| From: | Josh Berkus <josh(at)agliodbs(dot)com> |
|---|---|
| To: | Andres Freund <andres(at)2ndquadrant(dot)com> |
| Cc: | Bruce Momjian <bruce(at)momjian(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, Jeff Davis <pgsql(at)j-davis(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: removing PD_ALL_VISIBLE |
| Date: | 2013-05-31 17:28:12 |
| Message-ID: | 51A8DDAC.3040109@agliodbs.com |
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| Thread: | |
| Lists: | pgsql-hackers |
>> Isn't the visibility map already required for proper return results as
>> we use it for index-only scans. I think the optimization-only ship has
>> sailed.
>
> At the moment we can remove it without causing corruption. If we were to
> use it for freezing we couldn't anymore. So there's a difference - how
> big it is I am not sure.
Depends on your definition of corruption, really.
But yes, right now, the vismap can lose bits without causing any
corruption, and making all-frozen depend on it would eliminate that.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com
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