Remove empty chunks on TRUNCATE hypertable.

sql/ddl_internal.sql

@@ -480,3 +480,28 @@ CREATE OR REPLACE FUNCTION _timescaledb_internal.timescale_trigger_names()
 $BODY$
    SELECT array['_timescaledb_main_insert_trigger', '_timescaledb_main_after_insert_trigger'];
 $BODY$;
+
+
+CREATE OR REPLACE FUNCTION _timescaledb_internal.truncate_hypertable(
+    schema_name     NAME,
+    table_name      NAME
+)
+    RETURNS VOID
+    LANGUAGE PLPGSQL VOLATILE
+    SECURITY DEFINER SET search_path = ''
+    AS
+$BODY$
+DECLARE
+    hypertable_row _timescaledb_catalog.hypertable;
+BEGIN
+
+    SELECT * INTO STRICT hypertable_row
+    FROM _timescaledb_catalog.hypertable ht
+    WHERE ht.schema_name = truncate_hypertable.schema_name
+    AND ht.table_name = truncate_hypertable.table_name;
+
+    DELETE FROM _timescaledb_catalog.chunk
+    WHERE hypertable_id = hypertable_row.id;
+
+END
+$BODY$;

src/metadata_queries.c

@@ -49,16 +49,23 @@ prepare_plan(const char *src, int nargs, Oid *argtypes)
 #define CHUNK_CREATE_ARGS (Oid[]) {INT4ARRAYOID, INT8ARRAYOID}
 #define CHUNK_CREATE "SELECT * FROM _timescaledb_internal.chunk_create($1, $2)"
 
+/* plan for creating a chunk via create_chunk(). */
+DEFINE_PLAN(create_chunk_plan, CHUNK_CREATE, 2, CHUNK_CREATE_ARGS)
+
 /* old_schema, old_name, new_schema, new_name */
 #define RENAME_HYPERTABLE_ARGS (Oid[]) {NAMEOID, NAMEOID, TEXTOID, TEXTOID}
 #define RENAME_HYPERTABLE "SELECT * FROM _timescaledb_internal.rename_hypertable($1, $2, $3, $4)"
 
-/* plan for creating a chunk via create_chunk(). */
-DEFINE_PLAN(create_chunk_plan, CHUNK_CREATE, 2, CHUNK_CREATE_ARGS)
-
 /* plan to rename hypertable */
 DEFINE_PLAN(rename_hypertable_plan, RENAME_HYPERTABLE, 4, RENAME_HYPERTABLE_ARGS)
 
+/* schema, name */
+#define TRUNCATE_HYPERTABLE_ARGS (Oid[]) {NAMEOID, NAMEOID}
+#define TRUNCATE_HYPERTABLE "SELECT * FROM _timescaledb_internal.truncate_hypertable($1, $2)"
+
+/* plan to truncate hypertable */
+DEFINE_PLAN(truncate_hypertable_plan, TRUNCATE_HYPERTABLE, 2, TRUNCATE_HYPERTABLE_ARGS)
+
 static HeapTuple
 chunk_tuple_create_spi_connected(Hyperspace *hs, Point *p, SPIPlanPtr plan)
 {
@@ -158,3 +165,35 @@ spi_hypertable_rename(Hypertable *ht, char *new_schema_name, char *new_table_nam
 
 	return;
 }
+
+static void
+hypertable_truncate_spi_connected(Hypertable *ht, SPIPlanPtr plan)
+{
+	int			ret;
+	Datum		args[2];
+
+	args[0] = PointerGetDatum(NameStr(ht->fd.schema_name));
+	args[1] = PointerGetDatum(NameStr(ht->fd.table_name));
+
+	ret = SPI_execute_plan(plan, args, NULL, false, 2);
+
+	if (ret <= 0)
+		elog(ERROR, "Got an SPI error %d", ret);
+
+	return;
+}
+
+void
+spi_hypertable_truncate(Hypertable *ht)
+{
+	SPIPlanPtr	plan = truncate_hypertable_plan();
+
+	if (SPI_connect() < 0)
+		elog(ERROR, "Got an SPI connect error");
+
+	hypertable_truncate_spi_connected(ht, plan);
+
+	SPI_finish();
+
+	return;
+}

