From 67dc4ccbb2e1c27da823eced66d9217a5652cbb0 Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Fri, 18 Nov 2016 12:00:00 -0500 Subject: [PATCH] Add pg_sequences view Like pg_tables, pg_views, and others, this view contains information about sequences in a way that is independent of the system catalog layout but more comprehensive than the information schema. To help implement the view, add a new internal function pg_sequence_last_value() to return the last value of a sequence. This is kept separate from pg_sequence_parameters() to separate querying run-time state from catalog-like information. Reviewed-by: Andreas Karlsson --- doc/src/sgml/catalogs.sgml | 97 ++++++++++++++++++++++++ src/backend/catalog/system_views.sql | 17 +++++ src/backend/commands/sequence.c | 49 +++++++++++- src/include/catalog/catversion.h | 2 +- src/include/catalog/pg_proc.h | 4 +- src/include/commands/sequence.h | 1 + src/test/regress/expected/rules.out | 14 ++++ src/test/regress/expected/sequence.out | 23 +++++- src/test/regress/expected/sequence_1.out | 23 +++++- src/test/regress/sql/sequence.sql | 13 +++- 10 files changed, 233 insertions(+), 10 deletions(-) diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml index bac169a19e..561e228558 100644 --- a/doc/src/sgml/catalogs.sgml +++ b/doc/src/sgml/catalogs.sgml @@ -7394,6 +7394,11 @@ security labels + + pg_sequences + sequences + + pg_settings parameter settings @@ -9135,6 +9140,98 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx + + <structname>pg_sequences</structname> + + + pg_sequences + + + + The view pg_sequences provides access to + useful information about each sequence in the database. + + + + <structname>pg_sequences</> Columns + + + + + Name + Type + References + Description + + + + + schemaname + name + pg_namespace.nspname + Name of schema containing sequence + + + sequencename + name + pg_class.relname + Name of sequence + + + sequenceowner + name + pg_authid.rolname + Name of sequence's owner + + + start_value + bigint + + Start value of the sequence + + + min_value + bigint + + Minimum value of the sequence + + + max_value + bigint + + Maximum value of the sequence + + + increment_by + bigint + + Increment value of the sequence + + + cycle + boolean + + Whether the sequence cycles + + + cache_size + bigint + + Cache size of the sequence + + + last_value + bigint + + The last sequence value written to disk. If caching is used, + this value can be greater than the last value handed out from the + sequence. Null if the sequence has not been read from yet. + + + +
+ + <structname>pg_settings</structname> diff --git a/src/backend/catalog/system_views.sql b/src/backend/catalog/system_views.sql index ada214274f..e011af122c 100644 --- a/src/backend/catalog/system_views.sql +++ b/src/backend/catalog/system_views.sql @@ -158,6 +158,23 @@ CREATE VIEW pg_indexes AS LEFT JOIN pg_tablespace T ON (T.oid = I.reltablespace) WHERE C.relkind IN ('r', 'm') AND I.relkind = 'i'; +CREATE OR REPLACE VIEW pg_sequences AS + SELECT + N.nspname AS schemaname, + C.relname AS sequencename, + pg_get_userbyid(C.relowner) AS sequenceowner, + p.start_value AS start_value, + p.minimum_value AS min_value, + p.maximum_value AS max_value, + p.increment AS increment_by, + p.cycle_option AS cycle, + p.cache_size AS cache_size, + pg_sequence_last_value(C.oid) AS last_value + FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace), + LATERAL pg_sequence_parameters(C.oid) p + WHERE NOT pg_is_other_temp_schema(N.oid) + AND relkind = 'S'; + CREATE VIEW pg_stats WITH (security_barrier) AS SELECT nspname AS schemaname, diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c index fc3a8eebce..7e37108b8d 100644 --- a/src/backend/commands/sequence.c +++ b/src/backend/commands/sequence.c @@ -1534,8 +1534,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS) { Oid relid = PG_GETARG_OID(0); TupleDesc tupdesc; - Datum values[5]; - bool