seems a sufficient
> proof that we can reconstruct any or all of them on demand.
>


Hmm,why is it sufficent ?
At backend startup there are no rel cache except
some nailed rels. When 'reset system cache' message
arrives,there would be many rel cache entries and
some of them may be in use.
In addtion there could be some inconsitency of db
in the middle of the transaction. Is it safe to recon
struct rel cache under the inconsistency ?

Regards.
Hiroshi Inoue



pgsql-hackers by date:

Previous
From: "Kevin O'Gorman"
Date:
Subject: Tip of current tree: Seg fault in query
Next
From: Tom Lane
Date:
Subject: Re: 7.0.2 dies when connection dropped mid-transaction