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Rework design of functions in pg_walinspect

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This commit reworks a bit the set-returning functions of pg_walinspect,
making them more flexible regarding their end LSN:
- pg_get_wal_records_info()
- pg_get_wal_stats()
- pg_get_wal_block_info()

The end LSNs given to these functions is now handled so as a value
higher than the current LSN of the cluster (insert LSN for a primary, or
replay LSN for a standby) does not raise an error, giving more
flexibility to monitoring queries.  Instead, the functions return
results up to the current LSN, as found at the beginning of each
function call.

As an effect of that, pg_get_wal_records_info_till_end_of_wal() and
pg_get_wal_stats_till_end_of_wal() are now removed from 1.1, as the
existing, equivalent functions are able to offer the same
possibilities.

Author: Bharath Rupireddy
Discussion: https://postgr.es/m/CALj2ACU0_q-o4DSweyaW9NO1KBx-QkN6G_OzYQvpjf3CZVASkg@mail.gmail.com
This commit is contained in:
Michael Paquier
2023-03-14 20:13:02 +09:00
parent d5d574146d
commit 5c1b662807
7 changed files with 185 additions and 208 deletions
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46
contrib/pg_walinspect/expected/oldextversions.out
View File

@ -1,5 +1,7 @@
-- test old extension version entry points
CREATE EXTENSION pg_walinspect WITH VERSION '1.0';
-- Mask DETAIL messages as these could refer to current LSN positions.
\set VERBOSITY terse
-- List what version 1.0 contains
\dx+ pg_walinspect
Objects in extension "pg_walinspect"
@ -12,19 +14,51 @@ CREATE EXTENSION pg_walinspect WITH VERSION '1.0';
function pg_get_wal_stats_till_end_of_wal(pg_lsn,boolean)
(5 rows)
-- Make sure checkpoints don't interfere with the test.
SELECT 'init' FROM pg_create_physical_replication_slot('regress_pg_walinspect_slot', true, false);
?column?
----------
init
(1 row)
CREATE TABLE sample_tbl(col1 int, col2 int);
SELECT pg_current_wal_lsn() AS wal_lsn1 \gset
INSERT INTO sample_tbl SELECT * FROM generate_series(1, 2);
-- Check bounds for these past functions.
SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info_till_end_of_wal(:'wal_lsn1');
ok
----
t
(1 row)
SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats_till_end_of_wal(:'wal_lsn1');
ok
----
t
(1 row)
SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_records_info_till_end_of_wal('FFFFFFFF/FFFFFFFF');
ERROR: WAL start LSN must be less than current LSN
SELECT COUNT(*) >= 1 AS ok FROM pg_get_wal_stats_till_end_of_wal('FFFFFFFF/FFFFFFFF');
ERROR: WAL start LSN must be less than current LSN
-- Move to new version 1.1
ALTER EXTENSION pg_walinspect UPDATE TO '1.1';
-- List what version 1.1 contains
\dx+ pg_walinspect
Objects in extension "pg_walinspect"
Object description
-----------------------------------------------------------
Objects in extension "pg_walinspect"
Object description
--------------------------------------------------
function pg_get_wal_block_info(pg_lsn,pg_lsn)
function pg_get_wal_record_info(pg_lsn)
function pg_get_wal_records_info(pg_lsn,pg_lsn)
function pg_get_wal_records_info_till_end_of_wal(pg_lsn)
function pg_get_wal_stats(pg_lsn,pg_lsn,boolean)
function pg_get_wal_stats_till_end_of_wal(pg_lsn,boolean)
(6 rows)
(4 rows)
SELECT pg_drop_replication_slot('regress_pg_walinspect_slot');
pg_drop_replication_slot
--------------------------
(1 row)
DROP TABLE sample_tbl;
DROP EXTENSION pg_walinspect;

44
contrib/pg_walinspect/expected/pg_walinspect.out
View File

@ -36,25 +36,33 @@ SELECT * FROM pg_get_wal_block_info(:'wal_lsn2', :'wal_lsn1');
ERROR: WAL start LSN must be less than end LSN
-- LSNs with the highest value possible.
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_record_info('FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future input LSN
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_records_info_till_end_of_wal('FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future start LSN
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_stats_till_end_of_wal('FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future start LSN
-- failures with end LSNs
ERROR: WAL input LSN must be less than current LSN
-- Success with end LSNs.
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future end LSN
ok
----
t
(1 row)
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_stats(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future end LSN
ok
----
t
(1 row)
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_block_info(:'wal_lsn1', 'FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future end LSN
ok
----
t
(1 row)
-- failures with start LSNs
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_records_info('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future start LSN
ERROR: WAL start LSN must be less than current LSN
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_stats('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future start LSN
ERROR: WAL start LSN must be less than current LSN
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_block_info('FFFFFFFF/FFFFFFFE', 'FFFFFFFF/FFFFFFFF');
ERROR: cannot accept future start LSN
ERROR: WAL start LSN must be less than current LSN
-- ===================================================================
-- Tests for all function executions
-- ===================================================================
@ -64,18 +72,6 @@ SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_record_info(:'wal_lsn1');
t
(1 row)
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_records_info_till_end_of_wal(:'wal_lsn1');
ok
----
t
(1 row)
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_stats_till_end_of_wal(:'wal_lsn1');
ok
----
t
(1 row)
SELECT COUNT(*) >= 0 AS ok FROM pg_get_wal_records_info(:'wal_lsn1', :'wal_lsn2');
ok
----