isnull[5]; + Datum values[6]; + bool isnull[6]; SeqTable elm; Relation seqrel; Buffer buf; @@ -1551,7 +1551,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS) errmsg("permission denied for sequence %s", RelationGetRelationName(seqrel)))); - tupdesc = CreateTemplateTupleDesc(5, false); + tupdesc = CreateTemplateTupleDesc(6, false); TupleDescInitEntry(tupdesc, (AttrNumber) 1, "start_value", INT8OID, -1, 0); TupleDescInitEntry(tupdesc, (AttrNumber) 2, "minimum_value", @@ -1562,6 +1562,8 @@ pg_sequence_parameters(PG_FUNCTION_ARGS) INT8OID, -1, 0); TupleDescInitEntry(tupdesc, (AttrNumber) 5, "cycle_option", BOOLOID, -1, 0); + TupleDescInitEntry(tupdesc, (AttrNumber) 6, "cache_size", + INT8OID, -1, 0); BlessTupleDesc(tupdesc); @@ -1574,6 +1576,7 @@ pg_sequence_parameters(PG_FUNCTION_ARGS) values[2] = Int64GetDatum(seq->max_value); values[3] = Int64GetDatum(seq->increment_by); values[4] = BoolGetDatum(seq->is_cycled); + values[5] = Int64GetDatum(seq->cache_value); UnlockReleaseBuffer(buf); relation_close(seqrel, NoLock); @@ -1581,6 +1584,46 @@ pg_sequence_parameters(PG_FUNCTION_ARGS) return HeapTupleGetDatum(heap_form_tuple(tupdesc, values, isnull)); } +/* + * Return the last value from the sequence + * + * Note: This has a completely different meaning than lastval(). + */ +Datum +pg_sequence_last_value(PG_FUNCTION_ARGS) +{ + Oid relid = PG_GETARG_OID(0); + SeqTable elm; + Relation seqrel; + Buffer buf; + HeapTupleData seqtuple; + Form_pg_sequence seq; + bool is_called; + int64 result; + + /* open and AccessShareLock sequence */ + init_sequence(relid, &elm, &seqrel); + + if (pg_class_aclcheck(relid, GetUserId(), ACL_SELECT | ACL_USAGE) != ACLCHECK_OK) + ereport(ERROR, + (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), + errmsg("permission denied for sequence %s", + RelationGetRelationName(seqrel)))); + + seq = read_seq_tuple(elm, seqrel, &buf, &seqtuple); + + is_called = seq->is_called; + result = seq->last_value; + + UnlockReleaseBuffer(buf); + relation_close(seqrel, NoLock); + + if (is_called) + PG_RETURN_INT64(result); + else + PG_RETURN_NULL(); +} + void seq_redo(XLogReaderState *record) diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h index 880559650a..ef0386ceda 100644 --- a/src/include/catalog/catversion.h +++ b/src/include/catalog/catversion.h @@ -53,6 +53,6 @@ */ /* yyyymmddN */ -#define CATALOG_VERSION_NO 201611041 +#define CATALOG_VERSION_NO 201611181 #endif diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h index 17ec71d47e..047a1ce71c 100644 --- a/src/include/catalog/pg_proc.h +++ b/src/include/catalog/pg_proc.h @@ -1763,8 +1763,10 @@ DATA(insert OID = 1576 ( setval PGNSP PGUID 12 1 0 0 0 f f f f t f v u 2 0 20 DESCR("set sequence value"); DATA(insert OID = 1765 ( setval PGNSP PGUID 12 1 0 0 0 f f f f t f v u 3 0 20 "2205 20 16" _null_ _null_ _null_ _null_ _null_ setval3_oid _null_ _null_ _null_ )); DESCR("set sequence value and is_called status"); -DATA(insert OID = 3078 ( pg_sequence_parameters PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16}" "{i,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_)); +DATA(insert OID = 3078 ( pg_sequence_parameters PGNSP PGUID 12 1 0 0 0 f f f f t f s s 1 0 2249 "26" "{26,20,20,20,20,16,20}" "{i,o,o,o,o,o,o}" "{sequence_oid,start_value,minimum_value,maximum_value,increment,cycle_option,cache_size}" _null_ _null_ pg_sequence_parameters _null_ _null_ _null_)); DESCR("sequence parameters, for use by information schema"); +DATA(insert OID = 4032 ( pg_sequence_last_value PGNSP PGUID 12 1 0 0 0 f f f f t f v u 1 0 20 "2205" _null_ _null_ _null_ _null_ _null_ pg_sequence_last_value _null_ _null_ _null_ )); +DESCR("sequence last value"); DATA(insert OID = 1579 ( varbit_in PGNSP PGUID 12 1 0 0 0 f f f f t f i s 3 0 1562 "2275 26 23" _null_ _null_ _null_ _null_ _null_ varbit_in _null_ _null_ _null_ )); DESCR("I/O"); diff --git a/src/include/commands/sequence.h