Re: proposal: schema variables - doc

Pavel Stehule <pavel.stehule@gmail.com>

From: Pavel Stehule <pavel.stehule@gmail.com>

To: Erik Rijkers <er@xs4all.nl>

Cc: Michael Paquier <michael@paquier.xyz>, Zhihong Yu <zyu@yugabyte.com>, Amit Kapila <amit.kapila16@gmail.com>, DUVAL REMI <REMI.DUVAL@cheops.fr>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>

Date: 2021-03-25T08:05:43Z

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

Attachments

schema-variables-20210325.patch.gz (application/gzip) patch

Hi



po 22. 3. 2021 v 10:47 odesílatel Pavel Stehule <pavel.stehule@gmail.com>
napsal:

> Hi
>
> st 17. 3. 2021 v 13:05 odesílatel Erik Rijkers <er@xs4all.nl> napsal:
>
>>
>> > On 2021.03.13. 07:01 Pavel Stehule <pavel.stehule@gmail.com> wrote:
>> > Hi
>> > fresh rebase
>> > [schema-variables-20210313.patch.gz]
>>
>>
>> Hi Pavel,
>>
>> I notice that the phrase 'schema variable' is not in the index at the end
>> ('bookindex.html').  Not good.
>>
>> It is also not in the index at the front of the manual - also not good.
>>
>> Maybe these two (front and back index) can be added?
>>
>
> I inserted new indexterm "schema variable", and now this part of
> bookindex.html looks like:
>
> schema variablealtering, ALTER VARIABLEchanging, LETdefining, CREATE
> VARIABLEdescription, Descriptionremoving, DROP VARIABLE
>
>
>
>>
>> If a user searches the pdf, the first occurrence he finds is at:
>>
>>   43.13.2.4. Global variables and constants
>>   (in itself that occurrence/mention is all right, but is should not be
>> the first find, I think)
>>
>> (I think there was in earlier versions of the patch an entry in the
>> 'contents', i.e., at the front of the manual).  I think it would be good to
>> have it in the front-index, pointing to either LET or CREATE VARIABLE, or
>> maybe even to a small introductory paragraph somewhere else (again, I seem
>> to remember that there was one in an earlier patch version).
>>
>
>
> I wrote new section to "advanced features" about schema variables
>
>
>>
>>
>> Of the new commands that this patch brings, 'LET' is the most immediately
>> illuminating for a user (even when a CREATE VARIABLE has to be done first.
>> There is an entry 'LET' in the index (good), but it would be better if that
>> with LET-entry too the phrase 'schema variable' occurred.  (I don't know if
>> that's possible)
>>
>>
>> Then, in the CREATE VARIABLE paragraphs it says
>>    'Changing a schema variable is non-transactional by default.'
>>
>> I think that, unless there exists a mode where schema vars can be made
>> transactional, 'by default' should be deleted (and there is no such
>> 'transactional mode' for schema variables, is there?).  The 'Description'
>> also has such a 'By default' which is better removed for the same reason.
>>
>
> fixed
>
>
>>
>> In the CREATE VARIABLE page the example is:
>>
>> CREATE VARIABLE var1 AS integer;
>> SELECT var1;
>>
>> I suggest to make that
>>
>> CREATE VARIABLE var1 AS date;
>> LET var1 = (select current_date);
>> SELECT var1;
>>
>> So that the example immediately shows an application of functionality.
>>
>
> done
>
> Thank you for the documentation review.
>
> Updated patch attached
>
> Regards
>
> Pavel
>
>
fresh update with merged Eric's changes in documentation

Regards

Pavel


>
>>
>> Thanks,
>>
>> Erik Rijkers
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> >
>> > Pavel
>>
>