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| author | Peter Eisentraut <peter_e@gmx.net> | 2016-11-18 12:00:00 -0500 |
|---|---|---|
| committer | Peter Eisentraut <peter_e@gmx.net> | 2016-11-18 14:59:03 -0500 |
| commit | 67dc4ccbb2e1c27da823eced66d9217a5652cbb0 (patch) | |
| tree | a761b8c65e08543c96680c1f0a26410b2f5bb93e /src/backend/commands/sequence.c | |
| parent | 8f91f323b4feef0371cd3db51be3007e44abd5e8 (diff) | |
| download | postgresql-67dc4ccbb2e1c27da823eced66d9217a5652cbb0.tar.gz postgresql-67dc4ccbb2e1c27da823eced66d9217a5652cbb0.zip | |
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 <andreas@proxel.se>
Diffstat (limited to 'src/backend/commands/sequence.c')
| -rw-r--r-- | src/backend/commands/sequence.c | 49 |
1 files changed, 46 insertions, 3 deletions
diff --git a/src/backend/commands/sequence.c b/src/backend/commands/sequence.c index fc3a8eebce3..7e37108b8d6 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) |