v10beta pg_catalog diagrams

On 6/12/17 11:28, Neil Anderson wrote:

I'm cross posting from general. I did some work to diagram the
relationships in pg_catalog for v10. I would like to add it to the
developer FAQ here
https://wiki.postgresql.org/wiki/Developer_FAQ#Is_there_a_diagram_of_the_system_catalogs_available.3F
but I thought I should check if people thought it appropriate and useful
before I do?

https://www.postgrescompare.com/2017/06/11/pg_catalog_constraints.html

Go for it.

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On Mon, Jun 12, 2017 at 04:07:35PM -0400, Peter Eisentraut wrote:

On 6/12/17 11:28, Neil Anderson wrote:

I'm cross posting from general. I did some work to diagram the
relationships in pg_catalog for v10. I would like to add it to the
developer FAQ here
https://wiki.postgresql.org/wiki/Developer_FAQ#Is_there_a_diagram_of_the_system_catalogs_available.3F
but I thought I should check if people thought it appropriate and useful
before I do?

https://www.postgrescompare.com/2017/06/11/pg_catalog_constraints.html

Go for it.

Yeah, great. We have been talking about adding diagrams to our
official docs but needed an updated toolchain, which I think we now
have, so there is a lot of opportunity for growth here.

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On 2017-06-13 1:22 PM, Bruce Momjian wrote:

On Mon, Jun 12, 2017 at 04:07:35PM -0400, Peter Eisentraut wrote:

On 6/12/17 11:28, Neil Anderson wrote:

I'm cross posting from general. I did some work to diagram the
relationships in pg_catalog for v10. I would like to add it to the
developer FAQ here
https://wiki.postgresql.org/wiki/Developer_FAQ#Is_there_a_diagram_of_the_system_catalogs_available.3F
but I thought I should check if people thought it appropriate and useful
before I do?

https://www.postgrescompare.com/2017/06/11/pg_catalog_constraints.html

Go for it.

Yeah, great. We have been talking about adding diagrams to our
official docs but needed an updated toolchain, which I think we now
have, so there is a lot of opportunity for growth here.

Wonderful. I've added it.

There were a few relationships that I couldn't capture. Like where in
pg_extension extconfig is an array of oids that refer to pg_class or
where pg_depends could refer to basically any other system catalog, but
it's mostly there and has all 62 tables from pg_catalog.

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On Tue, Jun 13, 2017 at 3:14 PM, Neil Anderson <neil@postgrescompare.com> wrote:

There were a few relationships that I couldn't capture. Like where in
pg_extension extconfig is an array of oids that refer to pg_class or where
pg_depends could refer to basically any other system catalog, but it's
mostly there and has all 62 tables from pg_catalog.

At the risk of tooting my own horn, if you happen to have a damaged
database where you think that the pseudo-foreign-key relationships
don't actually hold, you can run
https://github.com/EnterpriseDB/pg_catcheck to find the problems. It
checks things like extconfig and pg_depend links, too.

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Hi,

On 2017-06-12 11:28:39 -0400, Neil Anderson wrote:

I'm cross posting from general. I did some work to diagram the relationships
in pg_catalog for v10. I would like to add it to the developer FAQ here https://wiki.postgresql.org/wiki/Developer_FAQ#Is_there_a_diagram_of_the_system_catalogs_available.3F
but I thought I should check if people thought it appropriate and useful
before I do?

https://www.postgrescompare.com/2017/06/11/pg_catalog_constraints.html

I wondered before if we shouldn't introduce "information only"
unenforced foreign key constraints for the catalogs. We kind of
manually do that via oidjoins, it'd be nicer if we'd a function
rechecking fkeys, and the fkeys were in the catalog...

- Andres

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On 6/13/17 17:08, Andres Freund wrote:

I wondered before if we shouldn't introduce "information only"
unenforced foreign key constraints for the catalogs. We kind of
manually do that via oidjoins, it'd be nicer if we'd a function
rechecking fkeys, and the fkeys were in the catalog...

