Re: [HACKERS] proposal: schema variables
| От | Pavel Stehule |
|---|---|
| Тема | Re: [HACKERS] proposal: schema variables |
| Дата | |
| Msg-id | CAFj8pRA6YWwV=sZj5iSgDUixr-S+u9W2+v0BJqqxHQDXS2oZww@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: [HACKERS] proposal: schema variables (Pavel Stehule <pavel.stehule@gmail.com>) |
| Ответы |
Re: [HACKERS] proposal: schema variables
|
| Список | pgsql-hackers |
Hi
2018-02-07 7:34 GMT+01:00 Pavel Stehule <pavel.stehule@gmail.com>:
Hiupdated patch with your changes in documentation and pg_dump (initial) supportMain issue of this patch is storage. We can reuse local buffers used for temp tables. But it does allocation by 8KB and it creates temp files for every object. That is too big overhead. Storing just in session memory is too simple - then there should be lot of new code used, when variable will be dropped.I have ideas how to allow work with mix of scalar and composite types - so it will be next step of this prototype.RegardsPavel
new update - rebased, + some initial support for composite values on right side and custom types, arrays are supported too.
omega=# CREATE VARIABLE xx AS (a int, b numeric);
CREATE VARIABLE
omega=# LET xx = (10, 20)::xx;
LET
omega=# SELECT xx;
+---------+
| xx |
+---------+
| (10,20) |
+---------+
(1 row)
omega=# SELECT xx.a + xx.b;
+----------+
| ?column? |
+----------+
| 30 |
+----------+
(1 row)
omega=# \d xx
schema variable "public.xx"
+--------+---------+
| Column | Type |
+--------+---------+
| a | integer |
| b | numeric |
+--------+---------+
omega=# CREATE VARIABLE xx AS (a int, b numeric);
CREATE VARIABLE
omega=# LET xx = (10, 20)::xx;
LET
omega=# SELECT xx;
+---------+
| xx |
+---------+
| (10,20) |
+---------+
(1 row)
omega=# SELECT xx.a + xx.b;
+----------+
| ?column? |
+----------+
| 30 |
+----------+
(1 row)
omega=# \d xx
schema variable "public.xx"
+--------+---------+
| Column | Type |
+--------+---------+
| a | integer |
| b | numeric |
+--------+---------+
Regards
Pavel
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