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ALTER TABLE command to change generation expression

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This adds a new ALTER TABLE subcommand ALTER COLUMN ... SET EXPRESSION
that changes the generation expression of a generated column.

The syntax is not standard but was adapted from other SQL
implementations.

This command causes a table rewrite, using the usual ALTER TABLE
mechanisms.  The implementation is similar to and makes use of some of
the infrastructure of the SET DATA TYPE subcommand (for example,
rebuilding constraints and indexes afterwards).  The new command
requires a new pass in AlterTablePass, and the ADD COLUMN pass had to
be moved earlier so that combinations of ADD COLUMN and SET EXPRESSION
can work.

Author: Amul Sul <sulamul@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAAJ_b94yyJeGA-5M951_Lr+KfZokOp-2kXicpmEhi5FXhBeTog@mail.gmail.com
pull/152/head
Peter Eisentraut 2 years ago
parent ae69c4fcf1
commit 5d06e99a3c
8 changed files with 460 additions and 80 deletions
Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL
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  1. 12
      doc/src/sgml/ref/alter_table.sgml
  2. 235
      src/backend/commands/tablecmds.c
  3. 10
      src/backend/parser/gram.y
  4. 10
      src/bin/psql/tab-complete.c
  5. 1
      src/include/nodes/parsenodes.h
  6. 3
      src/test/modules/test_ddl_deparse/test_ddl_deparse.c
  7. 217
      src/test/regress/expected/generated.out
  8. 52
      src/test/regress/sql/generated.sql

12
doc/src/sgml/ref/alter_table.sgml
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@ -46,6 +46,7 @@ ALTER TABLE [ IF EXISTS ] <replaceable class="parameter">name</replaceable>
ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET DEFAULT <replaceable class="parameter">expression</replaceable>
ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP DEFAULT
ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> { SET | DROP } NOT NULL
ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> SET EXPRESSION AS ( <replaceable class="parameter">expression</replaceable> )
ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> DROP EXPRESSION [ IF EXISTS ]
ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> ADD GENERATED { ALWAYS | BY DEFAULT } AS IDENTITY [ ( <replaceable>sequence_options</replaceable> ) ]
ALTER [ COLUMN ] <replaceable class="parameter">column_name</replaceable> { SET GENERATED { ALWAYS | BY DEFAULT } | SET <replaceable>sequence_option</replaceable> | RESTART [ [ WITH ] <replaceable class="parameter">restart</replaceable> ] } [...]
@ -256,6 +257,17 @@ WITH ( MODULUS <replaceable class="parameter">numeric_literal</replaceable>, REM
</listitem>
</varlistentry>
<varlistentry id="sql-altertable-desc-set-expression">
<term><literal>SET EXPRESSION AS</literal></term>
<listitem>
<para>
This form replaces the expression of a generated column. Existing data
in the column is rewritten and all the future changes will apply the new
generation expression.
</para>
</listitem>
</varlistentry>
<varlistentry id="sql-altertable-desc-drop-expression">
<term><literal>DROP EXPRESSION [ IF EXISTS ]</literal></term>
<listitem>

235
src/backend/commands/tablecmds.c
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@ -147,10 +147,11 @@ typedef enum AlterTablePass
AT_PASS_UNSET = -1, /* UNSET will cause ERROR */
AT_PASS_DROP, /* DROP (all flavors) */
AT_PASS_ALTER_TYPE, /* ALTER COLUMN TYPE */
AT_PASS_ADD_COL, /* ADD COLUMN */
AT_PASS_SET_EXPRESSION, /* ALTER SET EXPRESSION */
AT_PASS_OLD_INDEX, /* re-add existing indexes */
AT_PASS_OLD_CONSTR, /* re-add existing constraints */
/* We could support a RENAME COLUMN pass here, but not currently used */
AT_PASS_ADD_COL, /* ADD COLUMN */
AT_PASS_ADD_CONSTR, /* ADD constraints (initial examination) */
AT_PASS_COL_ATTRS, /* set column attributes, eg NOT NULL */
