The SQL standard has been ambiguous about whether null values in
unique constraints should be considered equal or not. Different
implementations have different behaviors. In the SQL:202x draft, this
has been formalized by making this implementation-defined and adding
an option on unique constraint definitions UNIQUE [ NULLS [NOT]
DISTINCT ] to choose a behavior explicitly.
This patch adds this option to PostgreSQL. The default behavior
remains UNIQUE NULLS DISTINCT. Making this happen in the btree code
is apparently pretty easy; most of the patch is just to carry the flag
around to all the places that need it.
The CREATE UNIQUE INDEX syntax extension is not from the standard,
it's my own invention.
(I named all the internal flags, catalog columns, etc. in the
negative ("nulls not distinct") so that the default PostgreSQL
behavior is the default if the flag is false. But perhaps the double
negatives make some code harder to read.)
From 14bd23b4f164c4298262e7fbfec1a49292d16e27 Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <pe...@eisentraut.org>
Date: Fri, 27 Aug 2021 14:31:46 +0200
Subject: [PATCH] Add UNIQUE null treatment option
The SQL standard has been ambiguous about whether null values in
unique constraints should be considered equal or not. Different
implementations have different behaviors. In the SQL:202x draft, this
has been formalized by making this implementation-defined and adding
an option on unique constraint definitions UNIQUE [ NULLS [NOT]
DISTINCT ] to choose a behavior explicitly.
This patch adds this option to PostgreSQL. The default behavior
remains UNIQUE NULLS DISTINCT. Making this happen in the btree code
is pretty easy; most of the patch is just to carry the flag around to
all the places that need it.
The CREATE UNIQUE INDEX syntax extension is not from the standard,
it's my own invention.
XXX I named all the internal flags, catalog columns, etc. in the
negative ("nulls not distinct") so that the default PostgreSQL
behavior is the default if the flag is false. But perhaps the double
negatives make some code harder to read.
---
doc/src/sgml/catalogs.sgml | 13 ++++++
doc/src/sgml/ddl.sgml | 29 +++++++++---
doc/src/sgml/information_schema.sgml | 12 +++++
doc/src/sgml/ref/alter_table.sgml | 4 +-
doc/src/sgml/ref/create_index.sgml | 13 ++++++
doc/src/sgml/ref/create_table.sgml | 11 ++---
src/backend/access/nbtree/nbtinsert.c | 10 ++---
src/backend/access/nbtree/nbtsort.c | 15 ++++++-
src/backend/catalog/index.c | 7 +++
src/backend/catalog/information_schema.sql | 9 +++-
src/backend/catalog/sql_features.txt | 1 +
src/backend/catalog/toasting.c | 1 +
src/backend/commands/indexcmds.c | 3 +-
src/backend/nodes/copyfuncs.c | 2 +
src/backend/nodes/equalfuncs.c | 2 +
src/backend/nodes/makefuncs.c | 3 +-
src/backend/nodes/outfuncs.c | 2 +
src/backend/parser/gram.y | 47 ++++++++++++--------
src/backend/parser/parse_utilcmd.c | 3 ++
src/backend/utils/adt/ruleutils.c | 23 +++++++---
src/backend/utils/cache/relcache.c | 1 +
src/backend/utils/sort/tuplesort.c | 8 +++-
src/bin/pg_dump/pg_dump.c | 9 +++-
src/bin/pg_dump/pg_dump.h | 1 +
src/bin/psql/describe.c | 30 ++++++++++---
src/include/catalog/pg_index.h | 1 +
src/include/nodes/execnodes.h | 1 +
src/include/nodes/makefuncs.h | 2 +-
src/include/nodes/parsenodes.h | 2 +
src/include/utils/tuplesort.h | 1 +
src/test/regress/expected/create_index.out | 51 ++++++++++++++++++++++
src/test/regress/input/constraints.source | 14 ++++++
src/test/regress/output/constraints.source | 23 ++++++++++
src/test/regress/sql/create_index.sql | 36 +++++++++++++++
34 files changed, 332 insertions(+), 58 deletions(-)
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index 2b2c70a26e..fd49738d4f 100644
--- a/doc/src/sgml/catalogs.sgml
+++ b/doc/src/sgml/catalogs.sgml
@@ -4256,6 +4256,19 @@ <title><structname>pg_index</structname> Columns</title>
</para></entry>
</row>
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>indnullsnotdistinct</structfield> <type>bool</type>
+ </para>
+ <para>
+ This value is only used for unique indexes. If false, this unique
+ index will consider null values distinct (so the index can contain
+ multiple null values in a column, the default PostgreSQL behavior). If
+ it is true, it will consider null values to be equal (so the index can
+ only contain one null value in a column).
+ </para></entry>
+ </row>
+
<row>
<entry role="catalog_table_entry"><para role="column_definition">
<structfield>indisprimary</structfield> <type>bool</type>
diff --git a/doc/src/sgml/ddl.sgml b/doc/src/sgml/ddl.sgml
index e0ffb020bf..815a2e23f9 100644
--- a/doc/src/sgml/ddl.sgml
+++ b/doc/src/sgml/ddl.sgml
@@ -759,14 +759,33 @@ <title>Unique Constraints</title>
In general, a unique constraint is violated if there is more than
one row in the table where the values of all of the
columns included in the constraint are equal.
- However, two null values are never considered equal in this
+ By default, two null values are not considered equal in this
comparison. That means even in the presence of a
unique constraint it is possible to store duplicate
rows that contain a null value in at least one of the constrained
- columns. This behavior conforms to the SQL standard, but we have
- heard that other SQL databases might not follow this rule. So be
- careful when developing applications that are intended to be
- portable.
+ columns. This behavior can be changed by adding the clause <literal>NULLS
+ NOT DISTINCT</literal>, like
+<programlisting>
+CREATE TABLE products (
+ product_no integer UNIQUE <emphasis>NULLS NOT DISTINCT</emphasis>,
+ name text,
+ price numeric
+);
+</programlisting>
+ or
+<programlisting>
+CREATE TABLE products (
+ product_no integer,
+ name text,
+ price numeric,
+ UNIQUE <emphasis>NULLS NOT DISTINCT</emphasis> (product_no)
+);
+</programlisting>
+ The default behavior can be specified explicitly using <literal>NULLS
+ DISTINCT</literal>. The default null treatment in unique constraints is
+ implementation-defined according to the SQL standard, and other
+ implementations have a different behavior. So be careful when developing
+ applications that are intended to be portable.
