| From: | Pavan Deolasee <pavan(dot)deolasee(at)gmail(dot)com> |
|---|---|
| To: | Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> |
| Cc: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Bruce Momjian <bruce(at)momjian(dot)us>, Jaime Casanova <jaime(dot)casanova(at)2ndquadrant(dot)com>, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Patch: Write Amplification Reduction Method (WARM) |
| Date: | 2017-03-28 17:05:53 |
| Message-ID: | CABOikdNEVMO0MGtk4PuBsACitHKuQ6MC6Gi-_R-gR_aDAUz_PA@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, Mar 28, 2017 at 7:04 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
>
>
> For such an heap insert, we will pass
> the actual value of column to index_form_tuple during index insert.
> However during recheck when we fetch the value of c2 from heap tuple
> and pass it index tuple, the value is already in compressed form and
> index_form_tuple might again try to compress it because the size will
> still be greater than TOAST_INDEX_TARGET and if it does so, it might
> make recheck fail.
>
>
Would it? I thought "if
(!VARATT_IS_EXTENDED(DatumGetPointer(untoasted_values[i]))" check should
prevent that. But I could be reading those macros wrong. They are probably
heavily uncommented and it's not clear what each of those VARATT_* macro do.
Thanks,
Pavan
--
Pavan Deolasee http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Alvaro Herrera | 2017-03-28 17:26:08 | Re: [COMMITTERS] pgsql: Allow vacuums to report oldestxmin |
| Previous Message | Dave Page | 2017-03-28 17:04:00 | Re: Monitoring roles patch |