b/src/include/commands/sequence.h index 392a626508..6695bbe4c7 100644 --- a/src/include/commands/sequence.h +++ b/src/include/commands/sequence.h @@ -73,6 +73,7 @@ extern Datum setval3_oid(PG_FUNCTION_ARGS); extern Datum lastval(PG_FUNCTION_ARGS); extern Datum pg_sequence_parameters(PG_FUNCTION_ARGS); +extern Datum pg_sequence_last_value(PG_FUNCTION_ARGS); extern ObjectAddress DefineSequence(ParseState *pstate, CreateSeqStmt *stmt); extern ObjectAddress AlterSequence(ParseState *pstate, AlterSeqStmt *stmt); diff --git a/src/test/regress/expected/rules.out b/src/test/regress/expected/rules.out index 5e2962c681..031e8c2ef5 100644 --- a/src/test/regress/expected/rules.out +++ b/src/test/regress/expected/rules.out @@ -1615,6 +1615,20 @@ UNION ALL l.label FROM (pg_shseclabel l JOIN pg_authid rol ON (((l.classoid = rol.tableoid) AND (l.objoid = rol.oid)))); +pg_sequences| SELECT n.nspname AS schemaname, + c.relname AS sequencename, + pg_get_userbyid(c.relowner) AS sequenceowner, + p.start_value, + p.minimum_value AS min_value, + p.maximum_value AS max_value, + p.increment AS increment_by, + p.cycle_option AS cycle, + p.cache_size, + pg_sequence_last_value((c.oid)::regclass) AS last_value + FROM (pg_class c + LEFT JOIN pg_namespace n ON ((n.oid = c.relnamespace))), + LATERAL pg_sequence_parameters(c.oid) p(start_value, minimum_value, maximum_value, increment, cycle_option, cache_size) + WHERE ((NOT pg_is_other_temp_schema(n.oid)) AND (c.relkind = 'S'::"char")); pg_settings| SELECT a.name, a.setting, a.unit, diff --git a/src/test/regress/expected/sequence.out b/src/test/regress/expected/sequence.out index 4ffbe92ab3..c5413e09f3 100644 --- a/src/test/regress/expected/sequence.out +++ b/src/test/regress/expected/sequence.out @@ -300,20 +300,39 @@ SELECT nextval('sequence_test2'); 5 (1 row) +CREATE SEQUENCE sequence_test3; -- not read from, to test is_called -- Information schema SELECT * FROM information_schema.sequences WHERE sequence_name IN - ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq', + ('sequence_test2', 'sequence_test3', 'serialtest2_f2_seq', 'serialtest2_f3_seq', 'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq') ORDER BY sequence_name ASC; sequence_catalog | sequence_schema | sequence_name | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value | maximum_value | increment | cycle_option ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+-------------- regression | public | sequence_test2 | bigint | 64 | 2 | 0 | 32 | 5 | 36 | 4 | YES + regression | public | sequence_test3 | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f2_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f3_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f4_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f5_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f6_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO -(6 rows) +(7 rows) + +SELECT schemaname, sequencename, start_value, min_value, max_value, increment_by, cycle, cache_size, last_value +FROM pg_sequences +WHERE sequencename IN + ('sequence_test2', 'sequence_test3', 'serialtest2_f2_seq', 'serialtest2_f3_seq', + 'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq') + ORDER BY sequencename ASC; + schemaname | sequencename | start_value | min_value | max_value | increment_by | cycle | cache_size | last_value +------------+--------------------+-------------+-----------+---------------------+--------------+-------+------------+------------ + public | sequence_test2 | 32 | 5 | 36 | 4 | t | 1 | 5 + public | sequence_test3 | 1 | 1 | 9223372036854775807 | 1 | f | 1 | + public | serialtest2_f2_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f3_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f4_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f5_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f6_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 +(7 rows) -- Test comments