</para>
</sect2>
diff --git a/doc/src/sgml/information_schema.sgml
b/doc/src/sgml/information_schema.sgml
index c5e68c175f..350c75bc31 100644
--- a/doc/src/sgml/information_schema.sgml
+++ b/doc/src/sgml/information_schema.sgml
@@ -6899,6 +6899,18 @@ <title><structname>table_constraints</structname>
Columns</title>
<literal>YES</literal>)
</para></entry>
</row>
+
+ <row>
+ <entry role="catalog_table_entry"><para role="column_definition">
+ <structfield>nulls_distinct</structfield> <type>yes_or_no</type>
+ </para>
+ <para>
+ If the constraint is a unique constraint, then <literal>YES</literal>
+ if the constraint treats nulls as distinct or <literal>NO</literal> if
+ it treats nulls as not distinct, otherwise null for other types of
+ constraints.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
diff --git a/doc/src/sgml/ref/alter_table.sgml
b/doc/src/sgml/ref/alter_table.sgml
index 81291577f8..0edf3563d3 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -103,7 +103,7 @@
DEFAULT <replaceable>default_expr</replaceable> |
GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ (
<replaceable>sequence_options</replaceable> ) ] |
- UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
+ UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable
class="parameter">index_parameters</replaceable> |
PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
REFERENCES <replaceable class="parameter">reftable</replaceable> [ (
<replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH
PARTIAL | MATCH SIMPLE ]
[ ON DELETE <replaceable
class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable
class="parameter">referential_action</replaceable> ] }
@@ -113,7 +113,7 @@
[ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
{ CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO
INHERIT ] |
- UNIQUE ( <replaceable class="parameter">column_name</replaceable> [, ... ] )
<replaceable class="parameter">index_parameters</replaceable> |
+ UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable
class="parameter">column_name</replaceable> [, ... ] ) <replaceable
class="parameter">index_parameters</replaceable> |
PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [,
... ] ) <replaceable class="parameter">index_parameters</replaceable> |
EXCLUDE [ USING <replaceable class="parameter">index_method</replaceable> ]
( <replaceable class="parameter">exclude_element</replaceable> WITH
<replaceable class="parameter">operator</replaceable> [, ... ] ) <replaceable
class="parameter">index_parameters</replaceable> [ WHERE ( <replaceable
class="parameter">predicate</replaceable> ) ] |
FOREIGN KEY ( <replaceable class="parameter">column_name</replaceable> [,
... ] ) REFERENCES <replaceable class="parameter">reftable</replaceable> [ (
<replaceable class="parameter">refcolumn</replaceable> [, ... ] ) ]
diff --git a/doc/src/sgml/ref/create_index.sgml
b/doc/src/sgml/ref/create_index.sgml
index cc484d5b39..453794b5d2 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -24,6 +24,7 @@
CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ [ IF NOT EXISTS ] <replaceable
class="parameter">name</replaceable> ] ON [ ONLY ] <replaceable
class="parameter">table_name</replaceable> [ USING <replaceable
class="parameter">method</replaceable> ]
( { <replaceable class="parameter">column_name</replaceable> | (
<replaceable class="parameter">expression</replaceable> ) } [ COLLATE
<replaceable class="parameter">collation</replaceable> ] [ <replaceable
class="parameter">opclass</replaceable> [ ( <replaceable
class="parameter">opclass_parameter</replaceable> = <replaceable
class="parameter">value</replaceable> [, ... ] ) ] ] [ ASC | DESC ] [ NULLS {
FIRST | LAST } ] [, ...] )
[ INCLUDE ( <replaceable class="parameter">column_name</replaceable> [,
...] ) ]
+ [ NULLS [ NOT ] DISTINCT ]
[ WITH ( <replaceable class="parameter">storage_parameter</replaceable> [=
<replaceable class="parameter">value</replaceable>] [, ... ] ) ]
[ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
[ WHERE <replaceable class="parameter">predicate</replaceable> ]
@@ -331,6 +332,18 @@ <title>Parameters</title>
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><literal>NULLS DISTINCT</literal></term>
+ <term><literal>NULLS NOT DISTINCT</literal></term>
+ <listitem>
+ <para>
+ Specifies whether for a unique index, null values should be considered
+ distinct (not equal). The default is that they are distinct, so that
+ a unique index could contain multiple null values in a column.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><replaceable
class="parameter">storage_parameter</replaceable></term>
<listitem>
diff --git a/doc/src/sgml/ref/create_table.sgml
b/doc/src/sgml/ref/create_table.sgml
index 473a0a4aeb..35fc6324a5 100644
--- a/doc/src/sgml/ref/create_table.sgml
+++ b/doc/src/sgml/ref/create_table.sgml
@@ -67,7 +67,7 @@
DEFAULT <replaceable>default_expr</replaceable> |
GENERATED ALWAYS AS ( <replaceable>generation_expr</replaceable> ) STORED |
GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ (
<replaceable>sequence_options</replaceable> ) ] |
- UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
+ UNIQUE [ NULLS [ NOT ] DISTINCT ] <replaceable
class="parameter">index_parameters</replaceable> |
PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
REFERENCES <replaceable class="parameter">reftable</replaceable> [ (
<replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH
PARTIAL | MATCH SIMPLE ]
[ ON DELETE <replaceable
class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable
class="parameter">referential_action</replaceable> ] }
@@ -77,7 +77,7 @@
[ CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> ]
{ CHECK ( <replaceable class="parameter">expression</replaceable> ) [ NO
INHERIT ] |
- UNIQUE ( <replaceable class="parameter">column_name</replaceable> [, ... ] )
<replaceable class="parameter">index_parameters</replaceable> |
+ UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable
class="parameter">column_name</replaceable> [, ... ] ) <replaceable
class="parameter">index_parameters</replaceable> |
PRIMARY KEY ( <replaceable class="parameter">column_name</replaceable> [,
... ] ) <replaceable class="parameter">index_parameters</replaceable> |
EXCLUDE [ USING <replaceable class="parameter">index_method</replaceable> ]
( <replaceable class="parameter">exclude_element</replaceable> WITH
<replaceable class="parameter">operator</replaceable> [, ... ] ) <replaceable
class="parameter">index_parameters</replaceable> [ WHERE ( <replaceable
class="parameter">predicate</replaceable> ) ] |
FOREIGN KEY ( <replaceable class="parameter">column_name</replaceable> [,
... ] ) REFERENCES <replaceable class="parameter">reftable</replaceable> [ (
<replaceable class="parameter">refcolumn</replaceable> [, ... ] ) ]
@@ -913,8 +913,8 @@ <title>Parameters</title>
</varlistentry>
<varlistentry>
- <term><literal>UNIQUE</literal> (column constraint)</term>
- <term><literal>UNIQUE ( <replaceable
class="parameter">column_name</replaceable> [, ... ] )</literal>
+ <term><literal>UNIQUE [ NULLS [ NOT ] DISTINCT ]</literal> (column
constraint)</term>
+ <term><literal>UNIQUE [ NULLS [ NOT ] DISTINCT ] ( <replaceable
class="parameter">column_name</replaceable> [, ... ] )</literal>
<optional> <literal>INCLUDE ( <replaceable
class="parameter">column_name</replaceable> [, ...])</literal> </optional>
(table constraint)</term>
<listitem>
@@ -930,7 +930,8 @@ <title>Parameters</title>
<para>
For the purpose of a unique constraint, null values are not
- considered equal.
+ considered equal, unless <literal>NULLS NOT DISTINCT</literal> is
+ specified.
</para>
<para>
diff --git a/src/backend/access/nbtree/nbtinsert.c
b/src/backend/access/nbtree/nbtinsert.c
index 6ac205c98e..f7fc015ae3 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -111,7 +111,7 @@ _bt_doinsert(Relation rel, IndexTuple itup,
if (checkingunique)
{
- if (!itup_key->anynullkeys)
+ if (!itup_key->anynullkeys ||
rel->rd_index->indnullsnotdistinct)
{
/* No (heapkeyspace) scantid until uniqueness
established */
itup_key->scantid = NULL;
@@ -397,9 +397,9 @@ _bt_search_insert(Relation rel, BTInsertState insertstate)
* _bt_findinsertloc() to reuse most of the binary search work we do
* here.
*
- * Do not call here when there are NULL values in scan key. NULL should be
- * considered unequal to NULL when checking for duplicates, but we are not
- * prepared to handle that correctly.
+ * This code treats NULLs as equal, unlike the default semantics for unique
+ * indexes. So do not call here when there are NULL values in scan key and
+ * the index uses the default NULLS DISTINCT mode.
