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proposal: Introduction a commontype as new polymorphic type
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* proposal: Introduction a commontype as new polymorphic type
@ 2017-04-04 07:11  Pavel Stehule <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: Pavel Stehule @ 2017-04-04 07:11 UTC (permalink / raw)
  To: pgsql-hackers

Hi

I am still little bit unhappy with missing functionality in our generic
types.

If I write function fx(anyelement, anyelement) returns anyelement

postgres=# create or replace function fx(anyelement, anyelement) returns
anyelement
as $$ select greather($1,$2) $$ language sql;
CREATE FUNCTION
postgres=# select fx(1,1.1);
ERROR:  function fx(integer, numeric) does not exist
LINE 1: select fx(1,1.1);
               ^
It fails on basic example.

What do you think about introduction new similar polymorphic type, that
will use common type for real parameters?

some like

create or replace function fx(anyvalue, anyvalue) returns anyvalue
create or replace function fx(anyvalue[]) returns anyvalue

Using "any" and casting inside function has significant negative impact on
performance

Regards

Pavel


^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
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Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
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Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 06/10] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
 filename="v24-0007-Add-support-for-PRESERVE.patch"
Content-Transfer-Encoding: 8bit



^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
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Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 06/10] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
 filename="v24-0007-Add-support-for-PRESERVE.patch"
Content-Transfer-Encoding: 8bit



^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 06/10] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
 filename="v24-0007-Add-support-for-PRESERVE.patch"
Content-Transfer-Encoding: 8bit



^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 06/10] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
 filename="v24-0007-Add-support-for-PRESERVE.patch"
Content-Transfer-Encoding: 8bit



^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
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Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 06/10] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
 filename="v24-0007-Add-support-for-PRESERVE.patch"
Content-Transfer-Encoding: 8bit



^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
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Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 06/10] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--m51xatjYGsM+13rf
Content-Type: text/x-diff; charset=iso-8859-1
Content-Disposition: attachment;
 filename="v24-0007-Add-support-for-PRESERVE.patch"
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 6/7] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--YZ5djTAD1cGYuMQK
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Content-Disposition: attachment;
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^ permalink  raw  reply  [nested|flat] 122+ messages in thread

* [PATCH v24 06/10] alter table set compression
@ 2020-12-18 06:01  dilipkumar <[email protected]>
  0 siblings, 0 replies; 122+ messages in thread

From: dilipkumar @ 2020-12-18 06:01 UTC (permalink / raw)

Add support for changing the compression method associated
with a column, forcing a table rewrite.

Dilip Kumar based on the patches from Ildus Kurbangaliev.
Design input from Robert Haas and Tomas Vondra.
Reviewed by Robert Haas, Tomas Vondra, Alexander Korotkov

Discussions:
https://www.postgresql.org/message-id/[email protected]
https://www.postgresql.org/message-id/CA%2BTgmoaKDW1Oi9V%3Djc9hOGyf77NbkNEABuqgHD1Cq%3D%3D1QsOcxg%40...
https://www.postgresql.org/message-id/CA%2BTgmobSDVgUage9qQ5P_%3DF_9jaMkCgyKxUQGtFQU7oN4kX-AA%40mail...
https://www.postgresql.org/message-id/20201005160355.byp74sh3ejsv7wrj%40development
https://www.postgresql.org/message-id/CAFiTN-tzTTT2oqWdRGLv1dvvS5MC1W%2BLE%2B3bqWPJUZj4GnHOJg%40mail...
---
 doc/src/sgml/ref/alter_table.sgml           |  16 ++
 src/backend/commands/createas.c             |   3 +-
 src/backend/commands/matview.c              |   3 +-
 src/backend/commands/tablecmds.c            | 226 +++++++++++++++-----
 src/backend/executor/nodeModifyTable.c      |   9 +-
 src/backend/parser/gram.y                   |   9 +
 src/bin/psql/tab-complete.c                 |   2 +-
 src/include/commands/event_trigger.h        |   1 +
 src/include/executor/executor.h             |   3 +-
 src/include/nodes/parsenodes.h              |   3 +-
 src/test/regress/expected/compression.out   |  93 ++++++--
 src/test/regress/expected/compression_1.out |  56 ++++-
 src/test/regress/sql/compression.sql        |  21 ++
 13 files changed, 370 insertions(+), 75 deletions(-)

diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..0bd0c1a503 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -54,6 +54,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET ( <replaceable class="parameter">attribute_option</replaceable> = <replaceable class="parameter">value</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> RESET ( <replaceable class="parameter">attribute_option</replaceable> [, ... ] )
     ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET STORAGE { PLAIN | EXTERNAL | EXTENDED | MAIN }
+    ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET COMPRESSION <replaceable class="parameter">compression_method</replaceable>
     ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]
     ADD <replaceable class="parameter">table_constraint_using_index</replaceable>
     ALTER CONSTRAINT <replaceable class="parameter">constraint_name</replaceable> [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -103,6 +104,7 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
   GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ] |
   UNIQUE <replaceable class="parameter">index_parameters</replaceable> |
   PRIMARY KEY <replaceable class="parameter">index_parameters</replaceable> |
+  COMPRESSION <replaceable class="parameter">compression_method</replaceable> |
   REFERENCES <replaceable class="parameter">reftable</replaceable> [ ( <replaceable class="parameter">refcolumn</replaceable> ) ] [ MATCH FULL | MATCH PARTIAL | MATCH SIMPLE ]
     [ ON DELETE <replaceable class="parameter">referential_action</replaceable> ] [ ON UPDATE <replaceable class="parameter">referential_action</replaceable> ] }
 [ DEFERRABLE | NOT DEFERRABLE ] [ INITIALLY DEFERRED | INITIALLY IMMEDIATE ]
@@ -383,6 +385,20 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
     </listitem>
    </varlistentry>
 
+   <varlistentry>
+    <term>
+     <literal>SET COMPRESSION <replaceable class="parameter">compression_method</replaceable></literal>
+    </term>
+    <listitem>
+     <para>
+      This sets the compression method for a column.  The supported compression
+      methods are <literal>pglz</literal> and <literal>lz4</literal>.
+      <literal>lz4</literal> is available only if <literal>--with-lz4</literal>
+      was used when building <productname>PostgreSQL</productname>.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry>
     <term><literal>ADD <replaceable class="parameter">table_constraint</replaceable> [ NOT VALID ]</literal></term>
     <listitem>
diff --git a/src/backend/commands/createas.c b/src/backend/commands/createas.c
index 1d17dc0d6b..748ec29570 100644
--- a/src/backend/commands/createas.c
+++ b/src/backend/commands/createas.c
@@ -589,7 +589,8 @@ intorel_receive(TupleTableSlot *slot, DestReceiver *self)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 													 &myState->decompress_tuple_slot,
-													 myState->rel->rd_att);
+													 myState->rel->rd_att,
+													 NULL);
 
 		/*
 		 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 713fc3fceb..779b4e51cf 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -494,7 +494,8 @@ transientrel_receive(TupleTableSlot *slot, DestReceiver *self)
 	 */
 	slot = CompareCompressionMethodAndDecompress(slot,
 												 &myState->decompress_tuple_slot,
-												 myState->transientrel->rd_att);
+												 myState->transientrel->rd_att,
+												 NULL);
 
 	/*
 	 * Note that the input slot might not be of the type of the target
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 72ba017814..586a92f0c1 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -529,6 +529,8 @@ static void ATExecGenericOptions(Relation rel, List *options);
 static void ATExecEnableRowSecurity(Relation rel);
 static void ATExecDisableRowSecurity(Relation rel);
 static void ATExecForceNoForceRowSecurity(Relation rel, bool force_rls);
+static ObjectAddress ATExecSetCompression(AlteredTableInfo *tab, Relation rel,
+					 const char *column, Node *newValue, LOCKMODE lockmode);
 
 static void index_copy_data(Relation rel, RelFileNode newrnode);
 static const char *storage_name(char c);
@@ -3968,6 +3970,7 @@ AlterTableGetLockLevel(List *cmds)
 				 */
 			case AT_GenericOptions:
 			case AT_AlterColumnGenericOptions:
+			case AT_SetCompression:
 				cmd_lockmode = AccessExclusiveLock;
 				break;
 
