Add table mappings to compression settings

Refactor the compression settings metadata table to include a mapping
from a chunk's relid to its compressed chunk's relid.

This simplifies the code that looks up compression metadata as it no
longer requires first looking up the corresponding compressed chunk in
the "chunk" metadata table. Instead, given the non-compressed chunk's
relid, the corresponding compressed chunk's relid can easily be looked
up via the compression settings.

The refactoring is a step towards removing a chunk's compression table
from the chunk metadata. In other words, the "compressed chunk" will
no longer be a chunk, just a relation associated with the regular
chunk via compression settings. However, this requires further
refactoring that is left for follow-up changes.

sql/pre_install/tables.sql

@@ -471,7 +471,8 @@ CREATE TABLE _timescaledb_catalog.compression_algorithm (
 );
 
 CREATE TABLE _timescaledb_catalog.compression_settings (
-	relid regclass NOT NULL,
+  relid regclass NOT NULL,
+  compress_relid regclass NULL,
   segmentby text[],
   orderby text[],
   orderby_desc bool[],
@@ -483,6 +484,7 @@ CREATE TABLE _timescaledb_catalog.compression_settings (
 );
 
 SELECT pg_catalog.pg_extension_config_dump('_timescaledb_catalog.compression_settings', '');
+CREATE INDEX compression_settings_compress_relid_idx ON _timescaledb_catalog.compression_settings (compress_relid);
 
 CREATE TABLE _timescaledb_catalog.compression_chunk_size (
   chunk_id integer NOT NULL,

sql/updates/latest-dev.sql

@@ -1 +1,55 @@
+-------------------------------
+-- Update compression settings
+-------------------------------
+CREATE TABLE _timescaledb_catalog.tempsettings (LIKE _timescaledb_catalog.compression_settings);
+INSERT INTO _timescaledb_catalog.tempsettings SELECT * FROM _timescaledb_catalog.compression_settings;
+ALTER EXTENSION timescaledb DROP TABLE _timescaledb_catalog.compression_settings;
+DROP TABLE _timescaledb_catalog.compression_settings CASCADE;
 
+CREATE TABLE _timescaledb_catalog.compression_settings (
+  relid regclass NOT NULL,
+  compress_relid regclass NULL,
+  segmentby text[],
+  orderby text[],
+  orderby_desc bool[],
+  orderby_nullsfirst bool[],
+  CONSTRAINT compression_settings_pkey PRIMARY KEY (relid),
+  CONSTRAINT compression_settings_check_segmentby CHECK (array_ndims(segmentby) = 1),
+  CONSTRAINT compression_settings_check_orderby_null CHECK ((orderby IS NULL AND orderby_desc IS NULL AND orderby_nullsfirst IS NULL) OR (orderby IS NOT NULL AND orderby_desc IS NOT NULL AND orderby_nullsfirst IS NOT NULL)),
+  CONSTRAINT compression_settings_check_orderby_cardinality CHECK (array_ndims(orderby) = 1 AND array_ndims(orderby_desc) = 1 AND array_ndims(orderby_nullsfirst) = 1 AND cardinality(orderby) = cardinality(orderby_desc) AND cardinality(orderby) = cardinality(orderby_nullsfirst))
+);
+
+-- Insert updated settings
+INSERT INTO _timescaledb_catalog.compression_settings
+SELECT
+    CASE
+        WHEN h.schema_name IS NOT NULL THEN
+            cs.relid
+        WHEN cch.table_name IS NOT NULL THEN
+            format('%I.%I', ch.schema_name, ch.table_name)::regclass
+    END AS relid,
+    CASE
+        WHEN h.schema_name IS NOT NULL THEN
+            NULL
+        ELSE
+            cs.relid
+    END AS compress_relid,
+    cs.segmentby,
+    cs.orderby,
+    cs.orderby_desc,
+    cs.orderby_nullsfirst
+FROM
+    _timescaledb_catalog.tempsettings cs
+LEFT JOIN
+    _timescaledb_catalog.hypertable h ON (cs.relid = format('%I.%I', h.schema_name, h.table_name)::regclass)
+LEFT JOIN
+    _timescaledb_catalog.chunk cch ON (cs.relid = format('%I.%I', cch.schema_name, cch.table_name)::regclass)
+LEFT JOIN
+    _timescaledb_catalog.chunk ch ON (cch.id = ch.compressed_chunk_id);
+
+-- Add index on secondary compressed relid key
+CREATE INDEX compression_settings_compress_relid_idx ON _timescaledb_catalog.compression_settings (compress_relid);
+
+DROP TABLE _timescaledb_catalog.tempsettings CASCADE;
+GRANT SELECT ON _timescaledb_catalog.compression_settings TO PUBLIC;
+SELECT pg_catalog.pg_extension_config_dump('_timescaledb_catalog.compression_settings', '');

