| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>,Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
| Cc: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Freezing without cleanup lock |
| Date: | 2015-10-21 19:52:23 |
| Message-ID: | 380530E1-91C6-4E99-A045-0EAFE8E872F1@anarazel.de |
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| Lists: | pgsql-hackers |
On October 21, 2015 9:47:45 PM GMT+02:00, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> writes:
>> While warning a client that just did a Slony-based version upgrade to
>
>> make sure to freeze the new database, it occurred to me that it
>should
>> be safe to freeze without the cleanup lock.
>
>What's your argument for that being safe?
It doesn't affect tuple contents and thus backends having a pin can continue looking at tuple contents. The reason we need a cleanup lock is IIRC repairing page fragmentation / hot pruning, not freezing.
Andres
---
Please excuse brevity and formatting - I am writing this on my mobile phone.
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