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Implement RETURN QUERY for PL/PgSQL. This provides some convenient syntax

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sugar for PL/PgSQL set-returning functions that want to return the result
of evaluating a query; it should also be more efficient than repeated
RETURN NEXT statements. Based on an earlier patch from Pavel Stehule.
This commit is contained in:
Neil Conway
2007-07-25 04:19:09 +00:00
parent 507b53c833
commit b2b9b4d59c
8 changed files with 236 additions and 37 deletions
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28
src/pl/plpgsql/src/gram.y
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.104 2007/07/16 17:01:10 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/gram.y,v 1.105 2007/07/25 04:19:08 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@ -32,6 +32,7 @@ static PLpgSQL_stmt *make_execsql_stmt(const char *sqlstart, int lineno);
static PLpgSQL_stmt_fetch *read_fetch_direction(void);
static PLpgSQL_stmt *make_return_stmt(int lineno);
static PLpgSQL_stmt *make_return_next_stmt(int lineno);
static PLpgSQL_stmt *make_return_query_stmt(int lineno);
static void check_assignable(PLpgSQL_datum *datum);
static void read_into_target(PLpgSQL_rec **rec, PLpgSQL_row **row,
bool *strict);
@ -187,6 +188,7 @@ static void check_labels(const char *start_label,
%token K_NULL
%token K_OPEN
%token K_OR
%token K_QUERY
%token K_PERFORM
%token K_ROW_COUNT
%token K_RAISE
@ -1171,6 +1173,10 @@ stmt_return : K_RETURN lno
{
$$ = make_return_next_stmt($2);
}
else if (tok == K_QUERY)
{
$$ = make_return_query_stmt($2);
}
else
{
plpgsql_push_back_token(tok);
@ -2104,7 +2110,8 @@ make_return_stmt(int lineno)
if (plpgsql_curr_compile->fn_retset)
{
if (yylex() != ';')
yyerror("RETURN cannot have a parameter in function returning set; use RETURN NEXT");
yyerror("RETURN cannot have a parameter in function "
"returning set; use RETURN NEXT or RETURN QUERY");
}
else if (plpgsql_curr_compile->out_param_varno >= 0)
{
@ -2200,6 +2207,23 @@ make_return_next_stmt(int lineno)
}
static PLpgSQL_stmt *
make_return_query_stmt(int lineno)
{
PLpgSQL_stmt_return_query *new;
if (!plpgsql_curr_compile->fn_retset)
yyerror("cannot use RETURN QUERY in a non-SETOF function");
new = palloc0(sizeof(PLpgSQL_stmt_return_query));
new->cmd_type = PLPGSQL_STMT_RETURN_QUERY;
new->lineno = lineno;
new->query = read_sql_construct(';', 0, ")", "", false, true, NULL);
return (PLpgSQL_stmt *) new;
}
static void
check_assignable(PLpgSQL_datum *datum)
{