AT_PASS_ADD_INDEXCONSTR, /* ADD index-based constraints */
@ -459,6 +460,8 @@ static ObjectAddress ATExecAddIdentity(Relation rel, const char *colName,
static ObjectAddress ATExecSetIdentity(Relation rel, const char *colName,
Node *def, LOCKMODE lockmode);
static ObjectAddress ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode);
static ObjectAddress ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
Node *newExpr, LOCKMODE lockmode);
static void ATPrepDropExpression(Relation rel, AlterTableCmd *cmd, bool recurse, bool recursing, LOCKMODE lockmode);
static ObjectAddress ATExecDropExpression(Relation rel, const char *colName, bool missing_ok, LOCKMODE lockmode);
static ObjectAddress ATExecSetStatistics(Relation rel, const char *colName, int16 colNum,
@ -561,7 +564,7 @@ static void ATPrepAlterColumnType(List **wqueue,
static bool ATColumnChangeRequiresRewrite(Node *expr, AttrNumber varattno);
static ObjectAddress ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
AlterTableCmd *cmd, LOCKMODE lockmode);
static void RememberAllDependentForRebuilding(AlteredTableInfo *tab,
static void RememberAllDependentForRebuilding(AlteredTableInfo *tab, AlterTableType subtype,
Relation rel, AttrNumber attnum, const char *colName);
static void RememberConstraintForRebuilding(Oid conoid, AlteredTableInfo *tab);
static void RememberIndexForRebuilding(Oid indoid, AlteredTableInfo *tab);
@ -4551,6 +4554,7 @@ AlterTableGetLockLevel(List *cmds)
case AT_AddIdentity:
case AT_DropIdentity:
case AT_SetIdentity:
case AT_SetExpression:
case AT_DropExpression:
case AT_SetCompression:
cmd_lockmode = AccessExclusiveLock;
@ -4852,6 +4856,11 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
pass = AT_PASS_COL_ATTRS;
break;
case AT_SetExpression: /* ALTER COLUMN SET EXPRESSION */
ATSimplePermissions(cmd->subtype, rel, ATT_TABLE | ATT_FOREIGN_TABLE);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
pass = AT_PASS_SET_EXPRESSION;
break;
case AT_DropExpression: /* ALTER COLUMN DROP EXPRESSION */
ATSimplePermissions(cmd->subtype, rel, ATT_TABLE | ATT_FOREIGN_TABLE);
ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode, context);
@ -5153,11 +5162,11 @@ ATRewriteCatalogs(List **wqueue, LOCKMODE lockmode,
lockmode, pass, context);
/*
* After the ALTER TYPE pass, do cleanup work (this is not done in
* ATExecAlterColumnType since it should be done only once if
* multiple columns of a table are altered).
* After the ALTER TYPE or SET EXPRESSION pass, do cleanup work
* (this is not done in ATExecAlterColumnType since it should be
* done only once if multiple columns of a table are altered).
*/
if (pass == AT_PASS_ALTER_TYPE)
if (pass == AT_PASS_ALTER_TYPE || pass == AT_PASS_SET_EXPRESSION)
ATPostAlterTypeCleanup(wqueue, tab, lockmode);
if (tab->rel)
@ -5236,6 +5245,9 @@ ATExecCmd(List **wqueue, AlteredTableInfo *tab,
case AT_SetAttNotNull: /* set pg_attribute.attnotnull */
address = ATExecSetAttNotNull(wqueue, rel, cmd->name, lockmode);
break;
case AT_SetExpression:
address = ATExecSetExpression(tab, rel, cmd->name, cmd->def, lockmode);
break;
case AT_DropExpression:
address = ATExecDropExpression(rel, cmd->name, cmd->missing_ok, lockmode);
break;
@ -6363,6 +6375,8 @@ alter_table_type_to_string(AlterTableType cmdtype)
return "ALTER COLUMN ... SET NOT NULL";
case AT_SetAttNotNull:
return NULL; /* not real grammar */
case AT_SetExpression:
return "ALTER COLUMN ... SET EXPRESSION";
case AT_DropExpression:
return "ALTER COLUMN ... DROP EXPRESSION";
case AT_SetStatistics:
@ -8013,10 +8027,11 @@ ATExecColumnDefault(Relation rel, const char *colName,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("column \"%s\" of relation \"%s\" is a generated column",
colName, RelationGetRelationName(rel)),
newDefault || TupleDescAttr(tupdesc, attnum - 1)->attgenerated != ATTRIBUTE_GENERATED_STORED ? 0 :
newDefault ?