@@ -4495,7 +4498,8 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 		case AT_DisableRowSecurity:
 		case AT_ForceRowSecurity:
 		case AT_NoForceRowSecurity:
-			ATSimplePermissions(rel, ATT_TABLE);
+		case AT_SetCompression:
+			ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW);
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -4903,6 +4907,10 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 			Assert(rel->rd_rel->relkind == RELKIND_INDEX);
 			ATExecAlterCollationRefreshVersion(rel, cmd->object);
 			break;
+		case AT_SetCompression:
+			address = ATExecSetCompression(tab, rel, cmd->name, cmd->def,
+										   lockmode);
+			break;
 		default:				/* oops */
 			elog(ERROR, "unrecognized alter table type: %d",
 				 (int) cmd->subtype);
@@ -5519,6 +5527,7 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 
 		while (table_scan_getnextslot(scan, ForwardScanDirection, oldslot))
 		{
+			bool		decompressed = false;
 			TupleTableSlot *insertslot;
 
 			if (tab->rewrite > 0)
@@ -5527,11 +5536,25 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
 				slot_getallattrs(oldslot);
 				ExecClearTuple(newslot);
 
-				/* copy attributes */
-				memcpy(newslot->tts_values, oldslot->tts_values,
-					   sizeof(Datum) * oldslot->tts_nvalid);
-				memcpy(newslot->tts_isnull, oldslot->tts_isnull,
-					   sizeof(bool) * oldslot->tts_nvalid);
+				if (tab->rewrite & AT_REWRITE_ALTER_COMPRESSION)
+					(void) CompareCompressionMethodAndDecompress(oldslot,
+																 &newslot,
+																 newTupDesc,
+																 &decompressed);
+
+				/*
+				 * copy attributes, if we have decompressed some attribute then
+				 * the values and nulls array is already copied
+				 */
+				if (!decompressed)
+				{
+					memcpy(newslot->tts_values, oldslot->tts_values,
+						   sizeof(Datum) * oldslot->tts_nvalid);
+					memcpy(newslot->tts_isnull, oldslot->tts_isnull,
+						   sizeof(bool) * oldslot->tts_nvalid);
+				}
+				else
+					ExecClearTuple(newslot);
 
 				/* Set dropped attributes to null in new tuple */
 				foreach(lc, dropped_attrs)
@@ -7767,6 +7790,67 @@ ATExecSetOptions(Relation rel, const char *colName, Node *options,
 	return address;
 }
 
+/*
+ * Helper function for ATExecSetStorage and ATExecSetCompression
+ *
+ * Set the attcompression and attstorage for the respective index attribute if
+ * the respective input values are valid.
+ */
+static void
+ApplyChangesToIndexes(Relation rel, Relation attrelation, AttrNumber attnum,
+					  Oid newcompression, char newstorage, LOCKMODE lockmode)
+{
+	HeapTuple	tuple;
+	ListCell   *lc;
+	Form_pg_attribute attrtuple;
+
+	foreach(lc, RelationGetIndexList(rel))
+	{
+		Oid			indexoid = lfirst_oid(lc);
+		Relation	indrel;
+		AttrNumber	indattnum = 0;
+
+		indrel = index_open(indexoid, lockmode);
+
+		for (int i = 0; i < indrel->rd_index->indnatts; i++)
+		{
+			if (indrel->rd_index->indkey.values[i] == attnum)
+			{
+				indattnum = i + 1;
+				break;
+			}
+		}
+
+		if (indattnum == 0)
+		{
+			index_close(indrel, lockmode);
+			continue;
+		}
+
+		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
+
+		if (HeapTupleIsValid(tuple))
+		{
+			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
+
+			if (OidIsValid(newcompression))
+				attrtuple->attcompression = newcompression;
+
+			if (newstorage != '\0')
+				attrtuple->attstorage = newstorage;
+
+			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
+
+			InvokeObjectPostAlterHook(RelationRelationId,
+									  RelationGetRelid(rel),
+									  attrtuple->attnum);
+
+			heap_freetuple(tuple);
+		}
+
+		index_close(indrel, lockmode);
+	}
+}
 /*
  * ALTER TABLE ALTER COLUMN SET STORAGE
  *
@@ -7782,7 +7866,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	Form_pg_attribute attrtuple;
 	AttrNumber	attnum;
 	ObjectAddress address;
-	ListCell   *lc;
 
