Add command to show tablespaces attached to a hypertable

Users can now call `show_tablespaces()` to list the tablespaces
attached to a particular hypertable.

Author: erimatnor

sql/ddl_api.sql

@@ -317,3 +317,9 @@ CREATE OR REPLACE FUNCTION detach_tablespaces(hypertable REGCLASS)
 $BODY$
     SELECT * FROM _timescaledb_internal.detach_tablespaces(hypertable);
 $BODY$;
+
+CREATE OR REPLACE FUNCTION show_tablespaces(hypertable REGCLASS)
+       RETURNS SETOF NAME LANGUAGE SQL AS
+$BODY$
+    SELECT * FROM _timescaledb_internal.show_tablespaces(hypertable);
+$BODY$;

sql/ddl_internal.sql

@@ -627,6 +627,9 @@ AS '$libdir/timescaledb', 'tablespace_detach' LANGUAGE C VOLATILE;
 CREATE OR REPLACE FUNCTION _timescaledb_internal.detach_tablespaces(hypertable REGCLASS) RETURNS INTEGER
 AS '$libdir/timescaledb', 'tablespace_detach_all_from_hypertable' LANGUAGE C VOLATILE;
 
+CREATE OR REPLACE FUNCTION _timescaledb_internal.show_tablespaces(hypertable REGCLASS) RETURNS SETOF NAME
+AS '$libdir/timescaledb', 'tablespace_show' LANGUAGE C VOLATILE STRICT;
+
 --documentation of these function located in chunk_index.h
 CREATE OR REPLACE FUNCTION _timescaledb_internal.chunk_index_clone(chunk_index_oid OID) RETURNS OID
 AS '$libdir/timescaledb', 'chunk_index_clone' LANGUAGE C VOLATILE STRICT;

src/tablespace.c

@@ -8,6 +8,7 @@
 #include <commands/tablespace.h>
 #include <access/xact.h>
 #include <miscadmin.h>
+#include <funcapi.h>
 
 #include "hypertable_cache.h"
 #include "errors.h"
@@ -469,3 +470,51 @@ tablespace_detach_all_from_hypertable(PG_FUNCTION_ARGS)
 
 	PG_RETURN_INT32(tablespace_detach_all(PG_GETARG_OID(0)));
 }
+
+TS_FUNCTION_INFO_V1(tablespace_show);
+
+Datum
+tablespace_show(PG_FUNCTION_ARGS)
+{
+	FuncCallContext *funcctx;
+	Oid			hypertable_oid = PG_ARGISNULL(0) ? InvalidOid : PG_GETARG_OID(0);
+	Cache	   *hcache;
+	Hypertable *ht;
+
+	if (SRF_IS_FIRSTCALL())
+	{
+		MemoryContext oldcontext;
+
+		if (!OidIsValid(hypertable_oid))
+			elog(ERROR, "Invalid argument");
+
+		funcctx = SRF_FIRSTCALL_INIT();
+		oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
+		funcctx->user_fctx = hypertable_cache_pin();
+		MemoryContextSwitchTo(oldcontext);
+	}
+
+	funcctx = SRF_PERCALL_SETUP();
+	hcache = funcctx->user_fctx;
+	ht = hypertable_cache_get_entry(hcache, hypertable_oid);
+
+	if (NULL == ht)
+		ereport(ERROR,
+				(errcode(ERRCODE_IO_HYPERTABLE_NOT_EXIST),
+				 errmsg("Table \"%s\" is not a hypertable",
+						get_rel_name(hypertable_oid))));
+
+	if (NULL != ht->tablespaces && funcctx->call_cntr < (uint64) ht->tablespaces->num_tablespaces)
+	{
+		Tablespaces *tspcs = ht->tablespaces;
+		Oid			tablespace_oid = tspcs->tablespaces[funcctx->call_cntr].tablespace_oid;
+		const char *tablespace_name = get_tablespace_name(tablespace_oid);
+
+		SRF_RETURN_NEXT(funcctx, CStringGetDatum(tablespace_name));
+	}
+	else
+	{
+		cache_release(hcache);
+		SRF_RETURN_DONE(funcctx);
+	}
+}

test/expected/extension.out

@@ -27,6 +27,7 @@ ORDER BY proname;
  indexes_relation_size_pretty
  last
  set_chunk_time_interval
+ show_tablespaces
  time_bucket
-(17 rows)
+(18 rows)
 

test/expected/pg_dump.out

@@ -49,7 +49,7 @@ SELECT count(*)
      AND refobjid = (SELECT oid FROM pg_extension WHERE extname = 'timescaledb');
  count 
 -------
-   123
+   125
 (1 row)
 
