Preserve index data in pg_statistic across REINDEX CONCURRENTLY

Statistics associated to an index got lost after running REINDEX
CONCURRENTLY, while the non-concurrent case preserves these correctly.
The concurrent and non-concurrent operations need to be consistent for
the end-user, and missing statistics would force to wait for a new
analyze to happen, which could take some time depending on the activity
of the existing autovacuum workers.  This issue is fixed by copying any
existing entries in pg_statistic associated to the old index to the new
one.  Note that this copy is already done with the data of the index in
the stats collector.

Reported-by: Fabrízio de Royes Mello
Author: Michael Paquier, Fabrízio de Royes Mello
Reviewed-by: Justin Pryzby
Discussion: https://postgr.es/m/CAFcNs+qpFPmiHd1oTXvcPdvAHicJDA9qBUSujgAhUMJyUMb+SA@mail.gmail.com
Backpatch-through: 12
This commit is contained in:
Michael Paquier
2020-11-01 21:22:07 +09:00
parent aecaa04418
commit b17ff07aa3
5 changed files with 79 additions and 0 deletions

View File

@ -1079,6 +1079,12 @@ CREATE UNIQUE INDEX concur_exprs_index_pred ON concur_exprs_tab (c1)
CREATE UNIQUE INDEX concur_exprs_index_pred_2
ON concur_exprs_tab ((1 / c1))
WHERE ('-H') >= (c2::TEXT) COLLATE "C";
ANALYZE concur_exprs_tab;
SELECT starelid::regclass, count(*) FROM pg_statistic WHERE starelid IN (
'concur_exprs_index_expr'::regclass,
'concur_exprs_index_pred'::regclass,
'concur_exprs_index_pred_2'::regclass)
GROUP BY starelid ORDER BY starelid::regclass::text;
SELECT pg_get_indexdef('concur_exprs_index_expr'::regclass);
SELECT pg_get_indexdef('concur_exprs_index_pred'::regclass);
SELECT pg_get_indexdef('concur_exprs_index_pred_2'::regclass);
@ -1091,6 +1097,12 @@ ALTER TABLE concur_exprs_tab ALTER c2 TYPE TEXT;
SELECT pg_get_indexdef('concur_exprs_index_expr'::regclass);
SELECT pg_get_indexdef('concur_exprs_index_pred'::regclass);
SELECT pg_get_indexdef('concur_exprs_index_pred_2'::regclass);
-- Statistics should remain intact.
SELECT starelid::regclass, count(*) FROM pg_statistic WHERE starelid IN (
'concur_exprs_index_expr'::regclass,
'concur_exprs_index_pred'::regclass,
'concur_exprs_index_pred_2'::regclass)
GROUP BY starelid ORDER BY starelid::regclass::text;
DROP TABLE concur_exprs_tab;
-- Temporary tables and on-commit actions, where CONCURRENTLY is ignored.