 	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
@@ -7846,47 +7929,8 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	 * Apply the change to indexes as well (only for simple index columns,
 	 * matching behavior of index.c ConstructTupleDescriptor()).
 	 */
-	foreach(lc, RelationGetIndexList(rel))
-	{
-		Oid			indexoid = lfirst_oid(lc);
-		Relation	indrel;
-		AttrNumber	indattnum = 0;
-
-		indrel = index_open(indexoid, lockmode);
-
-		for (int i = 0; i < indrel->rd_index->indnatts; i++)
-		{
-			if (indrel->rd_index->indkey.values[i] == attnum)
-			{
-				indattnum = i + 1;
-				break;
-			}
-		}
-
-		if (indattnum == 0)
-		{
-			index_close(indrel, lockmode);
-			continue;
-		}
-
-		tuple = SearchSysCacheCopyAttNum(RelationGetRelid(indrel), indattnum);
-
-		if (HeapTupleIsValid(tuple))
-		{
-			attrtuple = (Form_pg_attribute) GETSTRUCT(tuple);
-			attrtuple->attstorage = newstorage;
-
-			CatalogTupleUpdate(attrelation, &tuple->t_self, tuple);
-
-			InvokeObjectPostAlterHook(RelationRelationId,
-									  RelationGetRelid(rel),
-									  attrtuple->attnum);
-
-			heap_freetuple(tuple);
-		}
-
-		index_close(indrel, lockmode);
-	}
+	ApplyChangesToIndexes(rel, attrelation, attnum, InvalidOid, newstorage,
+						  lockmode);
 
 	table_close(attrelation, RowExclusiveLock);
 
@@ -15033,6 +15077,92 @@ ATExecGenericOptions(Relation rel, List *options)
 	heap_freetuple(tuple);
 }
 