*/
static TransactionId
_bt_check_unique(Relation rel, BTInsertState insertstate, Relation heapRel,
@@ -443,7 +443,7 @@ _bt_check_unique(Relation rel, BTInsertState insertstate,
Relation heapRel,
* Scan over all equal tuples, looking for live conflicts.
*/
Assert(!insertstate->bounds_valid || insertstate->low == offset);
- Assert(!itup_key->anynullkeys);
+ Assert(!itup_key->anynullkeys || rel->rd_index->indnullsnotdistinct);
Assert(itup_key->scantid == NULL);
for (;;)
{
diff --git a/src/backend/access/nbtree/nbtsort.c
b/src/backend/access/nbtree/nbtsort.c
index 54c8eb1289..0c012da24d 100644
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -89,6 +89,7 @@ typedef struct BTSpool
Relation heap;
Relation index;
bool isunique;
+ bool nulls_not_distinct;
} BTSpool;
/*
@@ -106,6 +107,7 @@ typedef struct BTShared
Oid heaprelid;
Oid indexrelid;
bool isunique;
+ bool nulls_not_distinct;
bool isconcurrent;
int scantuplesortstates;
@@ -206,6 +208,7 @@ typedef struct BTLeader
typedef struct BTBuildState
{
bool isunique;
+ bool nulls_not_distinct;
bool havedead;
Relation heap;
BTSpool *spool;
@@ -307,6 +310,7 @@ btbuild(Relation heap, Relation index, IndexInfo *indexInfo)
#endif /* BTREE_BUILD_STATS */
buildstate.isunique = indexInfo->ii_Unique;
+ buildstate.nulls_not_distinct = indexInfo->ii_NullsNotDistinct;
buildstate.havedead = false;
buildstate.heap = heap;
buildstate.spool = NULL;
@@ -380,6 +384,7 @@ _bt_spools_heapscan(Relation heap, Relation index,
BTBuildState *buildstate,
btspool->heap = heap;
btspool->index = index;
btspool->isunique = indexInfo->ii_Unique;
+ btspool->nulls_not_distinct = indexInfo->ii_NullsNotDistinct;
/* Save as primary spool */
buildstate->spool = btspool;
@@ -429,6 +434,7 @@ _bt_spools_heapscan(Relation heap, Relation index,
BTBuildState *buildstate,
*/
buildstate->spool->sortstate =
tuplesort_begin_index_btree(heap, index, buildstate->isunique,
+
buildstate->nulls_not_distinct,
maintenance_work_mem, coordinate,
false);
@@ -468,7 +474,7 @@ _bt_spools_heapscan(Relation heap, Relation index,
BTBuildState *buildstate,
* full, so we give it only work_mem
*/
buildstate->spool2->sortstate =
- tuplesort_begin_index_btree(heap, index, false,
work_mem,
+ tuplesort_begin_index_btree(heap, index, false, false,
work_mem,
coordinate2, false);
}
@@ -1554,6 +1560,7 @@ _bt_begin_parallel(BTBuildState *buildstate, bool
isconcurrent, int request)
btshared->heaprelid = RelationGetRelid(btspool->heap);
btshared->indexrelid = RelationGetRelid(btspool->index);
btshared->isunique = btspool->isunique;
+ btshared->nulls_not_distinct = btspool->nulls_not_distinct;
btshared->isconcurrent = isconcurrent;
btshared->scantuplesortstates = scantuplesortstates;
ConditionVariableInit(&btshared->workersdonecv);
@@ -1747,6 +1754,7 @@ _bt_leader_participate_as_worker(BTBuildState *buildstate)
leaderworker->heap = buildstate->spool->heap;
leaderworker->index = buildstate->spool->index;
leaderworker->isunique = buildstate->spool->isunique;
+ leaderworker->nulls_not_distinct =
buildstate->spool->nulls_not_distinct;
/* Initialize second spool, if required */
if (!btleader->btshared->isunique)
@@ -1839,6 +1847,7 @@ _bt_parallel_build_main(dsm_segment *seg, shm_toc *toc)
btspool->heap = heapRel;
btspool->index = indexRel;
btspool->isunique = btshared->isunique;
+ btspool->nulls_not_distinct = btshared->nulls_not_distinct;
/* Look up shared state private to tuplesort.c */
sharedsort = shm_toc_lookup(toc, PARALLEL_KEY_TUPLESORT, false);
@@ -1921,6 +1930,7 @@ _bt_parallel_scan_and_sort(BTSpool *btspool, BTSpool
*btspool2,
btspool->sortstate = tuplesort_begin_index_btree(btspool->heap,
btspool->index,
btspool->isunique,
+
btspool->nulls_not_distinct,
sortmem, coordinate,
false);
@@ -1943,13 +1953,14 @@ _bt_parallel_scan_and_sort(BTSpool *btspool, BTSpool
*btspool2,
coordinate2->nParticipants = -1;
coordinate2->sharedsort = sharedsort2;
btspool2->sortstate =
- tuplesort_begin_index_btree(btspool->heap,
btspool->index, false,
+ tuplesort_begin_index_btree(btspool->heap,
btspool->index, false, false,
Min(sortmem, work_mem), coordinate2,
false);
}
/* Fill in buildstate for _bt_build_callback() */
buildstate.isunique = btshared->isunique;
+ buildstate.nulls_not_distinct = btshared->nulls_not_distinct;
buildstate.havedead = false;
buildstate.heap = btspool->heap;
buildstate.spool = btspool;
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 26bfa74ce7..c73d3d33a7 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -612,6 +612,7 @@ UpdateIndexRelation(Oid indexoid,
values[Anum_pg_index_indnatts - 1] =
Int16GetDatum(indexInfo->ii_NumIndexAttrs);
values[Anum_pg_index_indnkeyatts - 1] =
Int16GetDatum(indexInfo->ii_NumIndexKeyAttrs);
values[Anum_pg_index_indisunique - 1] =
BoolGetDatum(indexInfo->ii_Unique);
+ values[Anum_pg_index_indnullsnotdistinct - 1] =
BoolGetDatum(indexInfo->ii_NullsNotDistinct);
values[Anum_pg_index_indisprimary - 1] = BoolGetDatum(primary);
values[Anum_pg_index_indisexclusion - 1] = BoolGetDatum(isexclusion);
values[Anum_pg_index_indimmediate - 1] = BoolGetDatum(immediate);
@@ -1348,6 +1349,7 @@ index_concurrently_create_copy(Relation heapRelation, Oid
oldIndexId,
indexExprs,
indexPreds,
oldInfo->ii_Unique,
+
oldInfo->ii_NullsNotDistinct,
false, /* not ready
for inserts */
true);
@@ -2398,6 +2400,7 @@ BuildIndexInfo(Relation index)
RelationGetIndexExpressions(index),
RelationGetIndexPredicate(index),
indexStruct->indisunique,
+ indexStruct->indnullsnotdistinct,
indexStruct->indisready,
false);
@@ -2457,6 +2460,7 @@ BuildDummyIndexInfo(Relation index)
RelationGetDummyIndexExpressions(index),
NIL,
indexStruct->indisunique,
+ indexStruct->indnullsnotdistinct,
