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Add pg_sequence system catalog
Move sequence metadata (start, increment, etc.) into a proper system catalog instead of storing it in the sequence heap object. This separates the metadata from the sequence data. Sequence metadata is now operated on transactionally by DDL commands, whereas previously rollbacks of sequence-related DDL commands would be ignored. Reviewed-by: Andreas Karlsson <andreas@proxel.se>
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19 files changed

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‎doc/src/sgml/catalogs.sgml‎

Lines changed: 87 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -260,6 +260,11 @@
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<entry>security labels on database objects</entry>
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</row>
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<row>
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<entry><link linkend="catalog-pg-sequence"><structname>pg_sequence</structname></link></entry>
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<entry>information about sequences</entry>
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</row>
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<row>
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<entry><link linkend="catalog-pg-shdepend"><structname>pg_shdepend</structname></link></entry>
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<entry>dependencies on shared objects</entry>
@@ -1546,7 +1551,8 @@
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The catalog <structname>pg_class</structname> catalogs tables and most
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everything else that has columns or is otherwise similar to a
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table. This includes indexes (but see also
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<structname>pg_index</structname>), sequences, views, materialized
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<structname>pg_index</structname>), sequences (but see also
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<structname>pg_sequence</structname>), views, materialized
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views, composite types, and TOAST tables; see <structfield>relkind</>.
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Below, when we mean all of these
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kinds of objects we speak of <quote>relations</quote>. Not all
@@ -5587,6 +5593,86 @@
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</table>
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</sect1>
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<sect1 id="catalog-pg-sequence">
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<title><structname>pg_sequence</structname></title>
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<indexterm zone="catalog-pg-sequence">
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<primary>pg_sequence</primary>
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</indexterm>
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<para>
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The catalog <structname>pg_sequence</structname> contains information about
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sequences. Some of the information about sequences, such as the name and
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the schema, is in <structname>pg_class</structname>.
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</para>
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<table>
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<title><structname>pg_sequence</> Columns</title>
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<tgroup cols="4">
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<thead>
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<row>
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<entry>Name</entry>
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<entry>Type</entry>
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<entry>References</entry>
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<entry>Description</entry>
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</row>
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</thead>
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<tbody>
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<row>
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<entry><structfield>seqrelid</structfield></entry>
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<entry><type>oid</type></entry>
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<entry><literal><link linkend="catalog-pg-class"><structname>pg_class</structname></link>.oid</literal></entry>
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<entry>The OID of the <structname>pg_class</> entry for this sequence</entry>
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</row>
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<row>
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<entry><structfield>seqstart</structfield></entry>
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<entry><type>int8</type></entry>
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<entry></entry>
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<entry>Start value of the sequence</entry>
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</row>
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<row>
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<entry><structfield>seqincrement</structfield></entry>
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<entry><type>int8</type></entry>
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<entry></entry>
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<entry>Increment value of the sequence</entry>
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</row>
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<row>
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<entry><structfield>seqmax</structfield></entry>
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<entry><type>int8</type></entry>
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<entry></entry>
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<entry>Maximum value of the sequence</entry>
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</row>
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<row>
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<entry><structfield>seqmin</structfield></entry>
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<entry><type>int8</type></entry>
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<entry></entry>
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<entry>Minimum value of the sequence</entry>
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</row>
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<row>
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<entry><structfield>seqcache</structfield></entry>
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<entry><type>int8</type></entry>
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<entry></entry>
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<entry>Cache size of the sequence</entry>
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</row>
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<row>
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<entry><structfield>seqcycle</structfield></entry>
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<entry><type>bool</type></entry>
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<entry></entry>
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<entry>Whether the sequence cycles</entry>
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</row>
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</tbody>
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</tgroup>
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</table>
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</sect1>
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<sect1 id="catalog-pg-shdepend">
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<title><structname>pg_shdepend</structname></title>
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‎src/backend/catalog/Makefile‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -42,6 +42,7 @@ POSTGRES_BKI_SRCS = $(addprefix $(top_srcdir)/src/include/catalog/,\
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pg_foreign_table.h pg_policy.h pg_replication_origin.h \
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pg_default_acl.h pg_init_privs.h pg_seclabel.h pg_shseclabel.h \
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pg_collation.h pg_partitioned_table.h pg_range.h pg_transform.h \
45+
pg_sequence.h \
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toasting.h indexing.h \
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)
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‎src/backend/catalog/dependency.c‎