+/*
+ * ALTER TABLE ALTER COLUMN SET COMPRESSION
+ *
+ * Return value is the address of the modified column
+ */
+static ObjectAddress
+ATExecSetCompression(AlteredTableInfo *tab,
+					 Relation rel,
+					 const char *column,
+					 Node *newValue,
+					 LOCKMODE lockmode)
+{
+	Relation	attrel;
+	HeapTuple	tuple;
+	Form_pg_attribute atttableform;
+	AttrNumber	attnum;
+	char	   *compression;
+	char		typstorage;
+	Oid			cmoid;
+	Datum		values[Natts_pg_attribute];
+	bool		nulls[Natts_pg_attribute];
+	bool		replace[Natts_pg_attribute];
+	ObjectAddress address;
+
+	Assert(IsA(newValue, String));
+	compression = strVal(newValue);
+
+	attrel = table_open(AttributeRelationId, RowExclusiveLock);
+
+	tuple = SearchSysCacheAttName(RelationGetRelid(rel), column);
+	if (!HeapTupleIsValid(tuple))
+		ereport(ERROR,
+				(errcode(ERRCODE_UNDEFINED_COLUMN),
+				 errmsg("column \"%s\" of relation \"%s\" does not exist",
+						column, RelationGetRelationName(rel))));
+
+	/* Prevent them from altering a system attribute */
+	atttableform = (Form_pg_attribute) GETSTRUCT(tuple);
+	attnum = atttableform->attnum;
+	if (attnum <= 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("cannot alter system column \"%s\"", column)));
+
+	typstorage = get_typstorage(atttableform->atttypid);
+
+	/* Prevent from setting compression methods for uncompressible type */
+	if (!IsStorageCompressible(typstorage))
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+					errmsg("column data type %s does not support compression",
+						format_type_be(atttableform->atttypid))));
+
+	/* Initialize buffers for new tuple values */
+	memset(values, 0, sizeof(values));
+	memset(nulls, false, sizeof(nulls));
+	memset(replace, false, sizeof(replace));
+
+	/* Get the attribute compression method. */
+	cmoid = GetAttributeCompression(atttableform, compression);
+
+	if (atttableform->attcompression != cmoid)
+		tab->rewrite |= AT_REWRITE_ALTER_COMPRESSION;
+
+	atttableform->attcompression = cmoid;
+	CatalogTupleUpdate(attrel, &tuple->t_self, tuple);
+
+	InvokeObjectPostAlterHook(RelationRelationId,
+							  RelationGetRelid(rel),
+							  atttableform->attnum);
+
+	ReleaseSysCache(tuple);
+
+	/* apply changes to the index column as well */
+	ApplyChangesToIndexes(rel, attrel, attnum, cmoid, '\0', lockmode);
+	table_close(attrel, RowExclusiveLock);
+
+	/* make changes visible */
+	CommandCounterIncrement();
+
+	ObjectAddressSubSet(address, RelationRelationId,
+						RelationGetRelid(rel), atttableform->attnum);
+	return address;
+}
+
+
 /*
  * Preparation phase for SET LOGGED/UNLOGGED
  *
diff --git a/src/backend/executor/nodeModifyTable.c b/src/backend/executor/nodeModifyTable.c
index 920d9dd0d5..ea82a05591 100644
--- a/src/backend/executor/nodeModifyTable.c
+++ b/src/backend/executor/nodeModifyTable.c
@@ -2052,7 +2052,8 @@ ExecPrepareTupleRouting(ModifyTableState *mtstate,
 TupleTableSlot *
 CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 									  TupleTableSlot **outslot,
-									  TupleDesc targetTupDesc)
+									  TupleDesc targetTupDesc,
+									  bool *decompressed)
 {
 	int			i;
 	int			attnum;
@@ -2139,6 +2140,9 @@ CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 
 		*outslot = newslot;
 
+		if (decompressed != NULL)
+			*decompressed = true;
+
 		return newslot;
 	}
 
@@ -2360,7 +2364,8 @@ ExecModifyTable(PlanState *pstate)
 		 */
 		slot = CompareCompressionMethodAndDecompress(slot,
 									&node->mt_decompress_tuple_slot,
-									resultRelInfo->ri_RelationDesc->rd_att);
+									resultRelInfo->ri_RelationDesc->rd_att,
+									NULL);
 
 		switch (operation)
 		{
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 52d92df25d..30acfe615d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2308,6 +2308,15 @@ alter_table_cmd:
 					n->missing_ok = true;
 					$$ = (Node *)n;
 				}
+			/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET (COMPRESSION <cm>) */
+			| ALTER opt_column ColId SET optColumnCompression
+				{
+					AlterTableCmd *n = makeNode(AlterTableCmd);
+					n->subtype = AT_SetCompression;
+					n->name = $3;
+					n->def = (Node *) makeString($5);
+					$$ = (Node *)n;
+				}
 			/* ALTER TABLE <name> DROP [COLUMN] IF EXISTS <colname> [RESTRICT|CASCADE] */
 			| DROP opt_column IF_P EXISTS ColId opt_drop_behavior
 				{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 1e1c315bae..ffa8d05edf 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2098,7 +2098,7 @@ psql_completion(const char *text, int start, int end)
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET"))
-		COMPLETE_WITH("(", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
+		COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "NOT NULL", "STATISTICS", "STORAGE");
 	/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
 	else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "(") ||
 			 Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "("))
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..5a314f4c1d 100644
--- a/src/include/commands/event_trigger.h
+++ b/src/include/commands/event_trigger.h
@@ -32,6 +32,7 @@ typedef struct EventTriggerData
 #define AT_REWRITE_ALTER_PERSISTENCE	0x01
 #define AT_REWRITE_DEFAULT_VAL			0x02
 #define AT_REWRITE_COLUMN_REWRITE		0x04
+#define AT_REWRITE_ALTER_COMPRESSION	0x08
 
