From: | Julien Rouhaud <rjuju123(at)gmail(dot)com> |
---|---|
To: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Peter Geoghegan <pg(at)bowt(dot)ie>, "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, Greg Stark <stark(at)mit(dot)edu>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: 64-bit queryId? |
Date: | 2017-10-18 13:20:06 |
Message-ID: | CAOBaU_a8AH8=ypfqgHnDYu06ts+jWTUgh=VgCxA3yNV-K10j9w@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On Thu, Oct 12, 2017 at 2:46 AM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
> On Thu, Oct 12, 2017 at 9:05 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>> On Wed, Oct 4, 2017 at 9:00 PM, Michael Paquier
>> <michael(dot)paquier(at)gmail(dot)com> wrote:
>>> v4 looks correct to me. Testing it through (pgbench and some custom
>>> queries) I have not spotted issues. If the final decision is to use
>>> 64-bit query IDs, then this patch could be pushed.
>>
>> Cool. Committed, thanks for the review.
>
> The final result looks fine for me. Thanks.
Sorry for replying so late, but I have a perhaps naive question about
the hashtable handling with this new version.
IIUC, the shared hash table is now created with HASH_BLOBS instead of
HASH_FUNCTION, so since sizeof(pgssHashKey) != sizeof(uint32) the hash
table will use tag_hash() to compute the hash key.
tag_hash() uses all the bits present in the given struct, so this can
be problematic if padding bits are not zeroed, which isn't garanted by
C standard for local variable.
WIth current pgssHashKey definition, there shouldn't be padding bits,
so it should be safe. But I wonder if adding an explicit memset() of
the key in pgss_store() could avoid extension authors to have
duplicate entries if they rely on this code, or prevent future issue
in the unlikely case of adding other fields to pgssHashKey.
From | Date | Subject | |
---|---|---|---|
Next Message | Alvaro Herrera | 2017-10-18 15:27:41 | Re: [COMMITTERS] pgsql: Implement table partitioning. |
Previous Message | Alvaro Herrera | 2017-10-18 11:37:22 | Re: alter table doc fix |