Re: [PROPOSAL] Shared Ispell dictionaries

On 03/07/2018 02:18 PM, Arthur Zakirov wrote:
> On Wed, Mar 07, 2018 at 02:12:32PM +0100, Pavel Stehule wrote:
>> 2018-03-07 14:10 GMT+01:00 Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>:
>>> 2018-03-07 13:58 GMT+01:00 Arthur Zakirov <a(dot)zakirov(at)postgrespro(dot)ru>:
>>>> Oh understood. Tomas suggested those commands too earlier. I'll
>>>> implement them. But I think it is better to track files modification time
>>>> too. Because now, without the patch, users don't have to call additional
>>>> commands to refresh their dictionaries, so without such tracking we'll
>>>> made dictionaries maintenance harder.
>>>>
>>>
>>> Postgres hasn't any subsystem based on modification time, so
>>> introduction this sensitivity, I don't see, practical.
>>>
>>
>> Usually the shared dictionaries are used for complex language
>> based fulltext. The frequence of updates of these dictionaries is
>> less than updates PostgreSQL. The czech dictionary is same 10
>> years.
>
> Agree. In this case auto reloading isn't important feature here.
>

Arthur, what are your plans with this patch in the current CF?

It does not seem to be moving towards RFC very much, and reworking the
patch to use mmap() seems like a quite significant change late in the
CF. Which means it's likely to cause the patch get get bumped to the
next CF (2018-09).

FWIW I am not quite sure if the mmap() approach is better than what was
implemented by the patch. I'm not sure how exactly will it behave under
memory pressure (AFAIK it goes through page cache, which means random
parts of dictionaries might get evicted) or how well is it supported on
various platforms (say, Windows).

regards

--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services