| From: | Kevin Grittner <kgrittn(at)ymail(dot)com> |
|---|---|
| To: | Noah Misch <noah(at)leadboat(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, "pgsql-hackers(at)postgreSQL(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: matview scannability rehash (was Re: Drastic performance loss in assert-enabled build in HEAD) |
| Date: | 2013-04-05 14:00:38 |
| Message-ID: | 1365170438.21865.YahooMailNeo@web162903.mail.bf1.yahoo.com |
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| Lists: | pgsql-hackers |
Noah Misch <noah(at)leadboat(dot)com> wrote:
> The SQL commands I cited as responsible for creating or removing
> the fork all make a new relfilenode anyway. Thus, "add" actually
> means creating the fork with the new relfilenode, and "remove"
> actually means omitting the fork from the new relfilenode. The
> association between relfilenodes and relations is, of course,
> transactional.
The same argument applies to the currently-committed code. The
goal is to not change a matview between zero-length and non-zero
length once the heap exists; but to only have this state change
when REFRESH replaces the heap in the style of CLUSTER, TRUNCATE,
ALTER TABLE with heap rewrite, or the new VACUUM FULL.
--
Kevin Grittner
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company
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