/* translator: %s is an SQL ALTER command */
errhint("Use %s instead.",
"ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION")));
errhint("Use %s instead.", "ALTER TABLE ... ALTER COLUMN ... SET EXPRESSION") :
(TupleDescAttr(tupdesc, attnum - 1)->attgenerated == ATTRIBUTE_GENERATED_STORED ?
errhint("Use %s instead.", "ALTER TABLE ... ALTER COLUMN ... DROP EXPRESSION") : 0)));
/*
* Remove any old default for the column. We use RESTRICT here for
@ -8313,6 +8328,121 @@ ATExecDropIdentity(Relation rel, const char *colName, bool missing_ok, LOCKMODE
return address;
}
/*
* ALTER TABLE ALTER COLUMN SET EXPRESSION
*
* Return the address of the affected column.
*/
static ObjectAddress
ATExecSetExpression(AlteredTableInfo *tab, Relation rel, const char *colName,
Node *newExpr, LOCKMODE lockmode)
{
HeapTuple tuple;
Form_pg_attribute attTup;
AttrNumber attnum;
Oid attrdefoid;
ObjectAddress address;
Expr *defval;
NewColumnValue *newval;
RawColumnDefault *rawEnt;
tuple = SearchSysCacheAttName(RelationGetRelid(rel), colName);
if (!HeapTupleIsValid(tuple))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_COLUMN),
errmsg("column \"%s\" of relation \"%s\" does not exist",
colName, RelationGetRelationName(rel))));
attTup = (Form_pg_attribute) GETSTRUCT(tuple);
attnum = attTup->attnum;
if (attnum <= 0)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter system column \"%s\"",
colName)));
if (attTup->attgenerated != ATTRIBUTE_GENERATED_STORED)
ereport(ERROR,
(errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
errmsg("column \"%s\" of relation \"%s\" is not a generated column",
colName, RelationGetRelationName(rel))));
ReleaseSysCache(tuple);
/*
* Clear all the missing values if we're rewriting the table, since this
* renders them pointless.
*/
RelationClearMissing(rel);
/* make sure we don't conflict with later attribute modifications */
CommandCounterIncrement();
/*
* Find everything that depends on the column (constraints, indexes, etc),
* and record enough information to let us recreate the objects after
* rewrite.
*/
RememberAllDependentForRebuilding(tab, AT_SetExpression, rel, attnum, colName);
/*
* Drop the dependency records of the GENERATED expression, in particular
* its INTERNAL dependency on the column, which would otherwise cause
* dependency.c to refuse to perform the deletion.
*/
attrdefoid = GetAttrDefaultOid(RelationGetRelid(rel), attnum);
if (!OidIsValid(attrdefoid))
elog(ERROR, "could not find attrdef tuple for relation %u attnum %d",
RelationGetRelid(rel), attnum);
(void) deleteDependencyRecordsFor(AttrDefaultRelationId, attrdefoid, false);
/* Make above changes visible */
CommandCounterIncrement();
/*
* Get rid of the GENERATED expression itself. We use RESTRICT here for
* safety, but at present we do not expect anything to depend on the
* expression.
