Add bytea_agg, parallel to string_agg.

Pavel Stehule

doc/src/sgml/func.sgml

@@ -10908,6 +10908,24 @@ SELECT NULLIF(value, '(none)') ...
       <entry>true if at least one input value is true, otherwise false</entry>
      </row>
 
+     <row>
+      <entry>
+       <indexterm>
+        <primary>bytea_agg</primary>
+       </indexterm>
+       <function>
+         bytea_agg(<replaceable class="parameter">expression</replaceable>)
+       </function>
+      </entry>
+      <entry>
+       <type>bytea</type>
+      </entry>
+      <entry>
+       <type>bytea</type>
+      </entry>
+      <entry>input values concatenated into a bytea</entry>
+     </row>
+
      <row>
       <entry>
        <indexterm>

src/backend/utils/adt/varlena.c

@@ -396,6 +396,53 @@ byteasend(PG_FUNCTION_ARGS)
 	PG_RETURN_BYTEA_P(vlena);
 }
 
+Datum
+bytea_agg_transfn(PG_FUNCTION_ARGS)
+{
+	StringInfo	state;
+
+	state = PG_ARGISNULL(0) ? NULL : (StringInfo) PG_GETARG_POINTER(0);
+
+	/* Append the value unless null. */
+	if (!PG_ARGISNULL(1))
+	{
+		bytea	   *value = PG_GETARG_BYTEA_PP(1);
+
+		if (state == NULL)
+			state = makeStringAggState(fcinfo);
+
+		appendBinaryStringInfo(state, VARDATA_ANY(value), VARSIZE_ANY_EXHDR(value));
+	}
+
+	/*
+	 * The transition type for bytea_agg() is declared to be "internal",
+	 * which is a pass-by-value type the same size as a pointer.
+	 */
+	PG_RETURN_POINTER(state);
+}
+
+Datum
+bytea_agg_finalfn(PG_FUNCTION_ARGS)
+{
+	StringInfo	state;
+
+	/* cannot be called directly because of internal-type argument */
+	Assert(AggCheckCallContext(fcinfo, NULL));
+
+	state = PG_ARGISNULL(0) ? NULL : (StringInfo) PG_GETARG_POINTER(0);
+
+	if (state != NULL)
+	{
+		bytea	   *result;
+
+		result = (bytea *) palloc(state->len + VARHDRSZ);
+		SET_VARSIZE(result, state->len + VARHDRSZ);
+		memcpy(VARDATA(result), state->data, state->len);
+		PG_RETURN_BYTEA_P(result);
+	}
+	else
+		PG_RETURN_NULL();
+}
 
 /*
  *		textin			- converts "..." to internal representation

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201112221
+#define CATALOG_VERSION_NO	201112231
 
 #endif

src/include/catalog/pg_aggregate.h

@@ -226,6 +226,9 @@ DATA(insert ( 2335	array_agg_transfn	array_agg_finalfn		0	2281	_null_ ));
 /* text */
 DATA(insert ( 3538	string_agg_transfn	string_agg_finalfn		0	2281	_null_ ));
 
+/* bytea */
+DATA(insert ( 3545	bytea_agg_transfn	bytea_agg_finalfn		0	2281	_null_ ));
+
 /*
  * prototypes for functions in pg_aggregate.c
  */

