| From: | Thomas Kellerer <spam_eater(at)gmx(dot)net> |
|---|---|
| To: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: pg_get_expr() hangs with uncommitted DDL transaction |
| Date: | 2014-11-11 15:56:31 |
| Message-ID: | m3tbjf$ltu$1@ger.gmane.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
Tom Lane schrieb am 11.11.2014 um 16:35:
>> Is there a reason why pg_catalog.pg_get_expr() will wait until the exclusive lock on the table is released?
>
> Yes. It needs to extract attribute names, data types, etc for the target
> table and it would also like to be sure that that data is self-consistent.
> So it takes out AccessShareLock the same as a query on the table would.
Not sure I understand this.
Extracting the attribute names and data types from the various pg_catalog tables
works _without_ the query being blocked. Even when selecting all arguments that
are passed to pg_get_expr().
It's only when adding the function call to an otherwise perfectly working query
that this wait occurs.
Does this mean that pg_get_expr() selects additional data from the table,
instead of just using the values that are provided by the caller?
Thomas
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2014-11-11 16:08:46 | Re: pg_get_expr() hangs with uncommitted DDL transaction |
| Previous Message | Tom Lane | 2014-11-11 15:35:22 | Re: pg_get_expr() hangs with uncommitted DDL transaction |