*/
RemoveAttrDefault(RelationGetRelid(rel), attnum, DROP_RESTRICT,
false, false);
/* Prepare to store the new expression, in the catalogs */
rawEnt = (RawColumnDefault *) palloc(sizeof(RawColumnDefault));
rawEnt->attnum = attnum;
rawEnt->raw_default = newExpr;
rawEnt->missingMode = false;
rawEnt->generated = ATTRIBUTE_GENERATED_STORED;
/* Store the generated expression */
AddRelationNewConstraints(rel, list_make1(rawEnt), NIL,
false, true, false, NULL);
/* Make above new expression visible */
CommandCounterIncrement();
/* Prepare for table rewrite */
defval = (Expr *) build_column_default(rel, attnum);
newval = (NewColumnValue *) palloc0(sizeof(NewColumnValue));
newval->attnum = attnum;
newval->expr = expression_planner(defval);
newval->is_generated = true;
tab->newvals = lappend(tab->newvals, newval);
tab->rewrite |= AT_REWRITE_DEFAULT_VAL;
/* Drop any pg_statistic entry for the column */
RemoveStatistics(RelationGetRelid(rel), attnum);
InvokeObjectPostAlterHook(RelationRelationId,
RelationGetRelid(rel), attnum);
ObjectAddressSubSet(address, RelationRelationId,
RelationGetRelid(rel), attnum);
return address;
}
/*
* ALTER TABLE ALTER COLUMN DROP EXPRESSION
*/
@ -13300,7 +13430,7 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
* the info before executing ALTER TYPE, though, else the deparser will
* get confused.
*/
RememberAllDependentForRebuilding(tab, rel, attnum, colName);
RememberAllDependentForRebuilding(tab, AT_AlterColumnType, rel, attnum, colName);
/*
* Now scan for dependencies of this column on other things. The only
@ -13497,18 +13627,21 @@ ATExecAlterColumnType(AlteredTableInfo *tab, Relation rel,
}
/*
* Subroutine for ATExecAlterColumnType: Find everything that depends on the
* column (constraints, indexes, etc), and record enough information to let us
* recreate the objects.
* Subroutine for ATExecAlterColumnType and ATExecSetExpression: Find everything
* that depends on the column (constraints, indexes, etc), and record enough
* information to let us recreate the objects.
*/
static void
RememberAllDependentForRebuilding(AlteredTableInfo *tab, Relation rel, AttrNumber attnum, const char *colName)
RememberAllDependentForRebuilding(AlteredTableInfo *tab, AlterTableType subtype,
Relation rel, AttrNumber attnum, const char *colName)
{
Relation depRel;
ScanKeyData key[3];
SysScanDesc scan;
HeapTuple depTup;
Assert(subtype == AT_AlterColumnType || subtype == AT_SetExpression);
depRel = table_open(DependRelationId, RowExclusiveLock);
ScanKeyInit(&key[0],
@ -13572,12 +13705,13 @@ RememberAllDependentForRebuilding(AlteredTableInfo *tab, Relation rel, AttrNumbe
case OCLASS_REWRITE:
/* XXX someday see if we can cope with revising views */
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used by a view or rule"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject, false),
colName)));
if (subtype == AT_AlterColumnType)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used by a view or rule"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject, false),
colName)));
break;
case OCLASS_TRIGGER:
@ -13591,12 +13725,13 @@ RememberAllDependentForRebuilding(AlteredTableInfo *tab, Relation rel, AttrNumbe
* significant amount of new code. Since we can't easily tell
* which case applies, we punt for both. FIXME someday.
*/
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used in a trigger definition"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject, false),
colName)));
if (subtype == AT_AlterColumnType)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used in a trigger definition"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject, false),
colName)));
break;
case OCLASS_POLICY:
@ -13609,12 +13744,13 @@ RememberAllDependentForRebuilding(AlteredTableInfo *tab, Relation rel, AttrNumbe
* easy enough to remove and recreate the policy; still, FIXME
* someday.
*/
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used in a policy definition"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject, false),
colName)));
if (subtype == AT_AlterColumnType)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used in a policy definition"),
errdetail("%s depends on column \"%s\"",
getObjectDescription(&foundObject, false),
colName)));
break;
case OCLASS_DEFAULT:
@ -13634,19 +13770,20 @@ RememberAllDependentForRebuilding(AlteredTableInfo *tab, Relation rel, AttrNumbe
/*
* This must be a reference from the expression of a
* generated column elsewhere in the same table.
* Changing the type of a column that is used by a
* generated column is not allowed by SQL standard, so
* just punt for now. It might be doable with some
* thinking and effort.
* Changing the type/generated expression of a column
* that is used by a generated column is not allowed
* by SQL standard, so just punt for now. It might be
* doable with some thinking and effort.
*/
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used by a generated column"),
errdetail("Column \"%s\" is used by generated column \"%s\".",
colName,
get_attname(col.objectId,
col.objectSubId,
false))));
if (subtype == AT_AlterColumnType)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot alter type of a column used by a generated column"),
errdetail("Column \"%s\" is used by generated column \"%s\".",
colName,
get_attname(col.objectId,
col.objectSubId,
false))));
}
break;
}
@ -13863,11 +14000,11 @@ RememberStatisticsForRebuilding(Oid stxoid, AlteredTableInfo *tab)
}
/*
* Cleanup after we've finished all the ALTER TYPE operations for a
* particular relation. We have to drop and recreate all the indexes
* and constraints that depend on the altered columns. We do the
* actual dropping here, but re-creation is managed by adding work
* queue entries to do those steps later.
* Cleanup after we've finished all the ALTER TYPE or SET EXPRESSION
* operations for a particular relation. We have to drop and recreate all the
* indexes and constraints that depend on the altered columns. We do the
* actual dropping here, but re-creation is managed by adding work queue
* entries to do those steps later.
*/
static void
ATPostAlterTypeCleanup(List **wqueue, AlteredTableInfo *tab, LOCKMODE lockmode)

10
src/backend/parser/gram.y
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@ -2417,6 +2417,16 @@ alter_table_cmd:
n->name = $3;
$$ = (Node *) n;
}
/* ALTER TABLE <name> ALTER [COLUMN] <colname> SET EXPRESSION AS <expr> */
| ALTER opt_column ColId SET EXPRESSION AS '(' a_expr ')'
{
AlterTableCmd *n = makeNode(AlterTableCmd);
n->subtype = AT_SetExpression;
n->name = $3;
n->def = $8;
$$ = (Node *) n;
}
/* ALTER TABLE <name> ALTER [COLUMN] <colname> DROP EXPRESSION */
| ALTER opt_column ColId DROP EXPRESSION
{

10
src/bin/psql/tab-complete.c
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@ -2504,7 +2504,7 @@ 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("(", "COMPRESSION", "DEFAULT", "GENERATED", "NOT NULL", "STATISTICS", "STORAGE",
COMPLETE_WITH("(", "COMPRESSION", "DEFAULT", "EXPRESSION", "GENERATED", "NOT NULL", "STATISTICS", "STORAGE",
/* a subset of ALTER SEQUENCE options */
"INCREMENT", "MINVALUE", "MAXVALUE", "START", "NO", "CACHE", "CYCLE");
/* ALTER TABLE ALTER [COLUMN] <foo> SET ( */
@ -2515,6 +2515,14 @@ psql_completion(const char *text, int start, int end)
else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "COMPRESSION") ||
Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "COMPRESSION"))
COMPLETE_WITH("DEFAULT", "PGLZ", "LZ4");
/* ALTER TABLE ALTER [COLUMN] <foo> SET EXPRESSION */
else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "EXPRESSION") ||
Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "EXPRESSION"))
COMPLETE_WITH("AS");
/* ALTER TABLE ALTER [COLUMN] <foo> SET EXPRESSION AS */
else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "EXPRESSION", "AS") ||
Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "EXPRESSION", "AS"))
COMPLETE_WITH("(");
/* ALTER TABLE ALTER [COLUMN] <foo> SET GENERATED */
else if (Matches("ALTER", "TABLE", MatchAny, "ALTER", "COLUMN", MatchAny, "SET", "GENERATED") ||
Matches("ALTER", "TABLE", MatchAny, "ALTER", MatchAny, "SET", "GENERATED"))

1
src/include/nodes/parsenodes.h
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@ -2192,6 +2192,7 @@ typedef enum AlterTableType
AT_DropNotNull, /* alter column drop not null */
AT_SetNotNull, /* alter column set not null */
AT_SetAttNotNull, /* set attnotnull w/o a constraint */
AT_SetExpression, /* alter column set expression */
AT_DropExpression, /* alter column drop expression */
AT_SetStatistics, /* alter column set statistics */
AT_SetOptions, /* alter column set ( options ) */

3
src/test/modules/test_ddl_deparse/test_ddl_deparse.c
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@ -132,6 +132,9 @@ get_altertable_subcmdinfo(PG_FUNCTION_ARGS)
case AT_SetAttNotNull:
strtype = "SET ATTNOTNULL";
break;
case AT_SetExpression:
strtype = "SET EXPRESSION";
break;
case AT_DropExpression:
strtype = "DROP EXPRESSION";
break;

217
src/test/regress/expected/generated.out
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@ -578,6 +578,9 @@ INSERT INTO gtest20 (a) VALUES (10); -- ok
INSERT INTO gtest20 (a) VALUES (30); -- violates constraint
ERROR: new row for relation "gtest20" violates check constraint "gtest20_b_check"
DETAIL: Failing row contains (30, 60).
ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100); -- violates constraint
ERROR: check constraint "gtest20_b_check" of relation "gtest20" is violated by some row
ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3); -- ok
CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
INSERT INTO gtest20a (a) VALUES (10);
INSERT INTO gtest20a (a) VALUES (30);
@ -673,6 +676,47 @@ SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
1 | 2
(1 row)
ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
ANALYZE gtest22c;
EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
QUERY PLAN
---------------------------------------------
Index Scan using gtest22c_b_idx on gtest22c
Index Cond: (b = 8)
(2 rows)
SELECT * FROM gtest22c WHERE b = 8;
a | b
---+---
2 | 8
(1 row)
EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
QUERY PLAN
------------------------------------------------
Index Scan using gtest22c_expr_idx on gtest22c
Index Cond: ((b * 3) = 12)
(2 rows)
SELECT * FROM gtest22c WHERE b * 3 = 12;
a | b
---+---
1 | 4
(1 row)
EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
QUERY PLAN
------------------------------------------------
Index Scan using gtest22c_pred_idx on gtest22c
Index Cond: (a = 1)
(2 rows)
SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
a | b
---+---
1 | 4
(1 row)
RESET enable_seqscan;
RESET enable_bitmapscan;
-- foreign keys
@ -698,6 +742,10 @@ INSERT INTO gtest23b VALUES (1); -- ok
INSERT INTO gtest23b VALUES (5); -- error
ERROR: insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
DETAIL: Key (b)=(10) is not present in table "gtest23a".
ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
ERROR: insert or update on table "gtest23b" violates foreign key constraint "gtest23b_b_fkey"
DETAIL: Key (b)=(5) is not present in table "gtest23a".
ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
DROP TABLE gtest23b;
DROP TABLE gtest23a;
CREATE TABLE gtest23p (x int, y int GENERATED ALWAYS AS (x * 2) STORED, PRIMARY KEY (y));
@ -785,30 +833,119 @@ Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
SELECT * FROM gtest_parent;
f1 | f2 | f3
------------+----+----
07-15-2016 | 1 | 2
(1 row)
INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
tableoid | f1 | f2 | f3
--------------+------------+----+----
gtest_child | 07-15-2016 | 1 | 2
gtest_child | 07-15-2016 | 2 | 4
gtest_child2 | 08-15-2016 | 3 | 66
(3 rows)
SELECT * FROM gtest_child;
f1 | f2 | f3
------------+----+----
07-15-2016 | 1 | 2
(1 row)
UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
tableoid | f1 | f2 | f3
--------------+------------+----+----
gtest_child | 07-15-2016 | 2 | 4
gtest_child2 | 08-15-2016 | 3 | 66
gtest_child3 | 09-13-2016 | 1 | 33
(3 rows)
UPDATE gtest_parent SET f1 = f1 + 60;
SELECT * FROM gtest_parent;
f1 | f2 | f3
------------+----+----
09-13-2016 | 1 | 33
(1 row)
-- alter only parent's and one child's generation expression
ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
\d gtest_parent
Partitioned table "public.gtest_parent"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+-------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 4) stored
Partition key: RANGE (f1)
Number of partitions: 3 (Use \d+ to list them.)
SELECT * FROM gtest_child3;
f1 | f2 | f3
------------+----+----
09-13-2016 | 1 | 33
(1 row)
\d gtest_child
Table "public.gtest_child"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+--------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 10) stored
Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
\d gtest_child2
Table "public.gtest_child2"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+--------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 22) stored
Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
\d gtest_child3
Table "public.gtest_child3"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+--------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 33) stored
Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
tableoid | f1 | f2 | f3
--------------+------------+----+----
gtest_child | 07-15-2016 | 2 | 20
gtest_child2 | 08-15-2016 | 3 | 66
gtest_child3 | 09-13-2016 | 1 | 33
(3 rows)
-- alter generation expression of parent and all its children altogether
ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
\d gtest_parent
Partitioned table "public.gtest_parent"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+-------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 2) stored
Partition key: RANGE (f1)
Number of partitions: 3 (Use \d+ to list them.)
\d gtest_child
Table "public.gtest_child"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+-------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 2) stored
Partition of: gtest_parent FOR VALUES FROM ('07-01-2016') TO ('08-01-2016')
\d gtest_child2
Table "public.gtest_child2"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+-------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 2) stored
Partition of: gtest_parent FOR VALUES FROM ('08-01-2016') TO ('09-01-2016')
\d gtest_child3
Table "public.gtest_child3"
Column | Type | Collation | Nullable | Default
--------+--------+-----------+----------+-------------------------------------
f1 | date | | not null |
f2 | bigint | | |
f3 | bigint | | | generated always as (f2 * 2) stored
Partition of: gtest_parent FOR VALUES FROM ('09-01-2016') TO ('10-01-2016')
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
tableoid | f1 | f2 | f3
--------------+------------+----+----
gtest_child | 07-15-2016 | 2 | 4
gtest_child2 | 08-15-2016 | 3 | 6
gtest_child3 | 09-13-2016 | 1 | 2
(3 rows)
-- we leave these tables around for purposes of testing dump/reload/upgrade
-- generated columns in partition key (not allowed)
@ -825,7 +962,7 @@ DETAIL: Column "f3" is a generated column.
-- ALTER TABLE ... ADD COLUMN
CREATE TABLE gtest25 (a int PRIMARY KEY);
INSERT INTO gtest25 VALUES (3), (4);
ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 3) STORED;
ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
SELECT * FROM gtest25 ORDER BY a;
a | b
---+----
@ -935,18 +1072,50 @@ CREATE TABLE gtest29 (
b int GENERATED ALWAYS AS (a * 2) STORED
);
INSERT INTO gtest29 (a) VALUES (3), (4);
SELECT * FROM gtest29;
a | b
---+---
3 | 6
4 | 8
(2 rows)
\d gtest29
Table "public.gtest29"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+------------------------------------
a | integer | | |
b | integer | | | generated always as (a * 2) stored
ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3); -- error
ERROR: column "a" of relation "gtest29" is not a generated column
ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION; -- error
ERROR: column "a" of relation "gtest29" is not a stored generated column
ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS; -- notice
NOTICE: column "a" of relation "gtest29" is not a stored generated column, skipping
-- Change the expression
ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
SELECT * FROM gtest29;
a | b
---+----
3 | 9
4 | 12
(2 rows)
\d gtest29
Table "public.gtest29"
Column | Type | Collation | Nullable | Default
--------+---------+-----------+----------+------------------------------------
a | integer | | |
b | integer | | | generated always as (a * 3) stored
ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
INSERT INTO gtest29 (a) VALUES (5);
INSERT INTO gtest29 (a, b) VALUES (6, 66);
SELECT * FROM gtest29;
a | b
---+----
3 | 6
4 | 8
