Re: PATCH: Add REINDEX tag to event triggers

On Mon, Sep 04, 2023 at 08:00:52PM +0200, Jim Jones wrote:
> LGTM. It applies and builds cleanly, all tests pass and documentation also
> builds ok. The CFbot seems also much happier now :)

+	/*
+	 * Open and lock the relation.  ShareLock is sufficient since we only need
+	 * to prevent schema and data changes in it.  The lock level used here
+	 * should match catalog's reindex_relation().
+	 */
+	rel = try_table_open(relid, ShareLock);

I was eyeing at 0003, and this strikes me as incorrect.  Sure, this
matches what reindex_relation() does, but you've missed that
CONCURRENTLY takes a lighter ShareUpdateExclusiveLock, and ShareLock
conflicts with it.  See:
https://www.postgresql.org/docs/devel/explicit-locking.html

So, doesn't this disrupt a concurrent REINDEX?
--
Michael