Extend pg_publication_tables to display column list and row filter.

Commit 923def9a53 and 52e4f0cd47 allowed to specify column lists and row
filters for publication tables. This commit extends the
pg_publication_tables view and pg_get_publication_tables function to
display that information.

This information will be useful to users and we also need this for the
later commit that prohibits combining multiple publications with different
column lists for the same table.

Author: Hou Zhijie
Reviewed By: Amit Kapila, Alvaro Herrera, Shi Yu, Takamichi Osumi
Discussion: https://postgr.es/m/202204251548.mudq7jbqnh7r@alvherre.pgsql

doc/src/sgml/catalogs.sgml

@@ -9691,7 +9691,7 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
 
      <row>
       <entry><link linkend="view-pg-publication-tables"><structname>pg_publication_tables</structname></link></entry>
-      <entry>publications and their associated tables</entry>
+      <entry>publications and information of their associated tables</entry>
      </row>
 
      <row>
@@ -11635,8 +11635,8 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
 
   <para>
    The view <structname>pg_publication_tables</structname> provides
-   information about the mapping between publications and the tables they
-   contain.  Unlike the underlying catalog
+   information about the mapping between publications and information of
+   tables they contain.  Unlike the underlying catalog
    <link linkend="catalog-pg-publication-rel"><structname>pg_publication_rel</structname></link>,
    this view expands publications defined as <literal>FOR ALL TABLES</literal>
    and <literal>FOR ALL TABLES IN SCHEMA</literal>, so for such publications
@@ -11687,6 +11687,27 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts ppx
        Name of table
       </para></entry>
      </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>attnames</structfield> <type>name[]</type>
+       (references <link linkend="catalog-pg-attribute"><structname>pg_attribute</structname></link>.<structfield>attname</structfield>)
+      </para>
+      <para>
+       Names of table columns included in the publication. This contains all
+       the columns of the table when the user didn't specify the column list
+       for the table.
+      </para></entry>
+     </row>
+
+     <row>
+      <entry role="catalog_table_entry"><para role="column_definition">
+       <structfield>rowfilter</structfield> <type>text</type>
+      </para>
+      <para>
+       Expression for the table's publication qualifying condition
+      </para></entry>
+     </row>
     </tbody>
    </tgroup>
   </table>

src/backend/catalog/pg_publication.c

@@ -1077,11 +1077,12 @@ get_publication_name(Oid pubid, bool missing_ok)
 }
 
 /*
- * Returns Oids of tables in a publication.
+ * Returns information of tables in a publication.
  */
 Datum
 pg_get_publication_tables(PG_FUNCTION_ARGS)
 {
+#define NUM_PUBLICATOIN_TABLES_ELEM	3
 	FuncCallContext *funcctx;
 	char	   *pubname = text_to_cstring(PG_GETARG_TEXT_PP(0));
 	Publication *publication;
@@ -1090,6 +1091,7 @@ pg_get_publication_tables(PG_FUNCTION_ARGS)
 	/* stuff done only on the first call of the function */
 	if (SRF_IS_FIRSTCALL())
 	{
+		TupleDesc	tupdesc;
 		MemoryContext oldcontext;
 
 		/* create a function context for cross-call persistence */
@@ -1136,6 +1138,16 @@ pg_get_publication_tables(PG_FUNCTION_ARGS)
 				tables = filter_partitions(tables);
 		}
 
+		/* Construct a tuple descriptor for the result rows. */
+		tupdesc = CreateTemplateTupleDesc(NUM_PUBLICATOIN_TABLES_ELEM);
+		TupleDescInitEntry(tupdesc, (AttrNumber) 1, "relid",
+						   OIDOID, -1, 0);
+		TupleDescInitEntry(tupdesc, (AttrNumber) 2, "attrs",
+						   INT2VECTOROID, -1, 0);
+		TupleDescInitEntry(tupdesc, (AttrNumber) 3, "qual",
+						   PG_NODE_TREEOID, -1, 0);
+
+		funcctx->tuple_desc = BlessTupleDesc(tupdesc);
 		funcctx->user_fctx = (void *) tables;
 