src/metadata_queries.h

@@ -10,5 +10,6 @@ typedef struct Hypertable Hypertable;
 
 extern Chunk *spi_chunk_create(Hyperspace *hs, Point *p);
 extern void spi_hypertable_rename(Hypertable *ht, char *new_schema_name, char *new_table_name);
+extern void spi_hypertable_truncate(Hypertable *ht);
 
 #endif   /* TIMESCALEDB_METADATA_QUERIES_H */

src/process_utility.c

@@ -52,6 +52,33 @@ timescaledb_ProcessUtility(Node *parsetree,
 		return;
 	}
 
+	/* Truncate a hypertable */
+	if (IsA(parsetree, TruncateStmt)) {
+		TruncateStmt *truncatestmt = (TruncateStmt *) parsetree;
+		ListCell   *cell;
+
+		foreach(cell, truncatestmt->relations)
+		{
+			Oid			relId = RangeVarGetRelid(lfirst(cell), NoLock, true);
+
+			if (OidIsValid(relId))
+			{
+				Cache	   *hcache = hypertable_cache_pin();
+				Hypertable *hentry = hypertable_cache_get_entry(hcache, relId);
+
+				if (hentry != NULL) {
+					executor_level_enter();
+					spi_hypertable_truncate(hentry);
+					executor_level_exit();
+				}
+				cache_release(hcache);
+			}
+
+		}
+
+		prev_ProcessUtility((Node *) truncatestmt, query_string, context, params, dest, completion_tag);
+		return;
+	}
 
 	/* Change the schema of hypertable */
 	if (IsA(parsetree, AlterObjectSchemaStmt))

test/expected/pg_dump.out

@@ -42,7 +42,7 @@ SELECT count(*)
      AND refobjid = (SELECT oid FROM pg_extension WHERE extname = 'timescaledb');
  count 
 -------
-   126
+   127
 (1 row)
 
 \c postgres
@@ -66,7 +66,7 @@ SELECT count(*)
      AND refobjid = (SELECT oid FROM pg_extension WHERE extname = 'timescaledb');
  count 
 -------
-   126
+   127
 (1 row)
 