I don't see why we couldn't just add a full complement of primary and
foreign key constraints (and unique constraints and perhaps some check
constraints). The argument is that they wouldn't normally do anything,
but they would help with documentation and browsing tools, and they
wouldn't hurt anything.

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PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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2017-06-14 5:53 GMT+02:00 Peter Eisentraut <peter.eisentraut@2ndquadrant.com

:

On 6/13/17 17:08, Andres Freund wrote:

I wondered before if we shouldn't introduce "information only"
unenforced foreign key constraints for the catalogs. We kind of
manually do that via oidjoins, it'd be nicer if we'd a function
rechecking fkeys, and the fkeys were in the catalog...

I don't see why we couldn't just add a full complement of primary and
foreign key constraints (and unique constraints and perhaps some check
constraints). The argument is that they wouldn't normally do anything,
but they would help with documentation and browsing tools, and they
wouldn't hurt anything.

These constraints can slowdown creating/dropping database objects - mainly
temp tables.

Regards

Pavel

On 2017-06-14 06:05:24 +0200, Pavel Stehule wrote:

2017-06-14 5:53 GMT+02:00 Peter Eisentraut <peter.eisentraut@2ndquadrant.com

:

On 6/13/17 17:08, Andres Freund wrote:

I wondered before if we shouldn't introduce "information only"
unenforced foreign key constraints for the catalogs. We kind of
manually do that via oidjoins, it'd be nicer if we'd a function
rechecking fkeys, and the fkeys were in the catalog...

I don't see why we couldn't just add a full complement of primary and
foreign key constraints (and unique constraints and perhaps some check
constraints). The argument is that they wouldn't normally do anything,
but they would help with documentation and browsing tools, and they
wouldn't hurt anything.

Well, unique constraints are a bit more complicated because they rely on
an index, and we wouldn't e.g. maintain indexes with WHERE clauses or
other expressions correctly. I'd be a bit wary of declaring such
indexes as actually being fully valid, because we have planner logic
that does planning based on various constraints now, it'd certainly be
annoying if some "re-check constraint" type queries would actually have
their joins optimized away or such...

These constraints can slowdown creating/dropping database objects - mainly
temp tables.

How so?

- Andres

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2017-06-14 19:49 GMT+02:00 Andres Freund <andres@anarazel.de>:

On 2017-06-14 06:05:24 +0200, Pavel Stehule wrote:

2017-06-14 5:53 GMT+02:00 Peter Eisentraut <

peter.eisentraut@2ndquadrant.com

:

On 6/13/17 17:08, Andres Freund wrote:

I wondered before if we shouldn't introduce "information only"
unenforced foreign key constraints for the catalogs. We kind of
manually do that via oidjoins, it'd be nicer if we'd a function
rechecking fkeys, and the fkeys were in the catalog...

I don't see why we couldn't just add a full complement of primary and
foreign key constraints (and unique constraints and perhaps some check
constraints). The argument is that they wouldn't normally do anything,
but they would help with documentation and browsing tools, and they
wouldn't hurt anything.

Well, unique constraints are a bit more complicated because they rely on
an index, and we wouldn't e.g. maintain indexes with WHERE clauses or
other expressions correctly. I'd be a bit wary of declaring such
indexes as actually being fully valid, because we have planner logic
that does planning based on various constraints now, it'd certainly be
annoying if some "re-check constraint" type queries would actually have
their joins optimized away or such...

These constraints can slowdown creating/dropping database objects -

mainly

temp tables.

How so?

execution RI triggers

Regards

Pavel

On June 14, 2017 7:53:05 PM PDT, Pavel Stehule <pavel.stehule@gmail.com> wrote:

2017-06-14 19:49 GMT+02:00 Andres Freund <andres@anarazel.de>:

On 2017-06-14 06:05:24 +0200, Pavel Stehule wrote:

2017-06-14 5:53 GMT+02:00 Peter Eisentraut <

peter.eisentraut@2ndquadrant.com

:

On 6/13/17 17:08, Andres Freund wrote:

I wondered before if we shouldn't introduce "information only"
unenforced foreign key constraints for the catalogs. We kind

of

manually do that via oidjoins, it'd be nicer if we'd a function
rechecking fkeys, and the fkeys were in the catalog...

