Re: [HACKERS] Microvacuum support for Hash Index - Mailing list pgsql-hackers

From Ashutosh Sharma
Subject Re: [HACKERS] Microvacuum support for Hash Index
Date
Msg-id CAE9k0PnkFBpGbz5feX4qA2F4rx5qYmsxfWu5wM85ZM1Rc9TkyA@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] Microvacuum support for Hash Index  (Amit Kapila <amit.kapila16@gmail.com>)
Responses Re: [HACKERS] Microvacuum support for Hash Index  (Amit Kapila <amit.kapila16@gmail.com>)
List pgsql-hackers
On Fri, Mar 17, 2017 at 6:13 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Fri, Mar 17, 2017 at 12:27 PM, Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
>> On Fri, Mar 17, 2017 at 8:20 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>>
>> As I said in my previous e-mail, I think you need
>>> to record clearing of this flag in WAL record XLOG_HASH_DELETE as you
>>> are not doing this unconditionally and then during replay clear it
>>> only when the WAL record indicates the same.
>>
>> Thank you so much for putting that point. I too think that we should
>> record the flag status in the WAL record and clear it only when
>> required during replay.
>>
>
> I think hashdesc.c needs an update (refer case XLOG_HASH_DELETE:).

Done. Thanks!

>
> - * flag. Clearing this flag is just a hint; replay won't redo this.
> + * flag. Clearing this flag is just a hint; replay will check the
> + * status of clear_dead_marking flag before redo it.
>   */
>   if (tuples_removed && *tuples_removed > 0 &&
>   opaque->hasho_flag & LH_PAGE_HAS_DEAD_TUPLES)
> + {
>   opaque->hasho_flag &= ~LH_PAGE_HAS_DEAD_TUPLES;
> + clear_dead_marking = true;
> + }
>
>
> I feel the above comment is not required as you are logging this
> action explicitly.

That's right. I have removed it in the attached v4 patch.

>
> + bool clear_dead_marking; /* TRUE if VACUUM clears
>
> No need to write VACUUM explicitly, you can simply say "TRUE if this
> operation clears ...".

Corrected. Please find the attached v4 patch.

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com

-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers

Attachment

pgsql-hackers by date:

Previous
From: Peter Eisentraut
Date:
Subject: Re: [HACKERS] PATCH: pageinspect / add page_checksum andbt_page_items(bytea)
Next
From: Alvaro Herrera
Date:
Subject: [HACKERS] Re: [COMMITTERS] pgsql: Remove objname/objargs split for referringto objects