sql/updates/reverse-dev.sql

@@ -0,0 +1,37 @@
+-- Update compression settings
+CREATE TABLE _timescaledb_catalog.tempsettings (LIKE _timescaledb_catalog.compression_settings);
+INSERT INTO _timescaledb_catalog.tempsettings SELECT * FROM _timescaledb_catalog.compression_settings;
+ALTER EXTENSION timescaledb DROP TABLE _timescaledb_catalog.compression_settings;
+DROP TABLE _timescaledb_catalog.compression_settings CASCADE;
+
+CREATE TABLE _timescaledb_catalog.compression_settings (
+  relid regclass NOT NULL,
+  segmentby text[],
+  orderby text[],
+  orderby_desc bool[],
+  orderby_nullsfirst bool[],
+  CONSTRAINT compression_settings_pkey PRIMARY KEY (relid),
+  CONSTRAINT compression_settings_check_segmentby CHECK (array_ndims(segmentby) = 1),
+  CONSTRAINT compression_settings_check_orderby_null CHECK ((orderby IS NULL AND orderby_desc IS NULL AND orderby_nullsfirst IS NULL) OR (orderby IS NOT NULL AND orderby_desc IS NOT NULL AND orderby_nullsfirst IS NOT NULL)),
+  CONSTRAINT compression_settings_check_orderby_cardinality CHECK (array_ndims(orderby) = 1 AND array_ndims(orderby_desc) = 1 AND array_ndims(orderby_nullsfirst) = 1 AND cardinality(orderby) = cardinality(orderby_desc) AND cardinality(orderby) = cardinality(orderby_nullsfirst))
+);
+
+-- Revert information in compression settings
+INSERT INTO _timescaledb_catalog.compression_settings
+SELECT
+    CASE
+        WHEN cs.compress_relid IS NULL THEN
+            cs.relid
+        ELSE
+            cs.compress_relid
+    END as relid,
+	cs.segmentby,
+	cs.orderby,
+	cs.orderby_desc,
+	cs.orderby_nullsfirst
+FROM
+	_timescaledb_catalog.tempsettings cs;
+
+DROP TABLE _timescaledb_catalog.tempsettings CASCADE;
+GRANT SELECT ON _timescaledb_catalog.compression_settings TO PUBLIC;
+SELECT pg_catalog.pg_extension_config_dump('_timescaledb_catalog.compression_settings', '');

sql/views.sql

@@ -390,8 +390,7 @@ CREATE OR REPLACE VIEW timescaledb_information.chunk_compression_settings AS
 		un.orderby
 	FROM _timescaledb_catalog.hypertable ht
 	INNER JOIN _timescaledb_catalog.chunk ch ON ch.hypertable_id = ht.id
-  INNER JOIN _timescaledb_catalog.chunk ch2 ON ch2.id = ch.compressed_chunk_id
-  LEFT JOIN _timescaledb_catalog.compression_settings s ON format('%I.%I',ch2.schema_name,ch2.table_name)::regclass = s.relid
+ 	INNER JOIN _timescaledb_catalog.compression_settings s ON (format('%I.%I',ch.schema_name,ch.table_name)::regclass = s.relid AND format('%I.%I',ch.schema_name,ch.table_name)::regclass != s.compress_relid)
 	LEFT JOIN LATERAL (
 		SELECT
 			string_agg(

src/chunk.c

@@ -10,6 +10,7 @@
 #include <access/reloptions.h>
 #include <access/tupdesc.h>
 #include <access/xact.h>
+#include <c.h>
 #include <catalog/indexing.h>
 #include <catalog/namespace.h>
 #include <catalog/pg_class.h>
@@ -2807,6 +2808,10 @@ typedef enum ChunkDeleteResult
 } ChunkDeleteResult;
 