61
src/pl/plpgsql/src/pl_exec.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.198 2007/07/15 02:15:04 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_exec.c,v 1.199 2007/07/25 04:19:08 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@ -105,6 +105,8 @@ static int exec_stmt_return(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return *stmt);
static int exec_stmt_return_next(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return_next *stmt);
static int exec_stmt_return_query(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return_query *stmt);
static int exec_stmt_raise(PLpgSQL_execstate *estate,
PLpgSQL_stmt_raise *stmt);
static int exec_stmt_execsql(PLpgSQL_execstate *estate,
@ -1244,6 +1246,10 @@ exec_stmt(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
rc = exec_stmt_return_next(estate, (PLpgSQL_stmt_return_next *) stmt);
break;
case PLPGSQL_STMT_RETURN_QUERY:
rc = exec_stmt_return_query(estate, (PLpgSQL_stmt_return_query *) stmt);
break;
case PLPGSQL_STMT_RAISE:
rc = exec_stmt_raise(estate, (PLpgSQL_stmt_raise *) stmt);
break;
@ -2137,6 +2143,59 @@ exec_stmt_return_next(PLpgSQL_execstate *estate,
return PLPGSQL_RC_OK;
}
/* ----------
* exec_stmt_return_query Evaluate a query and add it to the
* list of tuples returned by the current
* SRF.
* ----------
*/
static int
exec_stmt_return_query(PLpgSQL_execstate *estate,
PLpgSQL_stmt_return_query *stmt)
{
Portal portal;
if (!estate->retisset)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("cannot use RETURN QUERY in a non-SETOF function")));
if (estate->tuple_store == NULL)
exec_init_tuple_store(estate);
exec_run_select(estate, stmt->query, 0, &portal);
if (!compatible_tupdesc(estate->rettupdesc, portal->tupDesc))
ereport(ERROR,
(errcode(ERRCODE_DATATYPE_MISMATCH),
errmsg("structure of query does not match function result type")));
while (true)
{
MemoryContext old_cxt;
int i;
SPI_cursor_fetch(portal, true, 50);
if (SPI_processed == 0)
break;
old_cxt = MemoryContextSwitchTo(estate->tuple_store_cxt);
for (i = 0; i < SPI_processed; i++)
{
HeapTuple tuple = SPI_tuptable->vals[i];
tuplestore_puttuple(estate->tuple_store, tuple);
}
MemoryContextSwitchTo(old_cxt);
SPI_freetuptable(SPI_tuptable);
}
SPI_freetuptable(SPI_tuptable);
SPI_cursor_close(portal);
return PLPGSQL_RC_OK;
}
static void
exec_init_tuple_store(PLpgSQL_execstate *estate)
{

17
src/pl/plpgsql/src/pl_funcs.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.62 2007/07/20 16:23:34 petere Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/pl_funcs.c,v 1.63 2007/07/25 04:19:08 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@ -443,6 +443,8 @@ plpgsql_stmt_typename(PLpgSQL_stmt *stmt)
return "RETURN";
case PLPGSQL_STMT_RETURN_NEXT:
return "RETURN NEXT";
case PLPGSQL_STMT_RETURN_QUERY:
return "RETURN QUERY";
case PLPGSQL_STMT_RAISE:
return "RAISE";
case PLPGSQL_STMT_EXECSQL:
@ -484,6 +486,7 @@ static void dump_fors(PLpgSQL_stmt_fors *stmt);
static void dump_exit(PLpgSQL_stmt_exit *stmt);
static void dump_return(PLpgSQL_stmt_return *stmt);
static void dump_return_next(PLpgSQL_stmt_return_next *stmt);
static void dump_return_query(PLpgSQL_stmt_return_query *stmt);
static void dump_raise(PLpgSQL_stmt_raise *stmt);
static void dump_execsql(PLpgSQL_stmt_execsql *stmt);
static void dump_dynexecute(PLpgSQL_stmt_dynexecute *stmt);
@ -542,6 +545,9 @@ dump_stmt(PLpgSQL_stmt *stmt)
case PLPGSQL_STMT_RETURN_NEXT:
dump_return_next((PLpgSQL_stmt_return_next *) stmt);
break;
case PLPGSQL_STMT_RETURN_QUERY:
dump_return_query((PLpgSQL_stmt_return_query *) stmt);
break;
case PLPGSQL_STMT_RAISE:
dump_raise((PLpgSQL_stmt_raise *) stmt);
break;
@ -878,6 +884,15 @@ dump_return_next(PLpgSQL_stmt_return_next *stmt)
printf("\n");
}
static void
dump_return_query(PLpgSQL_stmt_return_query *stmt)
{
dump_ind();
printf("RETURN QUERY ");
dump_expr(stmt->query);
printf("\n");
}
static void
dump_raise(PLpgSQL_stmt_raise *stmt)
{

