public inbox for [email protected]
help / color / mirror / Atom feedFrom: jian he <[email protected]>
To: Tom Lane <[email protected]>
Cc: PostgreSQL-development <[email protected]>
Subject: Re: support fast default for domain with constraints
Date: Thu, 6 Mar 2025 21:53:40 +0800
Message-ID: <CACJufxECb4nVjssRPknepNmqF2CR0ycPzTmJZPxoWYK4JD-mFQ@mail.gmail.com> (raw)
In-Reply-To: <CACJufxHtbn6pUPt8RRXv8BAFX67K5gyqR5SGwu8P1nSEF=ts9g@mail.gmail.com>
References: <CACJufxE_+iZBR1i49k_AHigppPwLTJi6km8NOsC7FWvKdEmmXg@mail.gmail.com>
<[email protected]>
<CACJufxGZqTUqOCmwVveq4TGG6UXrMnODkMw7x5LV4DM4RkNRcw@mail.gmail.com>
<CACJufxHtbn6pUPt8RRXv8BAFX67K5gyqR5SGwu8P1nSEF=ts9g@mail.gmail.com>
On Thu, Mar 6, 2025 at 11:04 AM jian he <[email protected]> wrote:
>
> hi.
>
> rearrange the patch.
> v3-0001 and v3-0002 is preparare patches.
> v3-0001 add function: ExecPrepareExprSafe and ExecInitExprSafe.
> v3-0002 add function: DomainHaveVolatileConstraints
>
i actually do need DomainHaveVolatileConstraints
for virtual generated columns over domain with constraints in [1],
which I am working on.
for example:
create domain d1 as int check(value > random(min=>11::int, max=>12));
create domain d2 as int check(value > 12);
create table t(a int);
insert into t select g from generate_series(1, 10) g;
----we do need table rewrite in phase 3.
alter table t add column b d1 generated always as (a+11) virtual;
--we can only do table scan in phase 3.
alter table t add column c d2 generated always as (a + 12) virtual;
Generally, table rewrite is more expensive than table scan.
In the above case, if domain constraints are not volatile, table scan
should be fine.
[1]: https://postgr.es/m/CACJufxHArQysbDkWFmvK+D1TPHQWWTxWN15cMuUaTYX3xhQXgg@mail.gmail.com
view thread (13+ messages) latest in thread
reply
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: [email protected]
Cc: [email protected], [email protected]
Subject: Re: support fast default for domain with constraints
In-Reply-To: <CACJufxECb4nVjssRPknepNmqF2CR0ycPzTmJZPxoWYK4JD-mFQ@mail.gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox