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help / color / mirror / Atom feedFrom: Justin Pryzby <[email protected]>
Subject: [PATCH v2 1/3] ALTER TABLE SET ACCESS METHOD
Date: Sat, 27 Feb 2021 20:40:54 -0600
This does a tuple-level rewrite to the new AM
---
doc/src/sgml/ref/alter_table.sgml | 11 ++++
src/backend/commands/cluster.c | 17 ++++--
src/backend/commands/matview.c | 1 +
src/backend/commands/tablecmds.c | 76 ++++++++++++++++++++++---
src/backend/parser/gram.y | 8 +++
src/bin/psql/tab-complete.c | 11 ++--
src/include/commands/cluster.h | 2 +-
src/include/commands/event_trigger.h | 1 +
src/include/nodes/parsenodes.h | 1 +
src/test/regress/expected/create_am.out | 16 ++++++
src/test/regress/sql/create_am.sql | 6 ++
11 files changed, 131 insertions(+), 19 deletions(-)
diff --git a/doc/src/sgml/ref/alter_table.sgml b/doc/src/sgml/ref/alter_table.sgml
index c25ef5abd6..38e416d183 100644
--- a/doc/src/sgml/ref/alter_table.sgml
+++ b/doc/src/sgml/ref/alter_table.sgml
@@ -74,6 +74,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
CLUSTER ON <replaceable class="parameter">index_name</replaceable>
SET WITHOUT CLUSTER
SET WITHOUT OIDS
+ SET ACCESS METHOD <replaceable class="parameter">new_access_method</replaceable>
SET TABLESPACE <replaceable class="parameter">new_tablespace</replaceable>
SET { LOGGED | UNLOGGED }
SET ( <replaceable class="parameter">storage_parameter</replaceable> [= <replaceable class="parameter">value</replaceable>] [, ... ] )
@@ -658,6 +659,16 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><literal>SET ACCESS METHOD</literal></term>
+ <listitem>
+ <para>
+ This form changes the table's access method to the specified table AM and
+ rewrites the table.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry>
<term><literal>SET TABLESPACE</literal></term>
<listitem>
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 096a06f7b3..426a5b83ba 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -577,6 +577,7 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
{
Oid tableOid = RelationGetRelid(OldHeap);
Oid tableSpace = OldHeap->rd_rel->reltablespace;
+ Oid accessMethod = OldHeap->rd_rel->relam;
Oid OIDNewHeap;
char relpersistence;
bool is_system_catalog;
@@ -598,6 +599,7 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
/* Create the transient table that will receive the re-ordered data */
OIDNewHeap = make_new_heap(tableOid, tableSpace,
relpersistence,
+ accessMethod,
AccessExclusiveLock);
/* Copy the heap data into the new table in the desired order */
@@ -619,15 +621,15 @@ rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
* Create the transient table that will be filled with new data during
* CLUSTER, ALTER TABLE, and similar operations. The transient table
* duplicates the logical structure of the OldHeap, but is placed in
- * NewTableSpace which might be different from OldHeap's. Also, it's built
- * with the specified persistence, which might differ from the original's.
+ * NewTableSpace/accessMethod/persistence, which might differ from those
+ * of the OldHeap.
*
* After this, the caller should load the new heap with transferred/modified
* data, then call finish_heap_swap to complete the operation.
*/
Oid
make_new_heap(Oid OIDOldHeap, Oid NewTableSpace, char relpersistence,
- LOCKMODE lockmode)
+ Oid relam, LOCKMODE lockmode)
{
TupleDesc OldHeapDesc;
char NewHeapName[NAMEDATALEN];
@@ -686,7 +688,7 @@ make_new_heap(Oid OIDOldHeap, Oid NewTableSpace, char relpersistence,
InvalidOid,
InvalidOid,
OldHeap->rd_rel->relowner,
- OldHeap->rd_rel->relam,
+ relam,
OldHeapDesc,
NIL,
RELKIND_RELATION,
@@ -1036,6 +1038,10 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
relform1->reltablespace = relform2->reltablespace;
relform2->reltablespace = swaptemp;
+ swaptemp = relform1->relam;
+ relform1->relam = relform2->relam;
+ relform2->relam = swaptemp;
+
swptmpchr = relform1->relpersistence;
relform1->relpersistence = relform2->relpersistence;
relform2->relpersistence = swptmpchr;
@@ -1071,6 +1077,9 @@ swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
if (relform1->relpersistence != relform2->relpersistence)
elog(ERROR, "cannot change persistence of mapped relation \"%s\"",
NameStr(relform1->relname));
+ if (relform1->relam != relform2->relam)
+ elog(ERROR, "cannot change access method of mapped relation \"%s\"",
+ NameStr(relform1->relname));
if (!swap_toast_by_content &&
(relform1->reltoastrelid || relform2->reltoastrelid))
elog(ERROR, "cannot swap toast by links for mapped relation \"%s\"",
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index c5c25ce11d..c206eaab7c 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -299,6 +299,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
* will be gone).
*/
OIDNewHeap = make_new_heap(matviewOid, tableSpace, relpersistence,
+ matviewRel->rd_rel->relam,
ExclusiveLock);
LockRelationOid(OIDNewHeap, AccessExclusiveLock);
dest = CreateTransientRelDestReceiver(OIDNewHeap);
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 559fa1d2e5..4f62f062fa 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -18,6 +18,7 @@
#include "access/genam.h"
#include "access/heapam.h"
#include "access/heapam_xlog.h"
+#include "access/heaptoast.h"
#include "access/multixact.h"
#include "access/reloptions.h"
#include "access/relscan.h"
@@ -164,6 +165,7 @@ typedef struct AlteredTableInfo
List *afterStmts; /* List of utility command parsetrees */
bool verify_new_notnull; /* T if we should recheck NOT NULL */
int rewrite; /* Reason for forced rewrite, if any */
+ Oid newAccessMethod; /* new table access method; 0 means no change */
Oid newTableSpace; /* new tablespace; 0 means no change */
bool chgPersistence; /* T if SET LOGGED/UNLOGGED is used */
char newrelpersistence; /* if above is true */
@@ -507,6 +509,7 @@ static void ATExecDropCluster(Relation rel, LOCKMODE lockmode);
static bool ATPrepChangePersistence(Relation rel, bool toLogged);
static void ATPrepSetTableSpace(AlteredTableInfo *tab, Relation rel,
const char *tablespacename, LOCKMODE lockmode);
+static void ATPrepSetAccessMethod(AlteredTableInfo *tab, Relation rel, const char *amname, LOCKMODE lockmode);
static void ATExecSetTableSpace(Oid tableOid, Oid newTableSpace, LOCKMODE lockmode);
static void ATExecSetTableSpaceNoStorage(Relation rel, Oid newTableSpace);
static void ATExecSetRelOptions(Relation rel, List *defList,
@@ -3874,6 +3877,7 @@ AlterTableGetLockLevel(List *cmds)
*/
case AT_AddColumn: /* may rewrite heap, in some cases and visible
* to SELECT */
+ case AT_SetAccessMethod: /* must rewrite heap */
case AT_SetTableSpace: /* must rewrite heap */
case AT_AlterColumnType: /* must rewrite heap */
cmd_lockmode = AccessExclusiveLock;
@@ -4384,6 +4388,13 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
ATSimplePermissions(rel, ATT_TABLE | ATT_FOREIGN_TABLE);
pass = AT_PASS_DROP;
break;
+ case AT_SetAccessMethod: /* SET ACCESS METHOD */
+ ATSimplePermissions(rel, ATT_TABLE);
+ /* This command never recurses */
+ tab->rewrite |= AT_REWRITE_ACCESS_METHOD;
+ ATPrepSetAccessMethod(tab, rel, cmd->name, lockmode);
+ pass = AT_PASS_MISC; /* doesn't actually matter */
+ break;
case AT_SetTableSpace: /* SET TABLESPACE */
ATSimplePermissions(rel, ATT_TABLE | ATT_MATVIEW | ATT_INDEX |
ATT_PARTITIONED_INDEX);
@@ -4739,6 +4750,9 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
case AT_DropOids: /* SET WITHOUT OIDS */
/* nothing to do here, oid columns don't exist anymore */
break;
+ case AT_SetAccessMethod: /* SET ACCESS METHOD */
+ /* Handled specially in Phase 3 */
+ break;
case AT_SetTableSpace: /* SET TABLESPACE */
/*
@@ -5066,7 +5080,7 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
/*
* We only need to rewrite the table if at least one column needs to
- * be recomputed, or we are changing its persistence.
+ * be recomputed, or we are changing its persistence or access method.
*
* There are two reasons for requiring a rewrite when changing
* persistence: on one hand, we need to ensure that the buffers
@@ -5080,6 +5094,7 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
/* Build a temporary relation and copy data */
Relation OldHeap;
Oid OIDNewHeap;
+ Oid NewAccessMethod;
Oid NewTableSpace;
char persistence;
@@ -5115,11 +5130,16 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
* Select destination tablespace (same as original unless user
* requested a change)
*/
- if (tab->newTableSpace)
+ if (OidIsValid(tab->newTableSpace))
NewTableSpace = tab->newTableSpace;
else
NewTableSpace = OldHeap->rd_rel->reltablespace;
+ if (OidIsValid(tab->newAccessMethod))
+ NewAccessMethod = tab->newAccessMethod;
+ else
+ NewAccessMethod = OldHeap->rd_rel->relam;
+
/*
* Select persistence of transient table (same as original unless
* user requested a change)
@@ -5160,7 +5180,7 @@ ATRewriteTables(AlterTableStmt *parsetree, List **wqueue, LOCKMODE lockmode,
* unlogged anyway.
*/
OIDNewHeap = make_new_heap(tab->relid, NewTableSpace, persistence,
- lockmode);
+ NewAccessMethod, lockmode);
/*
* Copy the heap data into the new table with the desired
@@ -5484,11 +5504,28 @@ 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);
+ /* Need to detoast tuples when changing AM XXX: should check if one AM is heap and one isn't? */
+ if (newrel->rd_rel->relam != oldrel->rd_rel->relam)
+ {
+ HeapTuple htup = toast_build_flattened_tuple(oldTupDesc,
+ oldslot->tts_values,
+ oldslot->tts_isnull);
+
+ /*
+ * Copy the value/null array to the new slot and materialize it,
+ * before clearing the tuple from the old slot.
+ */
+ heap_deform_tuple(htup, newslot->tts_tupleDescriptor,
+ newslot->tts_values, newslot->tts_isnull);
+ ExecStoreVirtualTuple(newslot);
+ ExecClearTuple(oldslot);
+ } else {
+ /* 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);
+ }
/* Set dropped attributes to null in new tuple */
foreach(lc, dropped_attrs)
@@ -5515,7 +5552,8 @@ ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode)
&newslot->tts_isnull[ex->attnum - 1]);
}
- ExecStoreVirtualTuple(newslot);
+ if (newrel->rd_rel->relam == oldrel->rd_rel->relam)
+ ExecStoreVirtualTuple(newslot);
/*
* Now, evaluate any expressions whose inputs come from the
@@ -13026,6 +13064,26 @@ ATExecDropCluster(Relation rel, LOCKMODE lockmode)
mark_index_clustered(rel, InvalidOid, false);
}
+/*
+ * ALTER TABLE SET ACCESS METHOD
+ */
+static void
+ATPrepSetAccessMethod(AlteredTableInfo *tab, Relation rel, const char *amname, LOCKMODE lockmode)
+{
+ Oid amoid;
+
+ /* Check that the AM exists */
+ amoid = get_table_am_oid(amname, false);
+
+ /* Save info for Phase 3 to do the real work */
+ if (OidIsValid(tab->newAccessMethod))
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("cannot have multiple SET ACCESS METHOD subcommands")));
+
+ tab->newAccessMethod = amoid;
+}
+
/*
* ALTER TABLE SET TABLESPACE
*/
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 652be0b96d..2ae41f8f4d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -2574,6 +2574,14 @@ alter_table_cmd:
n->newowner = $3;
$$ = (Node *)n;
}
+ /* ALTER TABLE <name> SET ACCESS METHOD <amname> */
+ | SET ACCESS METHOD name
+ {
+ AlterTableCmd *n = makeNode(AlterTableCmd);
+ n->subtype = AT_SetAccessMethod;
+ n->name = $4;
+ $$ = (Node *)n;
+ }
/* ALTER TABLE <name> SET TABLESPACE <tablespacename> */
| SET TABLESPACE name
{
diff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 9f0208ac49..4400b2e832 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -2143,13 +2143,14 @@ psql_completion(const char *text, int start, int end)
}
/* If we have ALTER TABLE <sth> SET, provide list of attributes and '(' */
else if (Matches("ALTER", "TABLE", MatchAny, "SET"))
- COMPLETE_WITH("(", "LOGGED", "SCHEMA", "TABLESPACE", "UNLOGGED",
- "WITH", "WITHOUT");
-
+ COMPLETE_WITH("(", "ACCESS METHOD", "LOGGED", "SCHEMA",
+ "TABLESPACE", "UNLOGGED", "WITH", "WITHOUT");
/*
- * If we have ALTER TABLE <sth> SET TABLESPACE provide a list of
- * tablespaces
+ * Complete with list of tablespaces (for SET TABLESPACE) or table AMs (for
+ * SET ACCESS METHOD).