 		MemoryContextSwitchTo(oldcontext);
@@ -1147,9 +1159,47 @@ pg_get_publication_tables(PG_FUNCTION_ARGS)
 
 	if (funcctx->call_cntr < list_length(tables))
 	{
+		HeapTuple	pubtuple = NULL;
+		HeapTuple	rettuple;
 		Oid			relid = list_nth_oid(tables, funcctx->call_cntr);
+		Datum		values[NUM_PUBLICATOIN_TABLES_ELEM];
+		bool		nulls[NUM_PUBLICATOIN_TABLES_ELEM];
+
+		/*
+		 * Form tuple with appropriate data.
+		 */
+		MemSet(nulls, 0, sizeof(nulls));
+		MemSet(values, 0, sizeof(values));
+
+		publication = GetPublicationByName(pubname, false);
+
+		values[0] = ObjectIdGetDatum(relid);
+
+		pubtuple = SearchSysCacheCopy2(PUBLICATIONRELMAP,
+									   ObjectIdGetDatum(relid),
+									   ObjectIdGetDatum(publication->oid));
+
+		if (HeapTupleIsValid(pubtuple))
+		{
+			/* Lookup the column list attribute. */
+			values[1] = SysCacheGetAttr(PUBLICATIONRELMAP, pubtuple,
+										Anum_pg_publication_rel_prattrs,
+										&(nulls[1]));
+
+			/* Null indicates no filter. */
+			values[2] = SysCacheGetAttr(PUBLICATIONRELMAP, pubtuple,
+										Anum_pg_publication_rel_prqual,
+										&(nulls[2]));
+		}
+		else
+		{
+			nulls[1] = true;
+			nulls[2] = true;
+		}
+
+		rettuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
 
-		SRF_RETURN_NEXT(funcctx, ObjectIdGetDatum(relid));
+		SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(rettuple));
 	}
 
 	SRF_RETURN_DONE(funcctx);

src/backend/catalog/system_views.sql

@@ -368,7 +368,15 @@ CREATE VIEW pg_publication_tables AS
     SELECT
         P.pubname AS pubname,
         N.nspname AS schemaname,
-        C.relname AS tablename
+        C.relname AS tablename,
+        ( SELECT array_agg(a.attname ORDER BY a.attnum)
+          FROM unnest(CASE WHEN GPT.attrs IS NOT NULL THEN GPT.attrs
+                      ELSE (SELECT array_agg(g) FROM generate_series(1, C.relnatts) g)
+                      END) k
+               JOIN pg_attribute a
+                    ON (a.attrelid = GPT.relid AND a.attnum = k)
+        ) AS attnames,
+        pg_get_expr(GPT.qual, GPT.relid) AS rowfilter
     FROM pg_publication P,
          LATERAL pg_get_publication_tables(P.pubname) GPT,
          pg_class C JOIN pg_namespace N ON (N.oid = C.relnamespace)

src/backend/replication/logical/tablesync.c

@@ -795,15 +795,12 @@ fetch_remote_table_info(char *nspname, char *relname,
 		resetStringInfo(&cmd);
 		appendStringInfo(&cmd,
 						 "SELECT DISTINCT unnest"
-						 "  FROM pg_publication p"
-						 "  LEFT OUTER JOIN pg_publication_rel pr"
-						 "       ON (p.oid = pr.prpubid AND pr.prrelid = %u)"
-						 "  LEFT OUTER JOIN unnest(pr.prattrs) ON TRUE,"
+						 "  FROM pg_publication p,"
 						 "  LATERAL pg_get_publication_tables(p.pubname) gpt"
+						 "  LEFT OUTER JOIN unnest(gpt.attrs) ON TRUE"
 						 " WHERE gpt.relid = %u"
 						 "   AND p.pubname IN ( %s )",
 						 lrel->remoteid,
-						 lrel->remoteid,
 						 pub_names.data);
 