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -66,6 +66,7 @@
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#include "commands/proclang.h"
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#include "commands/schemacmds.h"
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#include "commands/seclabel.h"
69+
#include "commands/sequence.h"
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#include "commands/trigger.h"
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#include "commands/typecmds.h"
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#include "nodes/nodeFuncs.h"
@@ -1114,6 +1115,11 @@ doDeletion(const ObjectAddress *object, int flags)
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else
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heap_drop_with_catalog(object->objectId);
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}
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/* for a sequence, in addition to dropping the heap, also
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* delete pg_sequence tuple */
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if (relKind == RELKIND_SEQUENCE)
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DeleteSequenceTuple(object->objectId);
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break;
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}
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‎src/backend/catalog/information_schema.sql‎

Lines changed: 7 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1535,15 +1535,16 @@ CREATE VIEW sequences AS
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CAST(64 AS cardinal_number) AS numeric_precision,
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CAST(2 AS cardinal_number) AS numeric_precision_radix,
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CAST(0 AS cardinal_number) AS numeric_scale,
1538-
CAST(p.start_value AS character_data) AS start_value,
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CAST(p.minimum_value AS character_data) AS minimum_value,
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CAST(p.maximum_value AS character_data) AS maximum_value,
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CAST(p.increment AS character_data) AS increment,
1542-
CAST(CASE WHEN p.cycle_option THEN 'YES' ELSE 'NO' END AS yes_or_no) AS cycle_option
1543-
FROM pg_namespace nc, pg_class c, LATERAL pg_sequence_parameters(c.oid) p
1538+
CAST(s.seqstart AS character_data) AS start_value,
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CAST(s.seqmin AS character_data) AS minimum_value,
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CAST(s.seqmax AS character_data) AS maximum_value,
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CAST(s.seqincrement AS character_data) AS increment,
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CAST(CASE WHEN s.seqcycle THEN 'YES' ELSE 'NO' END AS yes_or_no) AS cycle_option
1543+
FROM pg_namespace nc, pg_class c, pg_sequence s
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WHERE c.relnamespace = nc.oid
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AND c.relkind = 'S'
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AND (NOT pg_is_other_temp_schema(nc.oid))
1547+
AND c.oid = s.seqrelid
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AND (pg_has_role(c.relowner, 'USAGE')
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OR has_sequence_privilege(c.oid, 'SELECT, UPDATE, USAGE') );
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‎src/backend/catalog/system_views.sql‎

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -169,15 +169,15 @@ CREATE OR REPLACE VIEW pg_sequences AS
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N.nspname AS schemaname,
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C.relname AS sequencename,
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pg_get_userbyid(C.relowner) AS sequenceowner,
172-
p.start_value AS start_value,
173-
p.minimum_value AS min_value,
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p.maximum_value AS max_value,
175-
p.increment AS increment_by,
176-
p.cycle_option AS cycle,
177-
p.cache_size AS cache_size,
172+
S.seqstart AS start_value,
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S.seqmin AS min_value,
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S.seqmax AS max_value,
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S.seqincrement AS increment_by,
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S.seqcycle AS cycle,
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S.seqcache AS cache_size,
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pg_sequence_last_value(C.oid) AS last_value
179-
FROM pg_class C LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace),
180-
LATERAL pg_sequence_parameters(C.oid) p
179+
FROM pg_sequence S JOIN pg_class C ON (C.oid = S.seqrelid)
180+
LEFT JOIN pg_namespace N ON (N.oid = C.relnamespace)
181181
WHERE NOT pg_is_other_temp_schema(N.oid)
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AND relkind = 'S';
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