Re: proposal: schema variables

Tsunakawa, Takayuki <tsunakawa.takay@jp.fujitsu.com>

From: "Tsunakawa, Takayuki" <tsunakawa.takay@jp.fujitsu.com>

To: 'Pavel Stehule' <pavel.stehule@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>

Date: 2017-10-27T05:47:29Z

Lists: pgsql-hackers, pgsql-performance

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Move WAL sequence code into its own file
- a87987cafca6 19 (unreleased) cited
Add ExplainState argument to pg_plan_query() and planner().
- c83ac02ec730 19 (unreleased) cited
Don't include access/htup_details.h in executor/tuptable.h
- 1a8b5b11e48a 19 (unreleased) cited
Refactor to avoid code duplication in transformPLAssignStmt.
- b0fb2c6aa5a4 19 (unreleased) cited
Avoid including commands/dbcommands.h in so many places
- 325fc0ab14d1 19 (unreleased) cited
Restrict psql meta-commands in plain-text dumps.
- 71ea0d679543 19 (unreleased) cited
Split func.sgml into more manageable pieces
- 4e23c9ef65ac 19 (unreleased) cited
Fix squashing algorithm for query texts
- 0f65f3eec478 18.0 cited
EXPLAIN: Always use two fractional digits for row counts.
- 95dbd827f2ed 18.0 cited
Preliminary refactoring of plpgsql expression construction.
- a654af21ae52 18.0 cited
plpgsql: pure parser and reentrant scanner
- 7b27f5fd36cb 18.0 cited
Add some sanity checks in executor for query ID reporting
- 24f520594809 18.0 cited
Fix misleading error message context
- 4af123ad45bd 18.0 cited
Add macros for looping through a List without a ListCell.
- 14dd0f27d7cd 17.0 cited

From: pgsql-hackers-owner@postgresql.org
> [mailto:pgsql-hackers-owner@postgresql.org] On Behalf Of Pavel Stehule
> I propose a  new database object - a variable. The variable is persistent
> object, that holds unshared session based not transactional in memory value
> of any type. Like variables in any other languages. The persistence is
> required for possibility to do static checks, but can be limited to session
> - the variables can be temporal.
> 
> 
> My proposal is related to session variables from Sybase, MSSQL or MySQL
> (based on prefix usage @ or @@), or package variables from Oracle (access
> is controlled by scope), or schema variables from DB2. Any design is coming
> from different sources, traditions and has some advantages or disadvantages.
> The base of my proposal is usage schema variables as session variables for
> stored procedures. It should to help to people who try to port complex
> projects to PostgreSQL from other databases.

Very interesting.  I hope I could join the review and testing.

How do you think this would contribute to easing the port of Oracle PL/SQL procedures?  Would the combination of orafce and this feature promote auto-translation of PL/SQL procedures?  I'm curious what will be the major road blocks after adding the schema variable.

Regards
Takayuki Tsunakawa