 /*
  * EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/executor/executor.h b/src/include/executor/executor.h
index 6495162a33..050ef2dcd0 100644
--- a/src/include/executor/executor.h
+++ b/src/include/executor/executor.h
@@ -623,5 +623,6 @@ extern void CheckSubscriptionRelkind(char relkind, const char *nspname,
 									 const char *relname);
 extern TupleTableSlot *CompareCompressionMethodAndDecompress(TupleTableSlot *slot,
 												  TupleTableSlot **outslot,
-												  TupleDesc targetTupDesc);
+												  TupleDesc targetTupDesc,
+												  bool *decompressed);
 #endif							/* EXECUTOR_H  */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 19d2ba26bf..f9a87dee02 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1901,7 +1901,8 @@ typedef enum AlterTableType
 	AT_AddIdentity,				/* ADD IDENTITY */
 	AT_SetIdentity,				/* SET identity column options */
 	AT_DropIdentity,			/* DROP IDENTITY */
-	AT_AlterCollationRefreshVersion /* ALTER COLLATION ... REFRESH VERSION */
+	AT_AlterCollationRefreshVersion, /* ALTER COLLATION ... REFRESH VERSION */
+	AT_SetCompression			/* SET COMPRESSION */
 } AlterTableType;
 
 typedef struct ReplicaIdentityStmt
diff --git a/src/test/regress/expected/compression.out b/src/test/regress/expected/compression.out
index 167878e78b..21c1b451d2 100644
--- a/src/test/regress/expected/compression.out
+++ b/src/test/regress/expected/compression.out
@@ -4,20 +4,20 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
 CREATE TABLE cmdata1(f1 TEXT COMPRESSION lz4);
 INSERT INTO cmdata1 VALUES(repeat('1234567890',1004));
 \d+ cmdata1
-                                 Table "public.cmdata1"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata1"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- try setting compression for incompressible data type
 CREATE TABLE cmdata2 (f1 int COMPRESSION pglz);
@@ -112,18 +112,18 @@ DROP TABLE cmdata2;
 -- test LIKE INCLUDING COMPRESSION
 CREATE TABLE cmdata2 (LIKE cmdata1 INCLUDING COMPRESSION);
 \d+ cmdata2
-                                 Table "public.cmdata2"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata2"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
 
 -- test compression with materialized view
 CREATE MATERIALIZED VIEW mv(x) AS SELECT * FROM cmdata1;
 \d+ mv
-                             Materialized view "public.mv"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- x      | text |           |          |         | extended |              | 
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | pglz        |              | 
 View definition:
  SELECT cmdata1.f1 AS x
    FROM cmdata1;
@@ -165,6 +165,67 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | lz4         |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ lz4
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+                                    Materialized view "public.mv"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ x      | text |           |          |         | extended | lz4         |              | 
+View definition:
+ SELECT cmdata1.f1 AS x
+   FROM cmdata1;
+
+SELECT pg_column_compression(f1) FROM cmdata1;
+ pg_column_compression 
+-----------------------
+ pglz
+ pglz
+(2 rows)
+
+SELECT pg_column_compression(x) FROM mv;
+ pg_column_compression 
+-----------------------
+ lz4
+ lz4
+(2 rows)
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ lz4
+ pglz
+(2 rows)
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+ pg_column_compression 
+-----------------------
+ pglz
+ lz4
+(2 rows)
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/expected/compression_1.out b/src/test/regress/expected/compression_1.out
index 329e7881b0..64c5855bf7 100644
--- a/src/test/regress/expected/compression_1.out
+++ b/src/test/regress/expected/compression_1.out
@@ -4,10 +4,10 @@ CREATE TABLE cmdata(f1 text COMPRESSION pglz);
 CREATE INDEX idx ON cmdata(f1);
 INSERT INTO cmdata VALUES(repeat('1234567890',1000));
 \d+ cmdata
-                                 Table "public.cmdata"
- Column | Type | Collation | Nullable | Default | Storage  | Stats target | Description 
---------+------+-----------+----------+---------+----------+--------------+-------------
- f1     | text |           |          |         | extended |              | 
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
 Indexes:
     "idx" btree (f1)
 