indexStruct->indisready,
false);
@@ -2490,6 +2494,9 @@ CompareIndexInfo(IndexInfo *info1, IndexInfo *info2,
if (info1->ii_Unique != info2->ii_Unique)
return false;
+ if (info1->ii_NullsNotDistinct != info2->ii_NullsNotDistinct)
+ return false;
+
/* indexes are only equivalent if they have the same access method */
if (info1->ii_Am != info2->ii_Am)
return false;
diff --git a/src/backend/catalog/information_schema.sql
b/src/backend/catalog/information_schema.sql
index 11d9dd60c2..caafb00c44 100644
--- a/src/backend/catalog/information_schema.sql
+++ b/src/backend/catalog/information_schema.sql
@@ -1838,7 +1838,11 @@ CREATE VIEW table_constraints AS
AS is_deferrable,
CAST(CASE WHEN c.condeferred THEN 'YES' ELSE 'NO' END AS yes_or_no)
AS initially_deferred,
- CAST('YES' AS yes_or_no) AS enforced
+ CAST('YES' AS yes_or_no) AS enforced,
+ CAST(CASE WHEN c.contype = 'u'
+ THEN CASE WHEN (SELECT NOT indnullsnotdistinct FROM
pg_index WHERE indexrelid = conindid) THEN 'YES' ELSE 'NO' END
+ END
+ AS yes_or_no) AS nulls_distinct
FROM pg_namespace nc,
pg_namespace nr,
@@ -1868,7 +1872,8 @@ CREATE VIEW table_constraints AS
CAST('CHECK' AS character_data) AS constraint_type,
CAST('NO' AS yes_or_no) AS is_deferrable,
CAST('NO' AS yes_or_no) AS initially_deferred,
- CAST('YES' AS yes_or_no) AS enforced
+ CAST('YES' AS yes_or_no) AS enforced,
+ CAST(NULL AS yes_or_no) AS nulls_distinct
FROM pg_namespace nr,
pg_class r,
diff --git a/src/backend/catalog/sql_features.txt
b/src/backend/catalog/sql_features.txt
index 9f424216e2..accac5315f 100644
--- a/src/backend/catalog/sql_features.txt
+++ b/src/backend/catalog/sql_features.txt
@@ -228,6 +228,7 @@ F263 Comma-separated predicates in simple CASE
expression NO
F271 Compound character literals YES
F281 LIKE enhancements YES
F291 UNIQUE predicate NO
+F292 UNIQUE null treatment YES SQL:202x draft
F301 CORRESPONDING in query expressions NO
F302 INTERSECT table operator YES
F302 INTERSECT table operator 01 INTERSECT DISTINCT table
operator YES
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 0db90c2011..9614f64b92 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -301,6 +301,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid
toastIndexOid,
indexInfo->ii_ExclusionStrats = NULL;
indexInfo->ii_OpclassOptions = NULL;
indexInfo->ii_Unique = true;
+ indexInfo->ii_NullsNotDistinct = false;
indexInfo->ii_ReadyForInserts = true;
indexInfo->ii_Concurrent = false;
indexInfo->ii_BrokenHotChain = false;
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index c14ca27c5e..ab48a40a20 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -226,7 +226,7 @@ CheckIndexCompatible(Oid oldId,
* ii_NumIndexKeyAttrs with same value.
*/
indexInfo = makeIndexInfo(numberOfAttributes, numberOfAttributes,
- accessMethodId, NIL,
NIL, false, false, false);
+ accessMethodId, NIL,
NIL, false, false, false, false);
typeObjectId = (Oid *) palloc(numberOfAttributes * sizeof(Oid));
collationObjectId = (Oid *) palloc(numberOfAttributes * sizeof(Oid));
classObjectId = (Oid *) palloc(numberOfAttributes * sizeof(Oid));
@@ -867,6 +867,7 @@ DefineIndex(Oid relationId,
NIL, /* expressions,
NIL for now */
make_ands_implicit((Expr *) stmt->whereClause),
stmt->unique,
+
stmt->nulls_not_distinct,
!concurrent,
concurrent);
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 38251c2b8e..361b60b02f 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -3056,6 +3056,7 @@ _copyConstraint(const Constraint *from)
COPY_NODE_FIELD(raw_expr);
COPY_STRING_FIELD(cooked_expr);
COPY_SCALAR_FIELD(generated_when);
+ COPY_SCALAR_FIELD(nulls_not_distinct);
COPY_NODE_FIELD(keys);
COPY_NODE_FIELD(including);
COPY_NODE_FIELD(exclusions);
@@ -3647,6 +3648,7 @@ _copyIndexStmt(const IndexStmt *from)
COPY_SCALAR_FIELD(oldCreateSubid);
COPY_SCALAR_FIELD(oldFirstRelfilenodeSubid);
COPY_SCALAR_FIELD(unique);
+ COPY_SCALAR_FIELD(nulls_not_distinct);
COPY_SCALAR_FIELD(primary);
COPY_SCALAR_FIELD(isconstraint);
COPY_SCALAR_FIELD(deferrable);
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 8a1762000c..88268aec0e 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1393,6 +1393,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
COMPARE_SCALAR_FIELD(oldCreateSubid);
COMPARE_SCALAR_FIELD(oldFirstRelfilenodeSubid);
COMPARE_SCALAR_FIELD(unique);
+ COMPARE_SCALAR_FIELD(nulls_not_distinct);
COMPARE_SCALAR_FIELD(primary);
COMPARE_SCALAR_FIELD(isconstraint);
COMPARE_SCALAR_FIELD(deferrable);
@@ -2677,6 +2678,7 @@ _equalConstraint(const Constraint *a, const Constraint *b)
COMPARE_NODE_FIELD(raw_expr);
COMPARE_STRING_FIELD(cooked_expr);
COMPARE_SCALAR_FIELD(generated_when);
+ COMPARE_SCALAR_FIELD(nulls_not_distinct);
COMPARE_NODE_FIELD(keys);
COMPARE_NODE_FIELD(including);
COMPARE_NODE_FIELD(exclusions);
diff --git a/src/backend/nodes/makefuncs.c b/src/backend/nodes/makefuncs.c
index 01c110cd2f..52aaf0b7a5 100644
--- a/src/backend/nodes/makefuncs.c
+++ b/src/backend/nodes/makefuncs.c
@@ -741,7 +741,7 @@ make_ands_implicit(Expr *clause)
*/
IndexInfo *
makeIndexInfo(int numattrs, int numkeyattrs, Oid amoid, List *expressions,
- List *predicates, bool unique, bool isready, bool
concurrent)
+ List *predicates, bool unique, bool
nulls_not_distinct, bool isready, bool concurrent)
{
IndexInfo *n = makeNode(IndexInfo);
@@ -750,6 +750,7 @@ makeIndexInfo(int numattrs, int numkeyattrs, Oid amoid,
List *expressions,
Assert(n->ii_NumIndexKeyAttrs != 0);
Assert(n->ii_NumIndexKeyAttrs <= n->ii_NumIndexAttrs);
n->ii_Unique = unique;
+ n->ii_NullsNotDistinct = nulls_not_distinct;
n->ii_ReadyForInserts = isready;
n->ii_Concurrent = concurrent;