10
src/pl/plpgsql/src/plpgsql.h
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.90 2007/07/16 17:01:11 tgl Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/plpgsql.h,v 1.91 2007/07/25 04:19:09 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@ -83,6 +83,7 @@ enum
PLPGSQL_STMT_EXIT,
PLPGSQL_STMT_RETURN,
PLPGSQL_STMT_RETURN_NEXT,
PLPGSQL_STMT_RETURN_QUERY,
PLPGSQL_STMT_RAISE,
PLPGSQL_STMT_EXECSQL,
PLPGSQL_STMT_DYNEXECUTE,
@ -493,6 +494,13 @@ typedef struct
int retvarno;
} PLpgSQL_stmt_return_next;
typedef struct
{ /* RETURN QUERY statement */
int cmd_type;
int lineno;
PLpgSQL_expr *query;
} PLpgSQL_stmt_return_query;
typedef struct
{ /* RAISE statement */
int cmd_type;

7
src/pl/plpgsql/src/scan.l
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.57 2007/04/29 01:21:09 neilc Exp $
* $PostgreSQL: pgsql/src/pl/plpgsql/src/scan.l,v 1.58 2007/07/25 04:19:09 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@ -124,8 +124,8 @@ declare { return K_DECLARE; }
default { return K_DEFAULT; }
diagnostics { return K_DIAGNOSTICS; }
else { return K_ELSE; }
elseif { return K_ELSIF; }
elsif { return K_ELSIF; }
elseif { return K_ELSIF; }
elsif { return K_ELSIF; }
end { return K_END; }
exception { return K_EXCEPTION; }
execute { return K_EXECUTE; }
@ -151,6 +151,7 @@ null { return K_NULL; }
open { return K_OPEN; }
or { return K_OR; }
perform { return K_PERFORM; }
query { return K_QUERY; }
raise { return K_RAISE; }
rename { return K_RENAME; }
result_oid { return K_RESULT_OID; }

49
src/test/regress/expected/plpgsql.out
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@ -3079,3 +3079,52 @@ NOTICE: innerblock.param1 = 2
(1 row)
drop function pl_qual_names(int);
-- tests for RETURN QUERY
create function ret_query1(out int, out int) returns setof record as $$
begin
$1 := -1;
$2 := -2;
return next;
return query select x + 1, x * 10 from generate_series(0, 10) s (x);
return next;
end;
$$ language plpgsql;
select * from ret_query1();
column1 | column2
---------+---------
-1 | -2
1 | 0
2 | 10
3 | 20
4 | 30
5 | 40
6 | 50
7 | 60
8 | 70
9 | 80
10 | 90
11 | 100
-1 | -2
(13 rows)
create type record_type as (x text, y int, z boolean);
create or replace function ret_query2(lim int) returns setof record_type as $$
begin
return query select md5(s.x::text), s.x, s.x > 0
from generate_series(-8, lim) s (x) where s.x % 2 = 0;
end;
$$ language plpgsql;
select * from ret_query2(8);
x | y | z
----------------------------------+----+---
a8d2ec85eaf98407310b72eb73dda247 | -8 | f
596a3d04481816330f07e4f97510c28f | -6 | f
0267aaf632e87a63288a08331f22c7c3 | -4 | f
5d7b9adcbe1c629ec722529dd12e5129 | -2 | f
cfcd208495d565ef66e7dff9f98764da | 0 | f
c81e728d9d4c2f636f067f89cc14862c | 2 | t
a87ff679a2f3e71d9181a67b7542122c | 4 | t
1679091c5a880faf6fb5e6087eb1b2dc | 6 | t
c9f0f895fb98ab9159f51fd0297e236d | 8 | t
(9 rows)

24
src/test/regress/sql/plpgsql.sql
View File

@ -2557,3 +2557,27 @@ $$ language plpgsql;
select pl_qual_names(42);
drop function pl_qual_names(int);
-- tests for RETURN QUERY
create function ret_query1(out int, out int) returns setof record as $$
begin
$1 := -1;
$2 := -2;
return next;
return query select x + 1, x * 10 from generate_series(0, 10) s (x);
return next;
end;
$$ language plpgsql;
select * from ret_query1();
create type record_type as (x text, y int, z boolean);
create or replace function ret_query2(lim int) returns setof record_type as $$
begin
return query select md5(s.x::text), s.x, s.x > 0
from generate_series(-8, lim) s (x) where s.x % 2 = 0;
end;
$$ language plpgsql;
select * from ret_query2(8);