3 | 9
4 | 12
5 |
6 | 66
(4 rows)

52
src/test/regress/sql/generated.sql
Unescape View File

@ -293,6 +293,9 @@ CREATE TABLE gtest20 (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORE
INSERT INTO gtest20 (a) VALUES (10); -- ok
INSERT INTO gtest20 (a) VALUES (30); -- violates constraint
ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 100); -- violates constraint
ALTER TABLE gtest20 ALTER COLUMN b SET EXPRESSION AS (a * 3); -- ok
CREATE TABLE gtest20a (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STORED);
INSERT INTO gtest20a (a) VALUES (10);
INSERT INTO gtest20a (a) VALUES (30);
@ -341,6 +344,15 @@ EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 6;
SELECT * FROM gtest22c WHERE b * 3 = 6;
EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
ALTER TABLE gtest22c ALTER COLUMN b SET EXPRESSION AS (a * 4);
ANALYZE gtest22c;
EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b = 8;
SELECT * FROM gtest22c WHERE b = 8;
EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE b * 3 = 12;
SELECT * FROM gtest22c WHERE b * 3 = 12;
EXPLAIN (COSTS OFF) SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
SELECT * FROM gtest22c WHERE a = 1 AND b > 0;
RESET enable_seqscan;
RESET enable_bitmapscan;
@ -356,6 +368,8 @@ CREATE TABLE gtest23b (a int PRIMARY KEY, b int GENERATED ALWAYS AS (a * 2) STOR
INSERT INTO gtest23b VALUES (1); -- ok
INSERT INTO gtest23b VALUES (5); -- error
ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 5); -- error
ALTER TABLE gtest23b ALTER COLUMN b SET EXPRESSION AS (a * 1); -- ok
DROP TABLE gtest23b;
DROP TABLE gtest23a;
@ -414,11 +428,28 @@ ALTER TABLE gtest_parent ATTACH PARTITION gtest_child3 FOR VALUES FROM ('2016-09
\d gtest_child2
\d gtest_child3
INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 1);
SELECT * FROM gtest_parent;
SELECT * FROM gtest_child;
UPDATE gtest_parent SET f1 = f1 + 60;
SELECT * FROM gtest_parent;
SELECT * FROM gtest_child3;
INSERT INTO gtest_parent (f1, f2) VALUES ('2016-07-15', 2);
INSERT INTO gtest_parent (f1, f2) VALUES ('2016-08-15', 3);
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
UPDATE gtest_parent SET f1 = f1 + 60 WHERE f2 = 1;
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
-- alter only parent's and one child's generation expression
ALTER TABLE ONLY gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 4);
ALTER TABLE gtest_child ALTER COLUMN f3 SET EXPRESSION AS (f2 * 10);
\d gtest_parent
\d gtest_child
\d gtest_child2
\d gtest_child3
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
-- alter generation expression of parent and all its children altogether
ALTER TABLE gtest_parent ALTER COLUMN f3 SET EXPRESSION AS (f2 * 2);
\d gtest_parent
\d gtest_child
\d gtest_child2
\d gtest_child3
SELECT tableoid::regclass, * FROM gtest_parent ORDER BY 1, 2, 3;
-- we leave these tables around for purposes of testing dump/reload/upgrade
-- generated columns in partition key (not allowed)
@ -428,7 +459,7 @@ CREATE TABLE gtest_part_key (f1 date NOT NULL, f2 bigint, f3 bigint GENERATED AL
-- ALTER TABLE ... ADD COLUMN
CREATE TABLE gtest25 (a int PRIMARY KEY);
INSERT INTO gtest25 VALUES (3), (4);
ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 3) STORED;
ALTER TABLE gtest25 ADD COLUMN b int GENERATED ALWAYS AS (a * 2) STORED, ALTER COLUMN b SET EXPRESSION AS (a * 3);
SELECT * FROM gtest25 ORDER BY a;
ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (b * 4) STORED; -- error
ALTER TABLE gtest25 ADD COLUMN x int GENERATED ALWAYS AS (z * 4) STORED; -- error
@ -473,8 +504,17 @@ CREATE TABLE gtest29 (
b int GENERATED ALWAYS AS (a * 2) STORED
);
INSERT INTO gtest29 (a) VALUES (3), (4);
SELECT * FROM gtest29;
\d gtest29
ALTER TABLE gtest29 ALTER COLUMN a SET EXPRESSION AS (a * 3); -- error
ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION; -- error
ALTER TABLE gtest29 ALTER COLUMN a DROP EXPRESSION IF EXISTS; -- notice
-- Change the expression
ALTER TABLE gtest29 ALTER COLUMN b SET EXPRESSION AS (a * 3);
SELECT * FROM gtest29;
\d gtest29
ALTER TABLE gtest29 ALTER COLUMN b DROP EXPRESSION;
INSERT INTO gtest29 (a) VALUES (5);
INSERT INTO gtest29 (a, b) VALUES (6, 66);

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