Markus Demleitner writes:
> On Tue, May 13, 2025 at 10:12:46AM -0400, Tom Lane wrote:
>> Oh, well, that's your problem. The source tables' column types
>> need to match. Otherwise the UNIONs don't get flattened and you
>> don't get indexscans.
> A... *source* tables. Sure, once I'm out of
Dear Tom,
On Tue, May 13, 2025 at 10:12:46AM -0400, Tom Lane wrote:
> Markus Demleitner writes:
> > SELECT
> > CAST(ssa_dstype AS text) AS dataproduct_type,
> > CAST(NULL AS text) AS dataproduct_subtype,
> > CAST(2 AS smallint) AS calib_level,
> > ...
>
> Oh, well, that's your p
Markus Demleitner writes:
> You see, when creating the "big", 30-tables view, I do cast all
> columns to common types in the view statement that actually make up
> the view. The original SQL fragments look like this:
> SELECT
> CAST(ssa_dstype AS text) AS dataproduct_type,
> CAST(NULL
Dear Tom, Dear Laurenz,
Thanks for your pointers -- that was already helpful.
On Thu, May 01, 2025 at 06:58:45AM +0200, Laurenz Albe wrote:
> On Wed, 2025-04-30 at 17:02 -0400, Tom Lane wrote:
> > It's hard to be sure when you've shown us no table definitions and
> > only fragments of the view de
"Peter J. Holzer" writes:
> On 2025-04-30 17:16:47 +0200, Markus Demleitner wrote:
>> dfbsspec.raw_spectra is about 23 Megarows,
>> -> Parallel Seq Scan on raw_spectra (cost=0.00..2626995.66 rows=5803266
>> width=756) (actual time=0.137..6841.379 rows=4642657 loops=5)
> It estimates that it ha
On 2025-04-30 17:16:47 +0200, Markus Demleitner wrote:
> There is another view made up of about 20 tables, looking somewhat
> like this:
[...]
> The first view, ivoa.obs_radio, is just a few hundred records,
> dfbsspec.raw_spectra is about 23 Megarows,
[...]
>
On Wed, 2025-04-30 at 17:02 -0400, Tom Lane wrote:
> Markus Demleitner writes:
> > So, when the SELECT statement on dfbsspec.ssa stands along in the view
> > definition, Postgres does the right thing; when the exact same query
> > stands in a UNION ALL with other tables, Postgres doesn't use the
>
Markus Demleitner writes:
> So, when the SELECT statement on dfbsspec.ssa stands along in the view
> definition, Postgres does the right thing; when the exact same query
> stands in a UNION ALL with other tables, Postgres doesn't use the
> index. Hu?
It's hard to be sure when you've shown us no
On Wed, Apr 30, 2025 at 3:51 PM Markus Demleitner <
msdem...@ari.uni-heidelberg.de> wrote:
> Dear List,
>
> I know how tedious mails with a subject of the type "I don't understand
> what the planner does" are, but on this one I'm really stumped.
> Regrettably, the situation is also a bit complex.