 /* Delete the chunk tuple.
+ *
+ * relid: Required when deleting via an event trigger hook, because at that
+ * point the relation is gone and it is no longer possible to resolve the Oid
+ * from the PG catalog.
  *
  * preserve_chunk_catalog_row - instead of deleting the row, mark it as dropped.
  * this is used when we need to preserve catalog information about the chunk
@@ -2824,7 +2829,7 @@ typedef enum ChunkDeleteResult
  * of tuples to process.
  */
 static ChunkDeleteResult
-chunk_tuple_delete(TupleInfo *ti, DropBehavior behavior, bool preserve_chunk_catalog_row)
+chunk_tuple_delete(TupleInfo *ti, Oid relid, DropBehavior behavior, bool preserve_chunk_catalog_row)
 {
 	FormData_chunk form;
 	CatalogSecurityContext sec_ctx;
@@ -2910,19 +2915,39 @@ chunk_tuple_delete(TupleInfo *ti, DropBehavior behavior, bool preserve_chunk_cat
 	/* Delete any rows in _timescaledb_catalog.chunk_column_stats corresponding to this chunk */
 	ts_chunk_column_stats_delete_by_chunk_id(form.id);
 
+	if (!OidIsValid(relid))
+	{
+		/*
+		 * If the chunk is deleted as a result of deleting the Hypertable, and
+		 * it is cleaned up in the DROP eventtrigger hook, it might not be
+		 * possible to resolve the relid because the relation is already gone
+		 * in pg_catalog. But that's OK, because compression settings will be
+		 * cleaned up when processing the eventtrigger.
+		 */
+		relid = ts_get_relation_relid(NameStr(form.schema_name), NameStr(form.table_name), true);
+	}
+
 	if (form.compressed_chunk_id != INVALID_CHUNK_ID)
 	{
 		Chunk *compressed_chunk = ts_chunk_get_by_id(form.compressed_chunk_id, false);
 
-		/* The chunk may have been delete by a CASCADE */
+		if (OidIsValid(relid))
+			ts_compression_settings_delete(relid);
+
+		/* The chunk may have been deleted by a CASCADE */
 		if (compressed_chunk != NULL)
 		{
 			/* Plain drop without preserving catalog row because this is the compressed
 			 * chunk */
-			ts_compression_settings_delete(compressed_chunk->table_id);
 			ts_chunk_drop(compressed_chunk, behavior, DEBUG1);
 		}
 	}
+	else if (OidIsValid(relid))
+	{
+		/* If there is no compressed chunk ID, this might be the actual
+		 * compressed chunk */
+		ts_compression_settings_delete_by_compress_relid(relid);
+	}
 
 	ts_catalog_database_info_become_owner(ts_catalog_database_info_get(), &sec_ctx);
 
@@ -2973,7 +2998,8 @@ init_scan_by_qualified_table_name(ScanIterator *iterator, const char *schema_nam
 }
 
 static int
-chunk_delete(ScanIterator *iterator, DropBehavior behavior, bool preserve_chunk_catalog_row)
+chunk_delete(ScanIterator *iterator, Oid relid, DropBehavior behavior,
+			 bool preserve_chunk_catalog_row)
 {
 	int count = 0;
 
@@ -2982,6 +3008,7 @@ chunk_delete(ScanIterator *iterator, DropBehavior behavior, bool preserve_chunk_
 		ChunkDeleteResult res;
 
 		res = chunk_tuple_delete(ts_scan_iterator_tuple_info(iterator),
+								 relid,
 								 behavior,
 								 preserve_chunk_catalog_row);
 
