Subject: Re: "debug_invalidate_system_caches_always" is too long
To: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>,
 Tom Lane <tgl@sss.pgh.pa.us>
Cc: Noah Misch <noah@leadboat.com>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
References: <1374320.1625430433@sss.pgh.pa.us>
 <20210704211234.GD2421985@rfd.leadboat.com>
 <1492832.1625512421@sss.pgh.pa.us>
 <CALj2ACVT4ga=RDYsBzLg3DXg2ENat2V-eh4yw8oH65Z1CNkJ6g@mail.gmail.com>
From: Andrew Dunstan <andrew@dunslane.net>
Message-ID: <5f1332ab-d2ee-e31d-ecf7-62cc7d150b09@dunslane.net>
Date: Tue, 6 Jul 2021 05:50:14 -0400
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On 7/5/21 11:46 PM, Bharath Rupireddy wrote:
> On Tue, Jul 6, 2021 at 12:43 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Noah Misch <noah@leadboat.com> writes:
>>> On Sun, Jul 04, 2021 at 04:27:13PM -0400, Tom Lane wrote:
>>>> However, I think we should also give serious consideration to
>>>> "debug_clobber_cache" or "debug_clobber_cache_always" for continuity
>>>> with past practice (though it still feels like "always" is a good
>>>> word to lose now).  "debug_clobber_caches" is another reasonable
>>>> variant.
>>> https://en.wikipedia.org/wiki/Clobbering refers to cases where storage had no
>>> changes to its accessibility but now contains different data.  That doesn't
>>> match InvalidateSystemCaches() especially well, so I think dropping that word
>>> has been a good step.  Some other shorter terms could be debug_flush_caches,
>>> debug_rebuild_caches, or debug_expire_caches.  (debug_caches is tempting, but
>>> that may ensnare folks looking for extra logging rather than a big slowdown.)
>> I like "debug_flush_caches" --- it's short and accurate.
> Do we always flush the cache entries into the disk? Sometimes we just
> invalidate the cache entries in the registered invalidation callbacks,
> right? Since we already use the term "clobber" in the user visible
> config option --clobber-cache, isn't it consistent to use
> debug_clobber_caches?
>

I think 'flush' here means simply 'discard'. Maybe that would be a
better word to use.


cheers


andrew

--
Andrew Dunstan
EDB: https://www.enterprisedb.com