*/
+ else if (Matches("ALTER", "TABLE", MatchAny, "SET", "ACCESS", "METHOD"))
+ COMPLETE_WITH_QUERY(Query_for_list_of_table_access_methods);
else if (Matches("ALTER", "TABLE", MatchAny, "SET", "TABLESPACE"))
COMPLETE_WITH_QUERY(Query_for_list_of_tablespaces);
/* If we have ALTER TABLE <sth> SET WITHOUT provide CLUSTER or OIDS */
diff --git a/src/include/commands/cluster.h b/src/include/commands/cluster.h
index a941f2accd..8c04466887 100644
--- a/src/include/commands/cluster.h
+++ b/src/include/commands/cluster.h
@@ -36,7 +36,7 @@ extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
extern void mark_index_clustered(Relation rel, Oid indexOid, bool is_internal);
extern Oid make_new_heap(Oid OIDOldHeap, Oid NewTableSpace, char relpersistence,
- LOCKMODE lockmode);
+ Oid relam, LOCKMODE lockmode);
extern void finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
bool is_system_catalog,
bool swap_toast_by_content,
diff --git a/src/include/commands/event_trigger.h b/src/include/commands/event_trigger.h
index c11bf2d781..e765e67fd1 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_ACCESS_METHOD 0x08
/*
* EventTriggerData is the node type that is passed as fmgr "context" info
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 236832a2ca..ce54f76610 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1868,6 +1868,7 @@ typedef enum AlterTableType
AT_SetLogged, /* SET LOGGED */
AT_SetUnLogged, /* SET UNLOGGED */
AT_DropOids, /* SET WITHOUT OIDS */
+ AT_SetAccessMethod, /* SET ACCESS METHOD */
AT_SetTableSpace, /* SET TABLESPACE */
AT_SetRelOptions, /* SET (...) -- AM specific parameters */
AT_ResetRelOptions, /* RESET (...) -- AM specific parameters */
diff --git a/src/test/regress/expected/create_am.out b/src/test/regress/expected/create_am.out
index 0dfb26c301..7ebdd5ded6 100644
--- a/src/test/regress/expected/create_am.out
+++ b/src/test/regress/expected/create_am.out
@@ -230,6 +230,22 @@ ORDER BY classid, objid, objsubid;
table tableam_parted_d_heap2
(5 rows)
+-- ALTER TABLE SET ACCESS METHOD
+CREATE TABLE heaptable USING heap AS SELECT a, repeat(a::text,9999) FROM generate_series(1,9) AS a;
+ALTER TABLE heaptable SET ACCESS METHOD heap2;
+explain (analyze, costs off, summary off, timing off) SELECT * FROM heaptable;
+ QUERY PLAN
+-----------------------------------------------
+ Seq Scan on heaptable (actual rows=9 loops=1)
+(1 row)
+
+SELECT COUNT(a), COUNT(1) FILTER(WHERE a=1) FROM heaptable;
+ count | count
+-------+-------
+ 9 | 1
+(1 row)
+
+DROP TABLE heaptable;
-- Second, create objects in the new AM by changing the default AM
BEGIN;
SET LOCAL default_table_access_method = 'heap2';
diff --git a/src/test/regress/sql/create_am.sql b/src/test/regress/sql/create_am.sql
index 9a359466ce..677a851cd3 100644
--- a/src/test/regress/sql/create_am.sql
+++ b/src/test/regress/sql/create_am.sql
@@ -161,6 +161,12 @@ WHERE pg_depend.refclassid = 'pg_am'::regclass
AND pg_am.amname = 'heap2'
ORDER BY classid, objid, objsubid;
+-- ALTER TABLE SET ACCESS METHOD
+CREATE TABLE heaptable USING heap AS SELECT a, repeat(a::text,9999) FROM generate_series(1,9) AS a;
+ALTER TABLE heaptable SET ACCESS METHOD heap2;
+explain (analyze, costs off, summary off, timing off) SELECT * FROM heaptable;
+SELECT COUNT(a), COUNT(1) FILTER(WHERE a=1) FROM heaptable;
+DROP TABLE heaptable;
-- Second, create objects in the new AM by changing the default AM
BEGIN;
--
2.17.0
--1X+6QtwRodzgDPAC
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v2-0002-Allow-specifying-acccess-method-of-partitioned-ta.patch"
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Subject: Re: [PATCH v2 1/3] ALTER TABLE SET ACCESS METHOD
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