 \c single

test/expected/truncate_hypertable.out

@@ -0,0 +1,129 @@
+\o /dev/null
+\ir include/insert_two_partitions.sql
+\ir create_single_db.sql
+SET client_min_messages = WARNING;
+DROP DATABASE IF EXISTS single;
+SET client_min_messages = NOTICE;
+CREATE DATABASE single;
+\c single
+CREATE EXTENSION IF NOT EXISTS timescaledb;
+\c single
+CREATE TABLE PUBLIC."two_Partitions" (
+  "timeCustom" BIGINT NOT NULL,
+  device_id TEXT NOT NULL,
+  series_0 DOUBLE PRECISION NULL,
+  series_1 DOUBLE PRECISION NULL,
+  series_2 DOUBLE PRECISION NULL,
+  series_bool BOOLEAN NULL
+);
+CREATE INDEX ON PUBLIC."two_Partitions" (device_id, "timeCustom" DESC NULLS LAST) WHERE device_id IS NOT NULL;
+CREATE INDEX ON PUBLIC."two_Partitions" ("timeCustom" DESC NULLS LAST, series_0) WHERE series_0 IS NOT NULL;
+CREATE INDEX ON PUBLIC."two_Partitions" ("timeCustom" DESC NULLS LAST, series_1)  WHERE series_1 IS NOT NULL;
+CREATE INDEX ON PUBLIC."two_Partitions" ("timeCustom" DESC NULLS LAST, series_2) WHERE series_2 IS NOT NULL;
+CREATE INDEX ON PUBLIC."two_Partitions" ("timeCustom" DESC NULLS LAST, series_bool) WHERE series_bool IS NOT NULL;
+CREATE INDEX ON PUBLIC."two_Partitions" ("timeCustom" DESC NULLS LAST, device_id);
+SELECT * FROM create_hypertable('"public"."two_Partitions"'::regclass, 'timeCustom'::name, 'device_id'::name, associated_schema_name=>'_timescaledb_internal'::text, number_partitions => 2);
+\set QUIET off
+BEGIN;
+\COPY public."two_Partitions" FROM 'data/ds1_dev1_1.tsv' NULL AS '';
+COMMIT;
+INSERT INTO public."two_Partitions"("timeCustom", device_id, series_0, series_1) VALUES
+(1257987600000000000, 'dev1', 1.5, 1),
+(1257987600000000000, 'dev1', 1.5, 2),
+(1257894000000000000, 'dev2', 1.5, 1),
+(1257894002000000000, 'dev1', 2.5, 3);
+INSERT INTO "two_Partitions"("timeCustom", device_id, series_0, series_1) VALUES
+(1257894000000000000, 'dev2', 1.5, 2);
+\set QUIET on
+\o
+SELECT * FROM _timescaledb_catalog.hypertable;
+ id | schema_name |   table_name   | associated_schema_name | associated_table_prefix | num_dimensions 
+----+-------------+----------------+------------------------+-------------------------+----------------
+  1 | public      | two_Partitions | _timescaledb_internal  | _hyper_1                |              2
+(1 row)
+
+SELECT * FROM _timescaledb_catalog.chunk;
+ id | hypertable_id |      schema_name      |    table_name    
+----+---------------+-----------------------+------------------
+  1 |             1 | _timescaledb_internal | _hyper_1_1_chunk
+  2 |             1 | _timescaledb_internal | _hyper_1_2_chunk
+  3 |             1 | _timescaledb_internal | _hyper_1_3_chunk
+  4 |             1 | _timescaledb_internal | _hyper_1_4_chunk
+(4 rows)
+
+\dt "_timescaledb_internal".*
+                      List of relations
+        Schema         |       Name       | Type  |  Owner   
+-----------------------+------------------+-------+----------
+ _timescaledb_internal | _hyper_1_1_chunk | table | postgres
+ _timescaledb_internal | _hyper_1_2_chunk | table | postgres
+ _timescaledb_internal | _hyper_1_3_chunk | table | postgres
+ _timescaledb_internal | _hyper_1_4_chunk | table | postgres
+(4 rows)
+
+SELECT * FROM "two_Partitions";
+     timeCustom      | device_id | series_0 | series_1 | series_2 | series_bool 
+---------------------+-----------+----------+----------+----------+-------------
+ 1257894000000000000 | dev1      |      1.5 |        1 |        2 | t
+ 1257894000000000000 | dev1      |      1.5 |        2 |          | 
+ 1257894000000001000 | dev1      |      2.5 |        3 |          | 
+ 1257894001000000000 | dev1      |      3.5 |        4 |          | 
+ 1257894002000000000 | dev1      |      5.5 |        6 |          | t
+ 1257894002000000000 | dev1      |      5.5 |        7 |          | f