 SELECT * FROM test.show_columns('public."two_Partitions"');
@@ -235,7 +235,7 @@ SELECT count(*)
      AND refobjid = (SELECT oid FROM pg_extension WHERE extname = 'timescaledb');
  count 
 -------
-   123
+   125
 (1 row)
 
 --main table and chunk schemas should be the same

test/expected/tablespace.out

@@ -68,6 +68,13 @@ SELECT * FROM _timescaledb_catalog.tablespace;
   2 |             1 | tablespace2
 (2 rows)
 
+SELECT * FROM show_tablespaces('tspace_2dim');
+ show_tablespaces 
+------------------
+ tablespace1
+ tablespace2
+(2 rows)
+
 --insert into another chunk
 INSERT INTO tspace_2dim VALUES ('2017-01-20T09:00:01', 24.3, 'brown');
 SELECT relname, spcname FROM pg_class c
@@ -141,6 +148,19 @@ SELECT * FROM _timescaledb_catalog.tablespace;
   4 |             2 | tablespace2
 (3 rows)
 
+SELECT * FROM show_tablespaces('tspace_1dim');
+ show_tablespaces 
+------------------
+ tablespace2
+(1 row)
+
+SELECT * FROM show_tablespaces('tspace_2dim');
+ show_tablespaces 
+------------------
+ tablespace1
+ tablespace2
+(2 rows)
+
 --detach the other tablespace
 SELECT detach_tablespace('tablespace2', 'tspace_1dim');
  detach_tablespace 
@@ -155,6 +175,18 @@ SELECT * FROM _timescaledb_catalog.tablespace;
   2 |             1 | tablespace2
 (2 rows)
 
+SELECT * FROM show_tablespaces('tspace_1dim');
+ show_tablespaces 
+------------------
+(0 rows)
+
+SELECT * FROM show_tablespaces('tspace_2dim');
+ show_tablespaces 
+------------------
+ tablespace1
+ tablespace2
+(2 rows)
+
 --detaching a tablespace from table without permissions should fail
 SELECT detach_tablespace('tablespace2', 'tspace_2dim');
 ERROR:  User "default_perm_user_2" lacks permissions on table "tspace_2dim"
@@ -173,6 +205,16 @@ SELECT * FROM _timescaledb_catalog.tablespace;
 ----+---------------+-----------------
 (0 rows)
 
+SELECT * FROM show_tablespaces('tspace_1dim');
+ show_tablespaces 
+------------------
+(0 rows)
+
+SELECT * FROM show_tablespaces('tspace_2dim');
+ show_tablespaces 
+------------------
+(0 rows)
+
 --cleanup
 DROP TABLE tspace_1dim CASCADE;
 DROP TABLE tspace_2dim CASCADE;

test/sql/tablespace.sql

@@ -52,6 +52,7 @@ GRANT :ROLE_DEFAULT_PERM_USER_2 TO :ROLE_DEFAULT_PERM_USER;
 SELECT attach_tablespace('tablespace2', 'tspace_2dim');
 
 SELECT * FROM _timescaledb_catalog.tablespace;
+SELECT * FROM show_tablespaces('tspace_2dim');
 
 --insert into another chunk
 INSERT INTO tspace_2dim VALUES ('2017-01-20T09:00:01', 24.3, 'brown');
@@ -87,10 +88,14 @@ INNER JOIN _timescaledb_catalog.chunk ch ON (ch.table_name = c.relname);
 --should only detach from 'tspace_1dim' (1 tablespace)
 SELECT detach_tablespace('tablespace1');
 SELECT * FROM _timescaledb_catalog.tablespace;
+SELECT * FROM show_tablespaces('tspace_1dim');
+SELECT * FROM show_tablespaces('tspace_2dim');
 
 --detach the other tablespace
 SELECT detach_tablespace('tablespace2', 'tspace_1dim');
 SELECT * FROM _timescaledb_catalog.tablespace;
+SELECT * FROM show_tablespaces('tspace_1dim');
+SELECT * FROM show_tablespaces('tspace_2dim');
 
 --detaching a tablespace from table without permissions should fail
 SELECT detach_tablespace('tablespace2', 'tspace_2dim');
@@ -100,6 +105,8 @@ SELECT detach_tablespaces('tspace_2dim');
 SET ROLE :ROLE_DEFAULT_PERM_USER;
 SELECT detach_tablespaces('tspace_2dim');
 SELECT * FROM _timescaledb_catalog.tablespace;
+SELECT * FROM show_tablespaces('tspace_1dim');
+SELECT * FROM show_tablespaces('tspace_2dim');
 
 --cleanup
 DROP TABLE tspace_1dim CASCADE;