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 87561cbb6f..cd1feb7b57 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -2770,6 +2770,7 @@ _outIndexStmt(StringInfo str, const IndexStmt *node)
WRITE_UINT_FIELD(oldCreateSubid);
WRITE_UINT_FIELD(oldFirstRelfilenodeSubid);
WRITE_BOOL_FIELD(unique);
+ WRITE_BOOL_FIELD(nulls_not_distinct);
WRITE_BOOL_FIELD(primary);
WRITE_BOOL_FIELD(isconstraint);
WRITE_BOOL_FIELD(deferrable);
@@ -3702,6 +3703,7 @@ _outConstraint(StringInfo str, const Constraint *node)
case CONSTR_UNIQUE:
appendStringInfoString(str, "UNIQUE");
+ WRITE_BOOL_FIELD(nulls_not_distinct);
WRITE_NODE_FIELD(keys);
WRITE_NODE_FIELD(including);
WRITE_NODE_FIELD(options);
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 39a2849eba..ea7cd03cd2 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -602,6 +602,7 @@ static Node *makeRecursiveViewSelect(char *relname, List
*aliases, Node *query);
%type <ival> opt_window_exclusion_clause
%type <str> opt_existing_window_name
%type <boolean> opt_if_not_exists
+%type <boolean> opt_unique_null_treatment
%type <ival> generated_when override_kind
%type <partspec> PartitionSpec OptPartitionSpec
%type <partelem> part_elem
@@ -3600,15 +3601,16 @@ ColConstraintElem:
n->location = @1;
$$ = (Node *)n;
}
- | UNIQUE opt_definition OptConsTableSpace
+ | UNIQUE opt_unique_null_treatment opt_definition
OptConsTableSpace
{
Constraint *n = makeNode(Constraint);
n->contype = CONSTR_UNIQUE;
n->location = @1;
+ n->nulls_not_distinct = !$2;
n->keys = NULL;
- n->options = $2;
+ n->options = $3;
n->indexname = NULL;
- n->indexspace = $3;
+ n->indexspace = $4;
$$ = (Node *)n;
}
| PRIMARY KEY opt_definition OptConsTableSpace
@@ -3692,6 +3694,12 @@ ColConstraintElem:
}
;
+opt_unique_null_treatment:
+ NULLS_P DISTINCT { $$ = true; }
+ | NULLS_P NOT DISTINCT { $$ = false; }
+ | /*EMPTY*/ { $$ = true; }
+ ;
+
generated_when:
ALWAYS { $$ =
ATTRIBUTE_IDENTITY_ALWAYS; }
| BY DEFAULT { $$ = ATTRIBUTE_IDENTITY_BY_DEFAULT; }
@@ -3804,18 +3812,19 @@ ConstraintElem:
n->initially_valid =
!n->skip_validation;
$$ = (Node *)n;
}
- | UNIQUE '(' columnList ')' opt_c_include
opt_definition OptConsTableSpace
+ | UNIQUE opt_unique_null_treatment '(' columnList ')'
opt_c_include opt_definition OptConsTableSpace
ConstraintAttributeSpec
{
Constraint *n = makeNode(Constraint);
n->contype = CONSTR_UNIQUE;
n->location = @1;
- n->keys = $3;
- n->including = $5;
- n->options = $6;
+ n->nulls_not_distinct = !$2;
+ n->keys = $4;
+ n->including = $6;
+ n->options = $7;
n->indexname = NULL;
- n->indexspace = $7;
- processCASbits($8, @8, "UNIQUE",
+ n->indexspace = $8;
+ processCASbits($9, @9, "UNIQUE",
&n->deferrable, &n->initdeferred, NULL,
NULL,
yyscanner);
$$ = (Node *)n;
@@ -7316,7 +7325,7 @@ defacl_privilege_target:
IndexStmt: CREATE opt_unique INDEX opt_concurrently opt_index_name
ON relation_expr access_method_clause '(' index_params
')'
- opt_include opt_reloptions OptTableSpace where_clause
+ opt_include opt_unique_null_treatment opt_reloptions
OptTableSpace where_clause
{
IndexStmt *n = makeNode(IndexStmt);
n->unique = $2;
@@ -7326,9 +7335,10 @@ IndexStmt: CREATE opt_unique INDEX
opt_concurrently opt_index_name
n->accessMethod = $8;
n->indexParams = $10;
n->indexIncludingParams = $12;
- n->options = $13;
- n->tableSpace = $14;
- n->whereClause = $15;
+ n->nulls_not_distinct = !$13;
+ n->options = $14;
+ n->tableSpace = $15;
+ n->whereClause = $16;
n->excludeOpNames = NIL;
n->idxcomment = NULL;
n->indexOid = InvalidOid;
@@ -7346,7 +7356,7 @@ IndexStmt: CREATE opt_unique INDEX
opt_concurrently opt_index_name
}
| CREATE opt_unique INDEX opt_concurrently IF_P NOT
EXISTS name
ON relation_expr access_method_clause '(' index_params
')'
- opt_include opt_reloptions OptTableSpace where_clause
+ opt_include opt_unique_null_treatment opt_reloptions
OptTableSpace where_clause
{
IndexStmt *n = makeNode(IndexStmt);
n->unique = $2;
@@ -7356,9 +7366,10 @@ IndexStmt: CREATE opt_unique INDEX
opt_concurrently opt_index_name
n->accessMethod = $11;
n->indexParams = $13;
n->indexIncludingParams = $15;
- n->options = $16;
- n->tableSpace = $17;
- n->whereClause = $18;
+ n->nulls_not_distinct = !$16;
+ n->options = $17;
+ n->tableSpace = $18;
+ n->whereClause = $19;
n->excludeOpNames = NIL;
n->idxcomment = NULL;
n->indexOid = InvalidOid;
@@ -13621,7 +13632,7 @@ a_expr: c_expr
{ $$ = $1; }
else
$$ = (Node *)
makeA_Expr(AEXPR_OP_ALL, $2, $1, $5, @2);
}
- | UNIQUE select_with_parens
+ | UNIQUE opt_unique_null_treatment select_with_parens
{
/* Not sure how to get rid of the
parentheses
* but there are lots of shift/reduce
errors without them.
diff --git a/src/backend/parser/parse_utilcmd.c
b/src/backend/parser/parse_utilcmd.c
index e5eefdbd43..5c646fd621 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -1581,6 +1581,7 @@ generateClonedIndexStmt(RangeVar *heapRel, Relation
source_idx,
index->oldCreateSubid = InvalidSubTransactionId;
index->oldFirstRelfilenodeSubid = InvalidSubTransactionId;
index->unique = idxrec->indisunique;
+ index->nulls_not_distinct = idxrec->indnullsnotdistinct;
index->primary = idxrec->indisprimary;
index->transformed = true; /* don't need transformIndexStmt */
index->concurrent = false;
@@ -2112,6 +2113,7 @@ transformIndexConstraints(CreateStmtContext *cxt)
equal(index->whereClause,
priorindex->whereClause) &&
equal(index->excludeOpNames,
priorindex->excludeOpNames) &&
strcmp(index->accessMethod,
priorindex->accessMethod) == 0 &&
+ index->nulls_not_distinct ==
priorindex->nulls_not_distinct &&
index->deferrable == priorindex->deferrable &&
index->initdeferred == priorindex->initdeferred)
{
@@ -2178,6 +2180,7 @@ transformIndexConstraint(Constraint *constraint,
CreateStmtContext *cxt)
* DefineIndex will check for it.