@@ -157,6 +157,54 @@ CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 NOTICE:  merging column "f1" with inherited definition
 ERROR:  column "f1" has a compression method conflict
 DETAIL:  pglz versus lz4
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+\d+ cmdata
+                                        Table "public.cmdata"
+ Column | Type | Collation | Nullable | Default | Storage  | Compression | Stats target | Description 
+--------+------+-----------+----------+---------+----------+-------------+--------------+-------------
+ f1     | text |           |          |         | extended | pglz        |              | 
+Indexes:
+    "idx" btree (f1)
+
+SELECT pg_column_compression(f1) FROM cmdata;
+ pg_column_compression 
+-----------------------
+ pglz
+(1 row)
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmdata1" does not exist
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+ERROR:  relation "mv" does not exist
+REFRESH MATERIALIZED VIEW mv;
+ERROR:  relation "mv" does not exist
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+ERROR:  relation "cmdata1" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmdata1;
+                                              ^
+SELECT pg_column_compression(x) FROM mv;
+ERROR:  relation "mv" does not exist
+LINE 1: SELECT pg_column_compression(x) FROM mv;
+                                             ^
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart" does not exist
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ERROR:  relation "cmpart1" does not exist
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+ERROR:  not built with lz4 support
+SELECT pg_column_compression(f1) FROM cmpart;
+ERROR:  relation "cmpart" does not exist
+LINE 1: SELECT pg_column_compression(f1) FROM cmpart;
+                                              ^
 -- check data is ok
 SELECT length(f1) FROM cmdata;
  length 
diff --git a/src/test/regress/sql/compression.sql b/src/test/regress/sql/compression.sql
index 450416ecb4..b9daa33b74 100644
--- a/src/test/regress/sql/compression.sql
+++ b/src/test/regress/sql/compression.sql
@@ -75,6 +75,27 @@ SELECT pg_column_compression(f1) FROM cmpart;
 CREATE TABLE cminh() INHERITS(cmdata, cmdata1);
 CREATE TABLE cminh(f1 TEXT COMPRESSION lz4) INHERITS(cmdata);
 
+-- test alter compression method with rewrite
+ALTER TABLE cmdata ALTER COLUMN f1 SET COMPRESSION lz4;
+\d+ cmdata
+SELECT pg_column_compression(f1) FROM cmdata;
+
+-- test alter compression method for the materialized view
+ALTER TABLE cmdata1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER MATERIALIZED VIEW mv ALTER COLUMN x SET COMPRESSION lz4;
+REFRESH MATERIALIZED VIEW mv;
+\d+ mv
+SELECT pg_column_compression(f1) FROM cmdata1;
+SELECT pg_column_compression(x) FROM mv;
+
+-- test alter compression method for the partitioned table
+ALTER TABLE cmpart ALTER COLUMN f1 SET COMPRESSION pglz;
+SELECT pg_column_compression(f1) FROM cmpart;
+
+ALTER TABLE cmpart1 ALTER COLUMN f1 SET COMPRESSION pglz;
+ALTER TABLE cmpart2 ALTER COLUMN f1 SET COMPRESSION lz4;
+SELECT pg_column_compression(f1) FROM cmpart;
+
 -- check data is ok
 SELECT length(f1) FROM cmdata;
 SELECT length(f1) FROM cmdata1;
-- 
2.17.0


--m51xatjYGsM+13rf
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