I don't see why we couldn't just add a full complement of primary

and

foreign key constraints (and unique constraints and perhaps some

check

constraints). The argument is that they wouldn't normally do

anything,

but they would help with documentation and browsing tools, and

they

wouldn't hurt anything.

Well, unique constraints are a bit more complicated because they rely

on

an index, and we wouldn't e.g. maintain indexes with WHERE clauses or
other expressions correctly. I'd be a bit wary of declaring such
indexes as actually being fully valid, because we have planner logic
that does planning based on various constraints now, it'd certainly

be

annoying if some "re-check constraint" type queries would actually

have

their joins optimized away or such...

These constraints can slowdown creating/dropping database objects -

mainly

temp tables.

How so?

execution RI triggers

Those would obviously bit be fired, given Peter's description?

Andres
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2017-06-15 5:02 GMT+02:00 Andres Freund <andres@anarazel.de>:

On June 14, 2017 7:53:05 PM PDT, Pavel Stehule <pavel.stehule@gmail.com>
wrote:

2017-06-14 19:49 GMT+02:00 Andres Freund <andres@anarazel.de>:

On 2017-06-14 06:05:24 +0200, Pavel Stehule wrote:

2017-06-14 5:53 GMT+02:00 Peter Eisentraut <

peter.eisentraut@2ndquadrant.com

:

On 6/13/17 17:08, Andres Freund wrote:

I wondered before if we shouldn't introduce "information only"
unenforced foreign key constraints for the catalogs. We kind

of

manually do that via oidjoins, it'd be nicer if we'd a function
rechecking fkeys, and the fkeys were in the catalog...

I don't see why we couldn't just add a full complement of primary

and

foreign key constraints (and unique constraints and perhaps some

check

constraints). The argument is that they wouldn't normally do

anything,

but they would help with documentation and browsing tools, and

they

wouldn't hurt anything.

Well, unique constraints are a bit more complicated because they rely

on

an index, and we wouldn't e.g. maintain indexes with WHERE clauses or
other expressions correctly. I'd be a bit wary of declaring such
indexes as actually being fully valid, because we have planner logic
that does planning based on various constraints now, it'd certainly

be

annoying if some "re-check constraint" type queries would actually

have

their joins optimized away or such...

These constraints can slowdown creating/dropping database objects -

mainly

temp tables.

How so?

execution RI triggers

Those would obviously bit be fired, given Peter's description?

ok

On 2017-06-14 20:02:27 -0700, Andres Freund wrote:

On June 14, 2017 7:53:05 PM PDT, Pavel Stehule <pavel.stehule@gmail.com> wrote:

2017-06-14 19:49 GMT+02:00 Andres Freund <andres@anarazel.de>:

These constraints can slowdown creating/dropping database objects -

mainly

temp tables.

How so?

execution RI triggers

Those would obviously bit be fired, given Peter's description?

Gah, stupid autocorrect. *not* be fired. Unless you mean something
else than the speed of catalog manipulations themselves, in which case I
still don't understand.

- Andres

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2017-06-15 5:06 GMT+02:00 Andres Freund <andres@anarazel.de>:

On 2017-06-14 20:02:27 -0700, Andres Freund wrote:

On June 14, 2017 7:53:05 PM PDT, Pavel Stehule <pavel.stehule@gmail.com>

wrote:

2017-06-14 19:49 GMT+02:00 Andres Freund <andres@anarazel.de>:

These constraints can slowdown creating/dropping database objects -

mainly

temp tables.

How so?

execution RI triggers

Those would obviously bit be fired, given Peter's description?

Gah, stupid autocorrect. *not* be fired. Unless you mean something
else than the speed of catalog manipulations themselves, in which case I
still don't understand.

No, just this. I missed it.

Regards

Pavel