From: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
---|---|
To: | Marti Raudsepp <marti(at)juffo(dot)org> |
Cc: | Noah Misch <noah(at)leadboat(dot)com>, Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: RFC: Making TRUNCATE more "MVCC-safe" |
Date: | 2012-03-04 16:39:58 |
Message-ID: | CA+U5nM+wnEm-efOaAVKNJbQ8fhCk6eKFNkVHq5A2MQB2UM_XaQ@mail.gmail.com |
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Lists: | pgsql-hackers |
On Sun, Mar 4, 2012 at 1:02 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> On Sun, Mar 4, 2012 at 9:59 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> On Sun, Mar 4, 2012 at 2:28 AM, Marti Raudsepp <marti(at)juffo(dot)org> wrote:
>>> On Sat, Mar 3, 2012 at 14:53, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>>>> Thanks Noah for drawing attention to this thread. I hadn't been
>>>> watching. As you say, this work would allow me to freeze rows at load
>>>> time and avoid the overhead of hint bit setting, which avoids
>>>> performance issues from hint bit setting in checksum patch.
>>>>
>>>> I've reviewed this patch and it seems OK to me. Good work Marti.
>
> ...
>
>> v3 attached.
>
> More detailed thoughts show that the test in heap_beginscan_internal()
> is not right enough, i.e. wrong.
>
> We need a specific XidInMVCCSnapshot test on the relvalidxid, so it
> needs to be a specific xid, not an xmin because otherwise we can get
> concurrent transactions failing, not just older transactions.
Marti, please review this latest version which has new isolation tests added.
This does both TRUNCATE and CREATE TABLE.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
Attachment | Content-Type | Size |
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strictmvcc.v1.patch | text/x-diff | 23.3 KB |
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