COMMENT ON SEQUENCE asdf IS 'won''t work'; diff --git a/src/test/regress/expected/sequence_1.out b/src/test/regress/expected/sequence_1.out index 05da2bf1ad..8164244927 100644 --- a/src/test/regress/expected/sequence_1.out +++ b/src/test/regress/expected/sequence_1.out @@ -300,20 +300,39 @@ SELECT nextval('sequence_test2'); 5 (1 row) +CREATE SEQUENCE sequence_test3; -- not read from, to test is_called -- Information schema SELECT * FROM information_schema.sequences WHERE sequence_name IN - ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq', + ('sequence_test2', 'sequence_test3', 'serialtest2_f2_seq', 'serialtest2_f3_seq', 'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq') ORDER BY sequence_name ASC; sequence_catalog | sequence_schema | sequence_name | data_type | numeric_precision | numeric_precision_radix | numeric_scale | start_value | minimum_value | maximum_value | increment | cycle_option ------------------+-----------------+--------------------+-----------+-------------------+-------------------------+---------------+-------------+---------------+---------------------+-----------+-------------- regression | public | sequence_test2 | bigint | 64 | 2 | 0 | 32 | 5 | 36 | 4 | YES + regression | public | sequence_test3 | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f2_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f3_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f4_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f5_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO regression | public | serialtest2_f6_seq | bigint | 64 | 2 | 0 | 1 | 1 | 9223372036854775807 | 1 | NO -(6 rows) +(7 rows) + +SELECT schemaname, sequencename, start_value, min_value, max_value, increment_by, cycle, cache_size, last_value +FROM pg_sequences +WHERE sequencename IN + ('sequence_test2', 'sequence_test3', 'serialtest2_f2_seq', 'serialtest2_f3_seq', + 'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq') + ORDER BY sequencename ASC; + schemaname | sequencename | start_value | min_value | max_value | increment_by | cycle | cache_size | last_value +------------+--------------------+-------------+-----------+---------------------+--------------+-------+------------+------------ + public | sequence_test2 | 32 | 5 | 36 | 4 | t | 1 | 5 + public | sequence_test3 | 1 | 1 | 9223372036854775807 | 1 | f | 1 | + public | serialtest2_f2_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f3_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f4_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f5_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 + public | serialtest2_f6_seq | 1 | 1 | 9223372036854775807 | 1 | f | 1 | 2 +(7 rows) -- Test comments COMMENT ON SEQUENCE asdf IS 'won''t work'; diff --git a/src/test/regress/sql/sequence.sql b/src/test/regress/sql/sequence.sql index 98a2e7db36..e2b6b63393 100644 --- a/src/test/regress/sql/sequence.sql +++ b/src/test/regress/sql/sequence.sql @@ -138,12 +138,23 @@ SELECT nextval('sequence_test2'); SELECT nextval('sequence_test2'); SELECT nextval('sequence_test2'); + +CREATE SEQUENCE sequence_test3; -- not read from, to test is_called + + -- Information schema SELECT * FROM information_schema.sequences WHERE sequence_name IN - ('sequence_test2', 'serialtest2_f2_seq', 'serialtest2_f3_seq', + ('sequence_test2', 'sequence_test3', 'serialtest2_f2_seq', 'serialtest2_f3_seq', 'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq') ORDER BY sequence_name ASC; +SELECT schemaname, sequencename, start_value, min_value, max_value, increment_by, cycle, cache_size, last_value +FROM pg_sequences +WHERE sequencename IN + ('sequence_test2', 'sequence_test3', 'serialtest2_f2_seq', 'serialtest2_f3_seq', + 'serialtest2_f4_seq', 'serialtest2_f5_seq', 'serialtest2_f6_seq') + ORDER BY sequencename ASC; + -- Test comments COMMENT ON SEQUENCE asdf IS 'won''t work'; COMMENT ON SEQUENCE sequence_test2 IS 'will work';