Re: Allow CLUSTER, VACUUM FULL and REINDEX to change tablespace on the fly - Mailing list pgsql-hackers

From Zhihong Yu
Subject Re: Allow CLUSTER, VACUUM FULL and REINDEX to change tablespace on the fly
Date
Msg-id CALNJ-vQeFpTdTgHdU4fcO94pRcxpAC7X5ujeM06rUHoKwgO5Sg@mail.gmail.com
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In response to Re: Allow CLUSTER, VACUUM FULL and REINDEX to change tablespace on the fly  (Peter Eisentraut <peter.eisentraut@enterprisedb.com>)
List pgsql-hackers
Justin:
For reindex_index() :

+   if (options->tablespaceOid == MyDatabaseTableSpace)
+       options->tablespaceOid = InvalidOid;
...
+   if (set_tablespace &&
+       (options->tablespaceOid != oldTablespaceOid ||
+       (options->tablespaceOid == MyDatabaseTableSpace && OidIsValid(oldTablespaceOid))))

I wonder why the options->tablespaceOid == MyDatabaseTableSpace clause appears again in the second if statement.
Since the first if statement would assign InvalidOid to options->tablespaceOid when the first if condition is satisfied.

Cheers


On Tue, Dec 22, 2020 at 1:15 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
On Tue, Dec 22, 2020 at 06:57:41PM +0900, Michael Paquier wrote:
> On Tue, Dec 22, 2020 at 02:32:05AM -0600, Justin Pryzby wrote:
> > Also, this one is going to be subsumed by ExecReindex(), so the palloc will go
> > away (otherwise I would ask to pass it in from the caller):
>
> Yeah, maybe.  Still you need to be very careful if you have any
> allocated variables like a tablespace or a path which requires to be
> in the private context used by ReindexMultipleInternal() or even
> ReindexRelationConcurrently(), so I am not sure you can avoid that
> completely.  For now, we could choose the option to still use a
> palloc(), and then save the options in the private contexts.  Forgot
> that in the previous version actually.

I can't see why this still uses memset instead of structure assignment.

Now, I really think utility.c ought to pass in a pointer to a local
ReindexOptions variable to avoid all the memory context, which is unnecessary
and prone to error.

ExecReindex() will set options.tablesapceOid, not a pointer.  Like this.

I also changed the callback to be a ReindexOptions and not a pointer.

--
Justin

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