| From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
|---|---|
| To: | Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, Andres Freund <andres(at)anarazel(dot)de>, Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com, robertmhaas(at)gmail(dot)com, tgl(at)sss(dot)pgh(dot)pa(dot)us, ideriha(dot)takeshi(at)jp(dot)fujitsu(dot)com, pgsql-hackers(at)lists(dot)postgresql(dot)org, michael(dot)paquier(at)gmail(dot)com, david(at)pgmasters(dot)net, craig(at)2ndquadrant(dot)com |
| Subject: | Re: Protect syscache from bloating with negative cache entries |
| Date: | 2019-02-18 13:49:56 |
| Message-ID: | 20190218134956.GA909@alvherre.pgsql |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2019-Feb-15, Tomas Vondra wrote:
> ISTM there's a couple of ways to deal with that:
>
> 1) Ignore the memory amounts entirely, and do just time-base eviction.
>
> 2) If we want some size thresholds (e.g. to disable eviction for
> backends with small caches etc.) use the number of entries instead. I
> don't think that's particularly worse that specifying size in MB.
Why is there a *need* for size-based eviction? Seems that time-based
should be sufficient. Is the proposed approach to avoid eviction at all
until the size threshold has been reached? I'm not sure I see the point
of that.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Andrew Dunstan | 2019-02-18 13:56:19 | Re: Ryu floating point output patch |
| Previous Message | Alvaro Herrera | 2019-02-18 13:45:38 | Re: Incorrect visibility test function assigned to snapshot |