@@ -3001,14 +3028,14 @@ chunk_delete(ScanIterator *iterator, DropBehavior behavior, bool preserve_chunk_
 }
 
 static int
-ts_chunk_delete_by_name_internal(const char *schema, const char *table, DropBehavior behavior,
-								 bool preserve_chunk_catalog_row)
+ts_chunk_delete_by_name_internal(const char *schema, const char *table, Oid relid,
+								 DropBehavior behavior, bool preserve_chunk_catalog_row)
 {
 	ScanIterator iterator = ts_scan_iterator_create(CHUNK, RowExclusiveLock, CurrentMemoryContext);
 	int count;
 
 	init_scan_by_qualified_table_name(&iterator, schema, table);
-	count = chunk_delete(&iterator, behavior, preserve_chunk_catalog_row);
+	count = chunk_delete(&iterator, relid, behavior, preserve_chunk_catalog_row);
 
 	/* (schema,table) names and (hypertable_id) are unique so should only have
 	 * dropped one chunk or none (if not found) */
@@ -3020,17 +3047,20 @@ ts_chunk_delete_by_name_internal(const char *schema, const char *table, DropBeha
 int
 ts_chunk_delete_by_name(const char *schema, const char *table, DropBehavior behavior)
 {
-	return ts_chunk_delete_by_name_internal(schema, table, behavior, false);
+	Oid relid = ts_get_relation_relid(schema, table, false);
+	return ts_chunk_delete_by_name_internal(schema, table, relid, behavior, false);
 }
 
-static int
-ts_chunk_delete_by_relid(Oid relid, DropBehavior behavior, bool preserve_chunk_catalog_row)
+int
+ts_chunk_delete_by_relid_and_relname(Oid relid, const char *schemaname, const char *tablename,
+									 DropBehavior behavior, bool preserve_chunk_catalog_row)
 {
 	if (!OidIsValid(relid))
 		return 0;
 
-	return ts_chunk_delete_by_name_internal(get_namespace_name(get_rel_namespace(relid)),
-											get_rel_name(relid),
+	return ts_chunk_delete_by_name_internal(schemaname,
+											tablename,
+											relid,
 											behavior,
 											preserve_chunk_catalog_row);
 }
@@ -3053,7 +3083,7 @@ ts_chunk_delete_by_hypertable_id(int32 hypertable_id)
 
 	init_scan_by_hypertable_id(&iterator, hypertable_id);
 
-	return chunk_delete(&iterator, DROP_RESTRICT, false);
+	return chunk_delete(&iterator, InvalidOid, DROP_RESTRICT, false);
 }
 
 bool
@@ -3738,7 +3768,11 @@ ts_chunk_drop_internal(const Chunk *chunk, DropBehavior behavior, int32 log_leve
 			 NameStr(chunk->fd.table_name));
 
 	/* Remove the chunk from the chunk table */
-	ts_chunk_delete_by_relid(chunk->table_id, behavior, preserve_catalog_row);
+	ts_chunk_delete_by_relid_and_relname(chunk->table_id,
+										 NameStr(chunk->fd.schema_name),
+										 NameStr(chunk->fd.table_name),
+										 behavior,
+										 preserve_catalog_row);
 
 	/* Drop the table */
 	performDeletion(&objaddr, behavior, 0);

src/chunk.h

@@ -190,6 +190,9 @@ extern void ts_chunk_recreate_all_constraints_for_dimension(Hypertable *ht, int3
 extern int ts_chunk_delete_by_hypertable_id(int32 hypertable_id);
 extern TSDLLEXPORT int ts_chunk_delete_by_name(const char *schema, const char *table,
 											   DropBehavior behavior);
+extern int ts_chunk_delete_by_relid_and_relname(Oid relid, const char *schemaname,
+												const char *tablename, DropBehavior behavior,
+												bool preserve_chunk_catalog_row);
 extern bool ts_chunk_set_name(Chunk *chunk, const char *newname);
 extern bool ts_chunk_set_schema(Chunk *chunk, const char *newschema);
 extern TSDLLEXPORT List *ts_chunk_get_window(int32 dimension_id, int64 point, int count,

src/dimension.c

@@ -18,6 +18,7 @@
 #include <utils/timestamp.h>
 
 #include "compat/compat.h"
+#include "chunk.h"
 #include "cross_module_fn.h"
 #include "debug_point.h"
 #include "dimension.h"