*/
}
+ index->nulls_not_distinct = constraint->nulls_not_distinct;
index->isconstraint = true;
index->deferrable = constraint->deferrable;
index->initdeferred = constraint->initdeferred;
diff --git a/src/backend/utils/adt/ruleutils.c
b/src/backend/utils/adt/ruleutils.c
index 4df8cc5abf..c75e630fcc 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -1440,6 +1440,9 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
{
appendStringInfoChar(&buf, ')');
+ if (idxrec->indnullsnotdistinct)
+ appendStringInfo(&buf, " NULLS NOT DISTINCT");
+
/*
* If it has options, append "WITH (options)"
*/
@@ -2298,9 +2301,20 @@ pg_get_constraintdef_worker(Oid constraintId, bool
fullCommand,
/* Start off the constraint definition */
if (conForm->contype == CONSTRAINT_PRIMARY)
- appendStringInfoString(&buf, "PRIMARY
KEY (");
+ appendStringInfoString(&buf, "PRIMARY
KEY ");
else
- appendStringInfoString(&buf, "UNIQUE
(");
+ appendStringInfoString(&buf, "UNIQUE ");
+
+ indexId = conForm->conindid;
+
+ indtup = SearchSysCache1(INDEXRELID,
ObjectIdGetDatum(indexId));
+ if (!HeapTupleIsValid(indtup))
+ elog(ERROR, "cache lookup failed for
index %u", indexId);
+ if (conForm->contype == CONSTRAINT_UNIQUE &&
+ ((Form_pg_index)
GETSTRUCT(indtup))->indnullsnotdistinct)
+ appendStringInfoString(&buf, "NULLS NOT
DISTINCT ");
+
+ appendStringInfoString(&buf, "(");
/* Fetch and build target column list */
val = SysCacheGetAttr(CONSTROID, tup,
@@ -2313,12 +2327,7 @@ pg_get_constraintdef_worker(Oid constraintId, bool
fullCommand,
appendStringInfoChar(&buf, ')');
- indexId = conForm->conindid;
-
/* Build including column list (from
pg_index.indkeys) */
- indtup = SearchSysCache1(INDEXRELID,
ObjectIdGetDatum(indexId));
- if (!HeapTupleIsValid(indtup))
- elog(ERROR, "cache lookup failed for
index %u", indexId);
val = SysCacheGetAttr(INDEXRELID, indtup,
Anum_pg_index_indnatts, &isnull);
if (isnull)
diff --git a/src/backend/utils/cache/relcache.c
b/src/backend/utils/cache/relcache.c
index 13d9994af3..615478c31d 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -2237,6 +2237,7 @@ RelationReloadIndexInfo(Relation relation)
* the array fields are allowed to change, though.
*/
relation->rd_index->indisunique = index->indisunique;
+ relation->rd_index->indnullsnotdistinct =
index->indnullsnotdistinct;
relation->rd_index->indisprimary = index->indisprimary;
relation->rd_index->indisexclusion = index->indisexclusion;
relation->rd_index->indimmediate = index->indimmediate;
diff --git a/src/backend/utils/sort/tuplesort.c
b/src/backend/utils/sort/tuplesort.c
index b17347b214..d874f9b75d 100644
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -460,6 +460,7 @@ struct Tuplesortstate
/* These are specific to the index_btree subcase: */
bool enforceUnique; /* complain if we find duplicate tuples
*/
+ bool uniqueNullsNotDistinct; /* unique constraint null
treatment */
/* These are specific to the index_hash subcase: */
uint32 high_mask; /* masks for sortable part of
hash code */
@@ -1066,6 +1067,7 @@ Tuplesortstate *
tuplesort_begin_index_btree(Relation heapRel,
Relation indexRel,
bool enforceUnique,
+ bool
uniqueNullsNotDistinct,
int workMem,
SortCoordinate
coordinate,
bool randomAccess)
@@ -1104,6 +1106,7 @@ tuplesort_begin_index_btree(Relation heapRel,
state->heapRel = heapRel;
state->indexRel = indexRel;
state->enforceUnique = enforceUnique;
+ state->uniqueNullsNotDistinct = uniqueNullsNotDistinct;
indexScanKey = _bt_mkscankey(indexRel, NULL);
@@ -4267,14 +4270,15 @@ comparetup_index_btree(const SortTuple *a, const
SortTuple *b,
/*
* If btree has asked us to enforce uniqueness, complain if two equal
- * tuples are detected (unless there was at least one NULL field).
+ * tuples are detected (unless there was at least one NULL field and
NULLS
+ * NOT DISTINCT was not set).
*
* It is sufficient to make the test here, because if two tuples are
equal
* they *must* get compared at some stage of the sort --- otherwise the
* sort algorithm wouldn't have checked whether one must appear before
the
* other.
*/
- if (state->enforceUnique && !equal_hasnull)
+ if (state->enforceUnique && !(!state->uniqueNullsNotDistinct &&
equal_hasnull))
{
Datum values[INDEX_MAX_KEYS];
bool isnull[INDEX_MAX_KEYS];
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 90ac445bcd..cbed55bee8 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -7180,6 +7180,7 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int
numTables)
i_indkey,
i_indisclustered,
i_indisreplident,
+ i_indnullsnotdistinct,
i_contype,
i_conname,
i_condeferrable,
@@ -7237,6 +7238,7 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int
numTables)
"i.indnatts AS
indnatts, "
"i.indkey,
i.indisclustered, "
"i.indisreplident, "
+
"i.indnullsnotdistinct, " // TODO: make version-specific
"c.contype,
c.conname, "
"c.condeferrable,
c.condeferred, "
"c.tableoid AS
contableoid, "
@@ -7419,6 +7421,7 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int
numTables)
i_indkey = PQfnumber(res, "indkey");
i_indisclustered = PQfnumber(res, "indisclustered");
i_indisreplident = PQfnumber(res, "indisreplident");
+ i_indnullsnotdistinct = PQfnumber(res, "indnullsnotdistinct");
i_contype = PQfnumber(res, "contype");
i_conname = PQfnumber(res, "conname");
i_condeferrable = PQfnumber(res, "condeferrable");
@@ -7460,6 +7463,7 @@ getIndexes(Archive *fout, TableInfo tblinfo[], int
numTables)
indxinfo[j].indkeys,
indxinfo[j].indnattrs);
indxinfo[j].indisclustered = (PQgetvalue(res, j,
i_indisclustered)[0] == 't');
indxinfo[j].indisreplident = (PQgetvalue(res, j,
i_indisreplident)[0] == 't');
+ indxinfo[j].indnullsnotdistinct = (PQgetvalue(res, j,
i_indnullsnotdistinct)[0] == 't');
indxinfo[j].parentidx = atooid(PQgetvalue(res, j,
i_parentidx));
indxinfo[j].partattaches = (SimplePtrList)
{
@@ -17069,8 +17073,11 @@ dumpConstraint(Archive *fout, const ConstraintInfo
*coninfo)
}
else
{
- appendPQExpBuffer(q, "%s (",
+ appendPQExpBuffer(q, "%s",
coninfo->contype ==
'p' ? "PRIMARY KEY" : "UNIQUE");
+ if (indxinfo->indnullsnotdistinct)
+ appendPQExpBuffer(q, " NULLS NOT DISTINCT");
+ appendPQExpBuffer(q, " (");
for (k = 0; k < indxinfo->indnkeyattrs; k++)
{
int indkey = (int)
indxinfo->indkeys[k];
diff --git a/src/bin/pg_dump/pg_dump.h b/src/bin/pg_dump/pg_dump.h
index f5e170e0db..25795a8df4 100644
--- a/src/bin/pg_dump/pg_dump.h
+++ b/src/bin/pg_dump/pg_dump.h
@@ -380,6 +380,7 @@ typedef struct _indxInfo
* contains
both key and nonkey attributes */
bool indisclustered;
bool indisreplident;
+ bool indnullsnotdistinct;
Oid parentidx; /* if a partition,
parent index OID */
SimplePtrList partattaches; /* if partitioned, partition attach objects
*/
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c
index 8333558bda..e6d07492c4 100644