src/include/catalog/pg_proc.h

@@ -2403,12 +2403,19 @@ DATA(insert OID = 2816 (  float8_covar_samp			PGNSP PGUID 12 1 0 0 0 f f f t f i
 DESCR("aggregate final function");
 DATA(insert OID = 2817 (  float8_corr				PGNSP PGUID 12 1 0 0 0 f f f t f i 1 0 701 "1022" _null_ _null_ _null_ _null_ float8_corr _null_ _null_ _null_ ));
 DESCR("aggregate final function");
+
 DATA(insert OID = 3535 (  string_agg_transfn		PGNSP PGUID 12 1 0 0 0 f f f f f i 3 0 2281 "2281 25 25" _null_ _null_ _null_ _null_ string_agg_transfn _null_ _null_ _null_ ));
 DESCR("aggregate transition function");
 DATA(insert OID = 3536 (  string_agg_finalfn		PGNSP PGUID 12 1 0 0 0 f f f f f i 1 0 25 "2281" _null_ _null_ _null_ _null_ string_agg_finalfn _null_ _null_ _null_ ));
 DESCR("aggregate final function");
 DATA(insert OID = 3538 (  string_agg				PGNSP PGUID 12 1 0 0 0 t f f f f i 2 0 25 "25 25" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
 DESCR("concatenate aggregate input into a string");
+DATA(insert OID = 3543 (  bytea_agg_transfn		PGNSP PGUID 12 1 0 0 0 f f f f f i 2 0 2281 "2281 17" _null_ _null_ _null_ _null_ bytea_agg_transfn _null_ _null_ _null_ ));
+DESCR("aggregate transition function");
+DATA(insert OID = 3544 (  bytea_agg_finalfn		PGNSP PGUID 12 1 0 0 0 f f f f f i 1 0 17 "2281" _null_ _null_ _null_ _null_ bytea_agg_finalfn _null_ _null_ _null_ ));
+DESCR("aggregate final function");
+DATA(insert OID = 3545 (  bytea_agg				PGNSP PGUID 12 1 0 0 0 t f f f f i 1 0 17 "17" _null_ _null_ _null_ _null_ aggregate_dummy _null_ _null_ _null_ ));
+DESCR("concatenate aggregate input into a bytea");
 
 /* To ASCII conversion */
 DATA(insert OID = 1845 ( to_ascii	PGNSP PGUID 12 1 0 0 0 f f f t f i 1 0 25 "25" _null_ _null_ _null_ _null_	to_ascii_default _null_ _null_ _null_ ));

src/include/utils/builtins.h

@@ -769,6 +769,8 @@ extern Datum unknownsend(PG_FUNCTION_ARGS);
 
 extern Datum pg_column_size(PG_FUNCTION_ARGS);
 
+extern Datum bytea_agg_transfn(PG_FUNCTION_ARGS);
+extern Datum bytea_agg_finalfn(PG_FUNCTION_ARGS);
 extern Datum string_agg_transfn(PG_FUNCTION_ARGS);
 extern Datum string_agg_finalfn(PG_FUNCTION_ARGS);
 

src/test/regress/expected/aggregates.out

@@ -1061,3 +1061,26 @@ select string_agg(distinct f1::text, ',' order by f1::text) from varchar_tbl;  -
  a,ab,abcd
 (1 row)
 
+-- bytea_agg tests
+create table bytea_test_table(v bytea);
+select bytea_agg(v) from bytea_test_table;
+ bytea_agg 
+-----------
+ 
+(1 row)
+
+insert into bytea_test_table values(decode('ff','hex'));
+select bytea_agg(v) from bytea_test_table;
+ bytea_agg 
+-----------
+ \xff
+(1 row)
+
+insert into bytea_test_table values(decode('aa','hex'));
+select bytea_agg(v) from bytea_test_table;
+ bytea_agg 
+-----------
+ \xffaa
+(1 row)
+
+drop table bytea_test_table;

src/test/regress/sql/aggregates.sql

@@ -416,3 +416,18 @@ select string_agg(distinct f1, ',' order by f1) from varchar_tbl;  -- ok
 select string_agg(distinct f1::text, ',' order by f1) from varchar_tbl;  -- not ok
 select string_agg(distinct f1, ',' order by f1::text) from varchar_tbl;  -- not ok
 select string_agg(distinct f1::text, ',' order by f1::text) from varchar_tbl;  -- ok
+
+-- bytea_agg tests
+create table bytea_test_table(v bytea);
+
+select bytea_agg(v) from bytea_test_table;
+
+insert into bytea_test_table values(decode('ff','hex'));
+
+select bytea_agg(v) from bytea_test_table;
+
+insert into bytea_test_table values(decode('aa','hex'));
+
+select bytea_agg(v) from bytea_test_table;
+
+drop table bytea_test_table;