+ 1257894002000000000 | dev1      |      2.5 |        3 |          | 
+ 1257897600000000000 | dev1      |      4.5 |        5 |          | f
+ 1257987600000000000 | dev1      |      1.5 |        1 |          | 
+ 1257987600000000000 | dev1      |      1.5 |        2 |          | 
+ 1257894000000000000 | dev2      |      1.5 |        1 |          | 
+ 1257894000000000000 | dev2      |      1.5 |        2 |          | 
+(12 rows)
+
+SET client_min_messages = WARNING;
+TRUNCATE "two_Partitions";
+SELECT * FROM _timescaledb_catalog.hypertable;
+ id | schema_name |   table_name   | associated_schema_name | associated_table_prefix | num_dimensions 
+----+-------------+----------------+------------------------+-------------------------+----------------
+  1 | public      | two_Partitions | _timescaledb_internal  | _hyper_1                |              2
+(1 row)
+
+SELECT * FROM _timescaledb_catalog.chunk;
+ id | hypertable_id | schema_name | table_name 
+----+---------------+-------------+------------
+(0 rows)
+
+-- should be empty
+\set ON_ERROR_STOP 0
+\dt "_timescaledb_internal".*
+      List of relations
+ Schema | Name | Type | Owner 
+--------+------+------+-------
+(0 rows)
+
+\set ON_ERROR_STOP 1
+\d+ "two_Partitions"
+                           Table "public.two_Partitions"
+   Column    |       Type       | Modifiers | Storage  | Stats target | Description 
+-------------+------------------+-----------+----------+--------------+-------------
+ timeCustom  | bigint           | not null  | plain    |              | 
+ device_id   | text             | not null  | extended |              | 
+ series_0    | double precision |           | plain    |              | 
+ series_1    | double precision |           | plain    |              | 
+ series_2    | double precision |           | plain    |              | 
+ series_bool | boolean          |           | plain    |              | 
+Indexes:
+    "two_Partitions_device_id_timeCustom_idx" btree (device_id, "timeCustom" DESC NULLS LAST) WHERE device_id IS NOT NULL
+    "two_Partitions_timeCustom_device_id_idx" btree ("timeCustom" DESC NULLS LAST, device_id)
+    "two_Partitions_timeCustom_idx" btree ("timeCustom" DESC)
+    "two_Partitions_timeCustom_series_0_idx" btree ("timeCustom" DESC NULLS LAST, series_0) WHERE series_0 IS NOT NULL
+    "two_Partitions_timeCustom_series_1_idx" btree ("timeCustom" DESC NULLS LAST, series_1) WHERE series_1 IS NOT NULL
+    "two_Partitions_timeCustom_series_2_idx" btree ("timeCustom" DESC NULLS LAST, series_2) WHERE series_2 IS NOT NULL
+    "two_Partitions_timeCustom_series_bool_idx" btree ("timeCustom" DESC NULLS LAST, series_bool) WHERE series_bool IS NOT NULL
+Triggers:
+    _timescaledb_main_after_insert_trigger AFTER INSERT ON "two_Partitions" FOR EACH STATEMENT EXECUTE PROCEDURE _timescaledb_internal.main_table_after_insert_trigger()
+    _timescaledb_main_insert_trigger BEFORE INSERT ON "two_Partitions" FOR EACH ROW EXECUTE PROCEDURE _timescaledb_internal.main_table_insert_trigger()
+
+SELECT * FROM "two_Partitions";
+ timeCustom | device_id | series_0 | series_1 | series_2 | series_bool 
+------------+-----------+----------+----------+----------+-------------
+(0 rows)
+

test/sql/truncate_hypertable.sql

@@ -0,0 +1,24 @@
+\o /dev/null
+\ir include/insert_two_partitions.sql
+\o
+
+SELECT * FROM _timescaledb_catalog.hypertable;
+SELECT * FROM _timescaledb_catalog.chunk;
+\dt "_timescaledb_internal".*
+SELECT * FROM "two_Partitions";
+
+SET client_min_messages = WARNING;
+TRUNCATE "two_Partitions";
+
+SELECT * FROM _timescaledb_catalog.hypertable;
+SELECT * FROM _timescaledb_catalog.chunk;
+
+-- should be empty
+\set ON_ERROR_STOP 0
+\dt "_timescaledb_internal".*
+\set ON_ERROR_STOP 1
+
+\d+ "two_Partitions"
+SELECT * FROM "two_Partitions";
+
+