--- a/src/bin/psql/describe.c
+++ b/src/bin/psql/describe.c
@@ -2438,6 +2438,11 @@ describeOneTableDetails(const char *schemaname,
else
appendPQExpBufferStr(&buf, "false AS
indisreplident,\n");
+ if (pset.sversion >= 150000)
+ appendPQExpBufferStr(&buf, "i.indnullsnotdistinct,\n");
+ else
+ appendPQExpBufferStr(&buf, "false AS
indnullsnotdistinct,\n");
+
appendPQExpBuffer(&buf, " a.amname, c2.relname, "
"pg_catalog.pg_get_expr(i.indpred, i.indrelid, true)\n"
"FROM pg_catalog.pg_index i,
pg_catalog.pg_class c, pg_catalog.pg_class c2, pg_catalog.pg_am a\n"
@@ -2462,14 +2467,20 @@ describeOneTableDetails(const char *schemaname,
char *deferrable = PQgetvalue(result, 0, 4);
char *deferred = PQgetvalue(result, 0, 5);
char *indisreplident = PQgetvalue(result, 0, 6);
- char *indamname = PQgetvalue(result, 0, 7);
- char *indtable = PQgetvalue(result, 0, 8);
- char *indpred = PQgetvalue(result, 0, 9);
+ char *indnullsnotdistinct = PQgetvalue(result, 0,
7);
+ char *indamname = PQgetvalue(result, 0, 8);
+ char *indtable = PQgetvalue(result, 0, 9);
+ char *indpred = PQgetvalue(result, 0, 10);
if (strcmp(indisprimary, "t") == 0)
printfPQExpBuffer(&tmpbuf, _("primary key, "));
else if (strcmp(indisunique, "t") == 0)
- printfPQExpBuffer(&tmpbuf, _("unique, "));
+ {
+ printfPQExpBuffer(&tmpbuf, _("unique"));
+ if (strcmp(indnullsnotdistinct, "t") == 0)
+ appendPQExpBufferStr(&tmpbuf, _(" nulls
not distinct"));
+ appendPQExpBuffer(&tmpbuf, _(", "));
+ }
else
resetPQExpBuffer(&tmpbuf);
appendPQExpBuffer(&tmpbuf, "%s, ", indamname);
@@ -2544,6 +2555,10 @@ describeOneTableDetails(const char *schemaname,
appendPQExpBufferStr(&buf, ", false AS
indisreplident");
if (pset.sversion >= 80000)
appendPQExpBufferStr(&buf, ",
c2.reltablespace");
+ if (pset.sversion >= 150000)
+ appendPQExpBufferStr(&buf, ",
i.indnullsnotdistinct");
+ else
+ appendPQExpBufferStr(&buf, ", false AS
indnullsnotdistinct");
appendPQExpBufferStr(&buf,
"\nFROM
pg_catalog.pg_class c, pg_catalog.pg_class c2, pg_catalog.pg_index i\n");
if (pset.sversion >= 90000)
@@ -2585,9 +2600,12 @@ describeOneTableDetails(const char *schemaname,
else if
(strcmp(PQgetvalue(result, i, 2), "t") == 0)
{
if
(strcmp(PQgetvalue(result, i, 7), "u") == 0)
-
appendPQExpBufferStr(&buf, " UNIQUE CONSTRAINT,");
+
appendPQExpBufferStr(&buf, " UNIQUE CONSTRAINT");
else
-
appendPQExpBufferStr(&buf, " UNIQUE,");
+
appendPQExpBufferStr(&buf, " UNIQUE");
+ if
(strcmp(PQgetvalue(result, i, 12), "t") == 0)
+
appendPQExpBufferStr(&buf, " NULLS NOT DISTINCT");
+
appendPQExpBufferStr(&buf, ",");
}
/* Everything after "USING" is
echoed verbatim */
diff --git a/src/include/catalog/pg_index.h b/src/include/catalog/pg_index.h
index a5a6075d4d..8c8300284e 100644
--- a/src/include/catalog/pg_index.h
+++ b/src/include/catalog/pg_index.h
@@ -34,6 +34,7 @@ CATALOG(pg_index,2610,IndexRelationId) BKI_SCHEMA_MACRO
int16 indnatts; /* total number of columns in
index */
int16 indnkeyatts; /* number of key columns in index */
bool indisunique; /* is this a unique index? */
+ bool indnullsnotdistinct; /* null treatment in unique
index */
bool indisprimary; /* is this index for primary key? */
bool indisexclusion; /* is this index for exclusion
constraint? */
bool indimmediate; /* is uniqueness enforced immediately?
*/
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 37cb4f3d59..c7765cc8e7 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -170,6 +170,7 @@ typedef struct IndexInfo
uint16 *ii_UniqueStrats; /* array with one entry per column */
Datum *ii_OpclassOptions; /* array with one entry per column */
bool ii_Unique;
+ bool ii_NullsNotDistinct;
bool ii_ReadyForInserts;
bool ii_Concurrent;
bool ii_BrokenHotChain;
diff --git a/src/include/nodes/makefuncs.h b/src/include/nodes/makefuncs.h
index 48a7ebfe45..aad5d141c3 100644
--- a/src/include/nodes/makefuncs.h
+++ b/src/include/nodes/makefuncs.h
@@ -96,7 +96,7 @@ extern List *make_ands_implicit(Expr *clause);
extern IndexInfo *makeIndexInfo(int numattrs, int numkeyattrs, Oid amoid,
List
*expressions, List *predicates,
- bool unique,
bool isready, bool concurrent);
+ bool unique,
bool nulls_not_distinct, bool isready, bool concurrent);
extern DefElem *makeDefElem(char *name, Node *arg, int location);
extern DefElem *makeDefElemExtended(char *nameSpace, char *name, Node *arg,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 7af13dee43..cdf285aa93 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2263,6 +2263,7 @@ typedef struct Constraint
char generated_when; /* ALWAYS or BY DEFAULT */
/* Fields used for unique constraints (UNIQUE and PRIMARY KEY): */
+ bool nulls_not_distinct; /* null treatment for UNIQUE
constraints */
List *keys; /* String nodes naming
referenced key
* column(s) */
List *including; /* String nodes naming referenced nonkey
@@ -2890,6 +2891,7 @@ typedef struct IndexStmt
SubTransactionId oldFirstRelfilenodeSubid; /*
rd_firstRelfilenodeSubid of
* oldNode */
bool unique; /* is index unique? */
+ bool nulls_not_distinct; /* null treatment for UNIQUE
constraints */
bool primary; /* is index a primary key? */
bool isconstraint; /* is it for a pkey/unique constraint?
*/
bool deferrable; /* is the constraint
DEFERRABLE? */
diff --git a/src/include/utils/tuplesort.h b/src/include/utils/tuplesort.h
index f94949370b..b30ca09598 100644
--- a/src/include/utils/tuplesort.h
+++ b/src/include/utils/tuplesort.h
@@ -208,6 +208,7 @@ extern Tuplesortstate *tuplesort_begin_cluster(TupleDesc
tupDesc,
extern Tuplesortstate *tuplesort_begin_index_btree(Relation heapRel,
Relation indexRel,
bool enforceUnique,
+
bool uniqueNullsNotDistinct,
int workMem, SortCoordinate coordinate,
bool randomAccess);
extern Tuplesortstate *tuplesort_begin_index_hash(Relation heapRel,
diff --git a/src/test/regress/expected/create_index.out
b/src/test/regress/expected/create_index.out
index 4750eac359..308818b7e1 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -1272,6 +1272,57 @@ SELECT count(*) FROM tenk1 WHERE stringu1 = 'TVAAAA';
DROP INDEX hash_tuplesort_idx;
RESET maintenance_work_mem;
--
+-- Test unique null behavior
+--
+CREATE TABLE unique_tbl (i int, t text);
+CREATE UNIQUE INDEX unique_idx1 ON unique_tbl (i) NULLS DISTINCT;
+CREATE UNIQUE INDEX unique_idx2 ON unique_tbl (i) NULLS NOT DISTINCT;
+INSERT INTO unique_tbl VALUES (1, 'one');
+INSERT INTO unique_tbl VALUES (2, 'two');
+INSERT INTO unique_tbl VALUES (3, 'three');
+INSERT INTO unique_tbl VALUES (4, 'four');
+INSERT INTO unique_tbl VALUES (5, 'one');
+INSERT INTO unique_tbl (t) VALUES ('six');
+INSERT INTO unique_tbl (t) VALUES ('seven'); -- error from unique_idx2
+ERROR: duplicate key value violates unique constraint "unique_idx2"
+DETAIL: Key (i)=(null) already exists.