 		pubres = walrcv_exec(LogRepWorkerWalRcvConn, cmd.data,
@@ -965,15 +962,12 @@ fetch_remote_table_info(char *nspname, char *relname,
 		/* Check for row filters. */
 		resetStringInfo(&cmd);
 		appendStringInfo(&cmd,
-						 "SELECT DISTINCT pg_get_expr(pr.prqual, pr.prrelid)"
-						 "  FROM pg_publication p"
-						 "  LEFT OUTER JOIN pg_publication_rel pr"
-						 "       ON (p.oid = pr.prpubid AND pr.prrelid = %u),"
+						 "SELECT DISTINCT pg_get_expr(gpt.qual, gpt.relid)"
+						 "  FROM pg_publication p,"
 						 "  LATERAL pg_get_publication_tables(p.pubname) gpt"
 						 " WHERE gpt.relid = %u"
 						 "   AND p.pubname IN ( %s )",
 						 lrel->remoteid,
-						 lrel->remoteid,
 						 pub_names.data);
 
 		res = walrcv_exec(LogRepWorkerWalRcvConn, cmd.data, 1, qualRow);

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202205131
+#define CATALOG_VERSION_NO	202205191
 
 #endif

src/include/catalog/pg_proc.dat

@@ -11673,11 +11673,11 @@
   prosrc => 'pg_show_replication_origin_status' },
 
 # publications
-{ oid => '6119', descr => 'get OIDs of tables in a publication',
+{ oid => '6119', descr => 'get information of tables in a publication',
   proname => 'pg_get_publication_tables', prorows => '1000', proretset => 't',
-  provolatile => 's', prorettype => 'oid', proargtypes => 'text',
-  proallargtypes => '{text,oid}', proargmodes => '{i,o}',
-  proargnames => '{pubname,relid}', prosrc => 'pg_get_publication_tables' },
+  provolatile => 's', prorettype => 'record', proargtypes => 'text',
+  proallargtypes => '{text,oid,int2vector,pg_node_tree}', proargmodes => '{i,o,o,o}',
+  proargnames => '{pubname,relid,attrs,qual}', prosrc => 'pg_get_publication_tables' },
 { oid => '6121',
   descr => 'returns whether a relation can be part of a publication',
   proname => 'pg_relation_is_publishable', provolatile => 's',

src/test/regress/expected/publication.out

@@ -1585,52 +1585,52 @@ CREATE TABLE sch2.tbl1_part1 PARTITION OF sch1.tbl1 FOR VALUES FROM (1) to (10);
 -- Schema publication that does not include the schema that has the parent table
 CREATE PUBLICATION pub FOR ALL TABLES IN SCHEMA sch2 WITH (PUBLISH_VIA_PARTITION_ROOT=1);
 SELECT * FROM pg_publication_tables;
- pubname | schemaname | tablename  
----------+------------+------------
- pub     | sch2       | tbl1_part1
+ pubname | schemaname | tablename  | attnames | rowfilter 
+---------+------------+------------+----------+-----------
+ pub     | sch2       | tbl1_part1 | {a}      | 
 (1 row)
 
 DROP PUBLICATION pub;
 -- Table publication that does not include the parent table
 CREATE PUBLICATION pub FOR TABLE sch2.tbl1_part1 WITH (PUBLISH_VIA_PARTITION_ROOT=1);
 SELECT * FROM pg_publication_tables;
- pubname | schemaname | tablename  
----------+------------+------------
- pub     | sch2       | tbl1_part1
+ pubname | schemaname | tablename  | attnames | rowfilter 
+---------+------------+------------+----------+-----------
+ pub     | sch2       | tbl1_part1 | {a}      | 
 (1 row)
 
 -- Table publication that includes both the parent table and the child table
 ALTER PUBLICATION pub ADD TABLE sch1.tbl1;
 SELECT * FROM pg_publication_tables;
- pubname | schemaname | tablename 
----------+------------+-----------
- pub     | sch1       | tbl1
+ pubname | schemaname | tablename | attnames | rowfilter 
+---------+------------+-----------+----------+-----------
+ pub     | sch1       | tbl1      | {a}      | 
 (1 row)
 
