From 8493831385814c4f22b1d5b5d8a9227a2eb82712 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Wed, 10 Feb 2021 13:09:09 +0900 Subject: [PATCH] Preserve pg_attribute.attstattarget across REINDEX CONCURRENTLY For an index, attstattarget can be updated using ALTER INDEX SET STATISTICS. This data was lost on the new index after REINDEX CONCURRENTLY. The update of this field is done when the old and new indexes are swapped to make the fix back-patchable. Another approach we could look after in the long-term is to change index_create() to pass the wanted values of attstattarget when creating the new relation, but, as this would cause an ABI breakage this can be done only on HEAD. Reported-by: Ronan Dunklau Author: Michael Paquier Reviewed-by: Ronan Dunklau, Tomas Vondra Discussion: https://postgr.es/m/16628084.uLZWGnKmhe@laptop-ronand Backpatch-through: 12 --- src/backend/catalog/index.c | 56 ++++++++++++++++++++++ src/backend/utils/cache/lsyscache.c | 27 +++++++++++ src/include/utils/lsyscache.h | 1 + src/test/regress/expected/create_index.out | 15 ++++++ src/test/regress/sql/create_index.sql | 8 ++++ 5 files changed, 107 insertions(+) diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c index 453b6e8793..b9eed8ec38 100644 --- a/src/backend/catalog/index.c +++ b/src/backend/catalog/index.c @@ -1728,6 +1728,62 @@ index_concurrently_swap(Oid newIndexId, Oid oldIndexId, const char *oldName) /* Copy data of pg_statistic from the old index to the new one */ CopyStatistics(oldIndexId, newIndexId); + /* Copy pg_attribute.attstattarget for each index attribute */ + { + HeapTuple attrTuple; + Relation pg_attribute; + SysScanDesc scan; + ScanKeyData key[1]; + + pg_attribute = table_open(AttributeRelationId, RowExclusiveLock); + ScanKeyInit(&key[0], + Anum_pg_attribute_attrelid, + BTEqualStrategyNumber, F_OIDEQ, + ObjectIdGetDatum(newIndexId)); + scan = systable_beginscan(pg_attribute, AttributeRelidNumIndexId, + true, NULL, 1, key); + + while (HeapTupleIsValid((attrTuple = systable_getnext(scan)))) + { + Form_pg_attribute att = (Form_pg_attribute) GETSTRUCT(attrTuple); + Datum repl_val[Natts_pg_attribute]; + bool repl_null[Natts_pg_attribute]; + bool repl_repl[Natts_pg_attribute]; + int attstattarget; + HeapTuple newTuple; + + /* Ignore dropped columns */ + if (att->attisdropped) + continue; + + /* + * Get attstattarget from the old index and refresh the new value. + */ + attstattarget = get_attstattarget(oldIndexId, att->attnum); + + /* no need for a refresh if both match */ + if (attstattarget == att->attstattarget) + continue; + + memset(repl_val, 0, sizeof(repl_val)); + memset(repl_null, false, sizeof(repl_null)); + memset(repl_repl, false, sizeof(repl_repl)); + + repl_repl[Anum_pg_attribute_attstattarget - 1] = true; + repl_val[Anum_pg_attribute_attstattarget - 1] = Int32GetDatum(attstattarget); + + newTuple = heap_modify_tuple(attrTuple, + RelationGetDescr(pg_attribute), + repl_val, repl_null, repl_repl); + CatalogTupleUpdate(pg_attribute, &newTuple->t_self, newTuple); + + heap_freetuple(newTuple); + } + + systable_endscan(scan); + table_close(pg_attribute, RowExclusiveLock); + } + /* Close relations */ table_close(pg_class, RowExclusiveLock); table_close(pg_index, RowExclusiveLock); diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c index 140339073b..3303c31e57 100644 --- a/src/backend/utils/cache/lsyscache.c +++ b/src/backend/utils/cache/lsyscache.c @@ -871,6 +871,33 @@ get_attnum(Oid relid, const char *attname) return InvalidAttrNumber; } +/* + * get_attstattarget + * + * Given the relation id and the attribute number, + * return