+DROP INDEX unique_idx1, unique_idx2;
+INSERT INTO unique_tbl (t) VALUES ('seven');
+-- build indexes on filled table
+CREATE UNIQUE INDEX unique_idx3 ON unique_tbl (i) NULLS DISTINCT; -- ok
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT; -- error
+ERROR: could not create unique index "unique_idx4"
+DETAIL: Key (i)=(null) is duplicated.
+DELETE FROM unique_tbl WHERE t = 'seven';
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT; -- ok
now
+\d unique_idx3
+ Index "public.unique_idx3"
+ Column | Type | Key? | Definition
+--------+---------+------+------------
+ i | integer | yes | i
+unique, btree, for table "public.unique_tbl"
+
+\d unique_idx4
+ Index "public.unique_idx4"
+ Column | Type | Key? | Definition
+--------+---------+------+------------
+ i | integer | yes | i
+unique nulls not distinct, btree, for table "public.unique_tbl"
+
+SELECT pg_get_indexdef('unique_idx3'::regclass);
+ pg_get_indexdef
+----------------------------------------------------------------------
+ CREATE UNIQUE INDEX unique_idx3 ON public.unique_tbl USING btree (i)
+(1 row)
+
+SELECT pg_get_indexdef('unique_idx4'::regclass);
+ pg_get_indexdef
+-----------------------------------------------------------------------------------------
+ CREATE UNIQUE INDEX unique_idx4 ON public.unique_tbl USING btree (i) NULLS
NOT DISTINCT
+(1 row)
+
+DROP TABLE unique_tbl;
+--
-- Test functional index
--
CREATE TABLE func_index_heap (f1 text, f2 text);
diff --git a/src/test/regress/input/constraints.source
b/src/test/regress/input/constraints.source
index 6bb7648321..2dae540cfc 100644
--- a/src/test/regress/input/constraints.source
+++ b/src/test/regress/input/constraints.source
@@ -301,6 +301,20 @@ SELECT * FROM UNIQUE_TBL;
DROP TABLE UNIQUE_TBL;
+CREATE TABLE UNIQUE_TBL (i int UNIQUE NULLS NOT DISTINCT, t text);
+
+INSERT INTO UNIQUE_TBL VALUES (1, 'one');
+INSERT INTO UNIQUE_TBL VALUES (2, 'two');
+INSERT INTO UNIQUE_TBL VALUES (1, 'three');
+INSERT INTO UNIQUE_TBL VALUES (4, 'four');
+INSERT INTO UNIQUE_TBL VALUES (5, 'one');
+INSERT INTO UNIQUE_TBL (t) VALUES ('six');
+INSERT INTO UNIQUE_TBL (t) VALUES ('seven');
+
+SELECT * FROM UNIQUE_TBL;
+
+DROP TABLE UNIQUE_TBL;
+
CREATE TABLE UNIQUE_TBL (i int, t text,
UNIQUE(i,t));
diff --git a/src/test/regress/output/constraints.source
b/src/test/regress/output/constraints.source
index eff793cc3d..266baa985c 100644
--- a/src/test/regress/output/constraints.source
+++ b/src/test/regress/output/constraints.source
@@ -441,6 +441,29 @@ SELECT * FROM UNIQUE_TBL;
6 | six-upsert-insert
(7 rows)
+DROP TABLE UNIQUE_TBL;
+CREATE TABLE UNIQUE_TBL (i int UNIQUE NULLS NOT DISTINCT, t text);
+INSERT INTO UNIQUE_TBL VALUES (1, 'one');
+INSERT INTO UNIQUE_TBL VALUES (2, 'two');
+INSERT INTO UNIQUE_TBL VALUES (1, 'three');
+ERROR: duplicate key value violates unique constraint "unique_tbl_i_key"
+DETAIL: Key (i)=(1) already exists.
+INSERT INTO UNIQUE_TBL VALUES (4, 'four');
+INSERT INTO UNIQUE_TBL VALUES (5, 'one');
+INSERT INTO UNIQUE_TBL (t) VALUES ('six');
+INSERT INTO UNIQUE_TBL (t) VALUES ('seven');
+ERROR: duplicate key value violates unique constraint "unique_tbl_i_key"
+DETAIL: Key (i)=(null) already exists.
+SELECT * FROM UNIQUE_TBL;
+ i | t
+---+------
+ 1 | one
+ 2 | two
+ 4 | four
+ 5 | one
+ | six
+(5 rows)
+
DROP TABLE UNIQUE_TBL;
CREATE TABLE UNIQUE_TBL (i int, t text,
UNIQUE(i,t));
diff --git a/src/test/regress/sql/create_index.sql
b/src/test/regress/sql/create_index.sql
index 22209b0691..49b4d0caa9 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -387,6 +387,42 @@ CREATE INDEX hash_tuplesort_idx ON tenk1 USING hash
(stringu1 name_ops) WITH (fi
RESET maintenance_work_mem;
+--
+-- Test unique null behavior
+--
+CREATE TABLE unique_tbl (i int, t text);
+
+CREATE UNIQUE INDEX unique_idx1 ON unique_tbl (i) NULLS DISTINCT;
+CREATE UNIQUE INDEX unique_idx2 ON unique_tbl (i) NULLS NOT DISTINCT;
+
+INSERT INTO unique_tbl VALUES (1, 'one');
+INSERT INTO unique_tbl VALUES (2, 'two');
+INSERT INTO unique_tbl VALUES (3, 'three');
+INSERT INTO unique_tbl VALUES (4, 'four');
+INSERT INTO unique_tbl VALUES (5, 'one');
+INSERT INTO unique_tbl (t) VALUES ('six');
+INSERT INTO unique_tbl (t) VALUES ('seven'); -- error from unique_idx2
+
+DROP INDEX unique_idx1, unique_idx2;
+
+INSERT INTO unique_tbl (t) VALUES ('seven');
+
+-- build indexes on filled table
+CREATE UNIQUE INDEX unique_idx3 ON unique_tbl (i) NULLS DISTINCT; -- ok
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT; -- error
+
+DELETE FROM unique_tbl WHERE t = 'seven';
+
+CREATE UNIQUE INDEX unique_idx4 ON unique_tbl (i) NULLS NOT DISTINCT; -- ok
now
+
+\d unique_idx3
+\d unique_idx4
+SELECT pg_get_indexdef('unique_idx3'::regclass);
+SELECT pg_get_indexdef('unique_idx4'::regclass);
+
+DROP TABLE unique_tbl;
+
+
--
-- Test functional index
--
--
2.33.0