src/process_utility.c

@@ -2247,7 +2247,9 @@ process_rename_column(ProcessUtilityArgs *args, Cache *hcache, Oid relid, Rename
 	 * */
 	if (ht)
 	{
-		ts_compression_settings_rename_column_hypertable(ht, stmt->subname, stmt->newname);
+		ts_compression_settings_rename_column_cascade(ht->main_table_relid,
+													  stmt->subname,
+													  stmt->newname);
 		add_hypertable_to_process_args(args, ht);
 		dim = ts_hyperspace_get_mutable_dimension_by_name(ht->space,
 														  DIMENSION_TYPE_ANY,
@@ -4959,9 +4961,22 @@ process_drop_table(EventTriggerDropObject *obj)
 	EventTriggerDropRelation *table = (EventTriggerDropRelation *) obj;
 
 	Assert(obj->type == EVENT_TRIGGER_DROP_TABLE || obj->type == EVENT_TRIGGER_DROP_FOREIGN_TABLE);
+	ts_chunk_delete_by_relid_and_relname(table->relid,
+										 table->schema,
+										 table->name,
+										 DROP_RESTRICT,
+										 false);
 	ts_hypertable_delete_by_name(table->schema, table->name);
-	ts_chunk_delete_by_name(table->schema, table->name, DROP_RESTRICT);
-	ts_compression_settings_delete(table->relid);
+	/*
+	 * Normally, compression settings are cleaned up when deleting the
+	 * hypertable or chunk. However, in some cases, e.g., when a hypertable
+	 * delete cascades to chunks, the chunk relids cannot be resolved from the
+	 * schema and name because the chunk relations are already dropped by
+	 * PostgreSQL when the "drop eventtrigger" is called. Therefore, also try
+	 * to delete compression settings here since the eventtrigger gives us the
+	 * relid of dropped objects.
+	 */
+	ts_compression_settings_delete_any(table->relid);
 }
 
 static void

src/ts_catalog/catalog.c

@@ -248,6 +248,7 @@ static const TableIndexDef catalog_table_index_definitions[_MAX_CATALOG_TABLES]
 		.length =  _MAX_COMPRESSION_SETTINGS_INDEX,
 		.names = (char *[]) {
 			[COMPRESSION_SETTINGS_PKEY] = "compression_settings_pkey",
+			[COMPRESSION_SETTINGS_COMPRESS_RELID_IDX] = "compression_settings_compress_relid_idx",
 		},
 	},
 	[COMPRESSION_CHUNK_SIZE] = {

src/ts_catalog/catalog.h

@@ -1155,6 +1155,7 @@ typedef enum Anum_continuous_aggs_watermark_pkey
 typedef enum Anum_compression_settings
 {
 	Anum_compression_settings_relid = 1,
+	Anum_compression_settings_compress_relid,
 	Anum_compression_settings_segmentby,
 	Anum_compression_settings_orderby,
 	Anum_compression_settings_orderby_desc,
@@ -1167,6 +1168,7 @@ typedef enum Anum_compression_settings
 typedef struct FormData_compression_settings
 {
 	Oid relid;
+	Oid compress_relid;
 	ArrayType *segmentby;
 	ArrayType *orderby;
 	ArrayType *orderby_desc;
@@ -1178,6 +1180,7 @@ typedef FormData_compression_settings *Form_compression_settings;
 enum
 {
 	COMPRESSION_SETTINGS_PKEY = 0,
+	COMPRESSION_SETTINGS_COMPRESS_RELID_IDX,
 	_MAX_COMPRESSION_SETTINGS_INDEX,
 };
 
@@ -1189,6 +1192,15 @@ typedef enum Anum_compression_settings_pkey
 
 #define Natts_compression_chunk_size_pkey (_Anum_compression_chunk_size_pkey_max - 1)
 
+typedef enum Anum_compression_settings_compress_relid_idx
+{
+	Anum_compression_settings_compress_relid_idx_relid = 1,
+	_Anum_compression_settings_compress_relid_idx_max,
+} Anum_compression_settings_compress_relid_idx;
+
+#define Natts_compression_settings_compress_relid_idx                                              \
+	(_Anum_compression_settings_compress_relid_idx_max - 1)
+
 #define COMPRESSION_CHUNK_SIZE_TABLE_NAME "compression_chunk_size"
 typedef enum Anum_compression_chunk_size
 {