the "attstattarget" field from the attribute relation. + * + * Errors if not found. + */ +int +get_attstattarget(Oid relid, AttrNumber attnum) +{ + HeapTuple tp; + Form_pg_attribute att_tup; + int result; + + tp = SearchSysCache2(ATTNUM, + ObjectIdGetDatum(relid), + Int16GetDatum(attnum)); + if (!HeapTupleIsValid(tp)) + elog(ERROR, "cache lookup failed for attribute %d of relation %u", + attnum, relid); + att_tup = (Form_pg_attribute) GETSTRUCT(tp); + result = att_tup->attstattarget; + ReleaseSysCache(tp); + return result; +} + /* * get_attgenerated * diff --git a/src/include/utils/lsyscache.h b/src/include/utils/lsyscache.h index fecfe1f4f6..ee35686a66 100644 --- a/src/include/utils/lsyscache.h +++ b/src/include/utils/lsyscache.h @@ -87,6 +87,7 @@ extern Oid get_opfamily_proc(Oid opfamily, Oid lefttype, Oid righttype, int16 procnum); extern char *get_attname(Oid relid, AttrNumber attnum, bool missing_ok); extern AttrNumber get_attnum(Oid relid, const char *attname); +extern int get_attstattarget(Oid relid, AttrNumber attnum); extern char get_attgenerated(Oid relid, AttrNumber attnum); extern Oid get_atttype(Oid relid, AttrNumber attnum); extern void get_atttypetypmodcoll(Oid relid, AttrNumber attnum, diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out index 49aa5780a8..2cd07f64dd 100644 --- a/src/test/regress/expected/create_index.out +++ b/src/test/regress/expected/create_index.out @@ -2419,6 +2419,7 @@ 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"; +ALTER INDEX concur_exprs_index_expr ALTER COLUMN 1 SET STATISTICS 100; ANALYZE concur_exprs_tab; SELECT starelid::regclass, count(*) FROM pg_statistic WHERE starelid IN ( 'concur_exprs_index_expr'::regclass, @@ -2498,6 +2499,20 @@ SELECT starelid::regclass, count(*) FROM pg_statistic WHERE starelid IN ( concur_exprs_index_expr | 1 (1 row) +-- attstattarget should remain intact +SELECT attrelid::regclass, attnum, attstattarget + FROM pg_attribute WHERE attrelid IN ( + 'concur_exprs_index_expr'::regclass, + 'concur_exprs_index_pred'::regclass, + 'concur_exprs_index_pred_2'::regclass) + ORDER BY 'concur_exprs_index_expr'::regclass::text, attnum; + attrelid | attnum | attstattarget +---------------------------+--------+--------------- + concur_exprs_index_expr | 1 | 100 + concur_exprs_index_pred | 1 | -1 + concur_exprs_index_pred_2 | 1 | -1 +(3 rows) + DROP TABLE concur_exprs_tab; -- Temporary tables and on-commit actions, where CONCURRENTLY is ignored. -- ON COMMIT PRESERVE ROWS, the default. diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql index 344c648485..c130b86c02 100644 --- a/src/test/regress/sql/create_index.sql +++ b/src/test/regress/sql/create_index.sql @@ -1003,6 +1003,7 @@ 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"; +ALTER INDEX concur_exprs_index_expr ALTER COLUMN 1 SET STATISTICS 100; ANALYZE concur_exprs_tab; SELECT starelid::regclass, count(*) FROM pg_statistic WHERE starelid IN ( 'concur_exprs_index_expr'::regclass, @@ -1027,6 +1028,13 @@ SELECT starelid::regclass, count(*) FROM pg_statistic WHERE starelid IN ( 'concur_exprs_index_pred'::regclass, 'concur_exprs_index_pred_2'::regclass) GROUP BY starelid ORDER BY starelid::regclass::text; +-- attstattarget should remain intact +SELECT attrelid::regclass, attnum, attstattarget + FROM pg_attribute WHERE attrelid IN ( + 'concur_exprs_index_expr'::regclass, + 'concur_exprs_index_pred'::regclass, + 'concur_exprs_index_pred_2'::regclass) + ORDER BY 'concur_exprs_index_expr'::regclass::text, attnum; DROP TABLE concur_exprs_tab; -- Temporary tables and on-commit actions, where CONCURRENTLY is ignored.