 DROP PUBLICATION pub;
 -- Schema publication that does not include the schema that has the parent table
 CREATE PUBLICATION pub FOR ALL TABLES IN SCHEMA sch2 WITH (PUBLISH_VIA_PARTITION_ROOT=0);
 SELECT * FROM pg_publication_tables;
- pubname | schemaname | tablename  
----------+------------+------------
- pub     | sch2       | tbl1_part1
+ pubname | schemaname | tablename  | attnames | rowfilter 
+---------+------------+------------+----------+-----------
+ pub     | sch2       | tbl1_part1 | {a}      | 
 (1 row)
 
 DROP PUBLICATION pub;
 -- Table publication that does not include the parent table
 CREATE PUBLICATION pub FOR TABLE sch2.tbl1_part1 WITH (PUBLISH_VIA_PARTITION_ROOT=0);
 SELECT * FROM pg_publication_tables;
- pubname | schemaname | tablename  
----------+------------+------------
- pub     | sch2       | tbl1_part1
+ pubname | schemaname | tablename  | attnames | rowfilter 
+---------+------------+------------+----------+-----------
+ pub     | sch2       | tbl1_part1 | {a}      | 
 (1 row)
 
 -- Table publication that includes both the parent table and the child table
 ALTER PUBLICATION pub ADD TABLE sch1.tbl1;
 SELECT * FROM pg_publication_tables;
- pubname | schemaname | tablename  
----------+------------+------------
- pub     | sch2       | tbl1_part1
+ pubname | schemaname | tablename  | attnames | rowfilter 
+---------+------------+------------+----------+-----------
+ pub     | sch2       | tbl1_part1 | {a}      | 
 (1 row)
 
 DROP PUBLICATION pub;
@@ -1643,9 +1643,9 @@ CREATE TABLE sch1.tbl1_part3 (a int) PARTITION BY RANGE(a);
 ALTER TABLE sch1.tbl1 ATTACH PARTITION sch1.tbl1_part3 FOR VALUES FROM (20) to (30);
 CREATE PUBLICATION pub FOR ALL TABLES IN SCHEMA sch1 WITH (PUBLISH_VIA_PARTITION_ROOT=1);
 SELECT * FROM pg_publication_tables;
- pubname | schemaname | tablename 
----------+------------+-----------
- pub     | sch1       | tbl1
+ pubname | schemaname | tablename | attnames | rowfilter 
+---------+------------+-----------+----------+-----------
+ pub     | sch1       | tbl1      | {a}      | 
 (1 row)
 
 RESET client_min_messages;

src/test/regress/expected/rules.out

@@ -1437,9 +1437,18 @@ pg_prepared_xacts| SELECT p.transaction,
      LEFT JOIN pg_database d ON ((p.dbid = d.oid)));
 pg_publication_tables| SELECT p.pubname,
     n.nspname AS schemaname,
-    c.relname AS tablename
+    c.relname AS tablename,
+    ( SELECT array_agg(a.attname ORDER BY a.attnum) AS array_agg
+           FROM (unnest(
+                CASE
+                    WHEN (gpt.attrs IS NOT NULL) THEN (gpt.attrs)::integer[]
+                    ELSE ( SELECT array_agg(g.g) AS array_agg
+                       FROM generate_series(1, (c.relnatts)::integer) g(g))
+                END) k(k)
+             JOIN pg_attribute a ON (((a.attrelid = gpt.relid) AND (a.attnum = k.k))))) AS attnames,
+    pg_get_expr(gpt.qual, gpt.relid) AS rowfilter
    FROM pg_publication p,
-    LATERAL pg_get_publication_tables((p.pubname)::text) gpt(relid),
+    LATERAL pg_get_publication_tables((p.pubname)::text) gpt(relid, attrs, qual),
     (pg_class c
      JOIN pg_namespace n ON ((n.oid = c.relnamespace)))
   WHERE (c.oid = gpt.relid);