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Implement OR REPLACE option for CREATE AGGREGATE.

Browse Source 
Aggregates have acquired a dozen or so optional attributes in recent
years for things like parallel query and moving-aggregate mode; the
lack of an OR REPLACE option to add or change these for an existing
agg makes extension upgrades gratuitously hard. Rectify.
This commit is contained in:
Andrew Gierth 2019-03-19 01:16:50 +00:00
parent f2004f19ed
commit 01bde4fa4c
13 changed files with 235 additions and 24 deletions
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27
doc/src/sgml/ref/create_aggregate.sgml
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@ -21,7 +21,7 @@ PostgreSQL documentation
<refsynopsisdiv>
<synopsis>
CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">arg_data_type</replaceable> [ , ... ] ) (
CREATE [ OR REPLACE ] AGGREGATE <replaceable class="parameter">name</replaceable> ( [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">arg_data_type</replaceable> [ , ... ] ) (
SFUNC = <replaceable class="parameter">sfunc</replaceable>,
STYPE = <replaceable class="parameter">state_data_type</replaceable>
[ , SSPACE = <replaceable class="parameter">state_data_size</replaceable> ]
@ -44,7 +44,7 @@ CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ <replacea
[ , PARALLEL = { SAFE | RESTRICTED | UNSAFE } ]
)
CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">arg_data_type</replaceable> [ , ... ] ]
CREATE [ OR REPLACE ] AGGREGATE <replaceable class="parameter">name</replaceable> ( [ [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">arg_data_type</replaceable> [ , ... ] ]
ORDER BY [ <replaceable class="parameter">argmode</replaceable> ] [ <replaceable class="parameter">argname</replaceable> ] <replaceable class="parameter">arg_data_type</replaceable> [ , ... ] ) (
SFUNC = <replaceable class="parameter">sfunc</replaceable>,
STYPE = <replaceable class="parameter">state_data_type</replaceable>
@ -59,7 +59,7 @@ CREATE AGGREGATE <replaceable class="parameter">name</replaceable> ( [ [ <replac
<phrase>or the old syntax</phrase>
CREATE AGGREGATE <replaceable class="parameter">name</replaceable> (
CREATE [ OR REPLACE ] AGGREGATE <replaceable class="parameter">name</replaceable> (
BASETYPE = <replaceable class="parameter">base_type</replaceable>,
SFUNC = <replaceable class="parameter">sfunc</replaceable>,
STYPE = <replaceable class="parameter">state_data_type</replaceable>
@ -88,12 +88,21 @@ CREATE AGGREGATE <replaceable class="parameter">name</replaceable> (
<title>Description</title>
<para>
<command>CREATE AGGREGATE</command> defines a new aggregate
function. Some basic and commonly-used aggregate functions are
included with the distribution; they are documented in <xref
linkend="functions-aggregate"/>. If one defines new types or needs
an aggregate function not already provided, then <command>CREATE
AGGREGATE</command> can be used to provide the desired features.
<command>CREATE AGGREGATE</command> defines a new aggregate function.
<command>CREATE OR REPLACE AGGREGATE</command> will either define a new
aggregate function or replace an existing definition. Some basic and
commonly-used aggregate functions are included with the distribution; they
are documented in <xref linkend="functions-aggregate"/>. If one defines new
types or needs an aggregate function not already provided, then
<command>CREATE AGGREGATE</command> can be used to provide the desired
features.
</para>
<para>
When replacing an existing definition, the argument types, result type,
and number of direct arguments may not be changed. Also, the new definition
must be of the same kind (ordinary aggregate, ordered-set aggregate, or
hypothetical-set aggregate) as the old one.
</para>
<para>

57
src/backend/catalog/pg_aggregate.c
View File

@ -45,6 +45,7 @@ static Oid lookup_agg_function(List *fnName, int nargs, Oid *input_types,
ObjectAddress
AggregateCreate(const char *aggName,
Oid aggNamespace,
bool replace,
char aggKind,
int numArgs,
int numDirectArgs,
@ -77,8 +78,10 @@ AggregateCreate(const char *aggName,
{
Relation aggdesc;
HeapTuple tup;
HeapTuple oldtup;
bool nulls[Natts_pg_aggregate];
Datum values[Natts_pg_aggregate];
bool replaces[Natts_pg_aggregate];
Form_pg_proc proc;
Oid transfn;
Oid finalfn = InvalidOid; /* can be omitted */
@ -609,7 +612,7 @@ AggregateCreate(const char *aggName,
myself = ProcedureCreate(aggName,
aggNamespace,
false, /* no replacement */
replace, /* maybe replacement */
false, /* doesn't return a set */
finaltype, /* returnType */
GetUserId(), /* proowner */
@ -648,6 +651,7 @@ AggregateCreate(const char *aggName,
{
nulls[i] = false;
values[i] = (Datum) NULL;
replaces[i] = true;
}
values[Anum_pg_aggregate_aggfnoid - 1] = ObjectIdGetDatum(procOid);
values[Anum_pg_aggregate_aggkind - 1] = CharGetDatum(aggKind);
@ -678,8 +682,51 @@ AggregateCreate(const char *aggName,
else
nulls[Anum_pg_aggregate_aggminitval - 1] = true;
tup = heap_form_tuple(tupDesc, values, nulls);
CatalogTupleInsert(aggdesc, tup);
if (replace)
oldtup = SearchSysCache1(AGGFNOID, ObjectIdGetDatum(procOid));
else
oldtup = NULL;
if (HeapTupleIsValid(oldtup))
{
Form_pg_aggregate oldagg = (Form_pg_aggregate) GETSTRUCT(oldtup);
/*
* If we're replacing an existing entry, we need to validate that
* we're not changing anything that would break callers.
* Specifically we must not change aggkind or aggnumdirectargs,
* which affect how an aggregate call is treated in parse
* analysis.
*/
if (aggKind != oldagg->aggkind)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("cannot change routine kind"),
(oldagg->aggkind == AGGKIND_NORMAL ?
errdetail("\"%s\" is an ordinary aggregate function.", aggName) :
oldagg->aggkind == AGGKIND_ORDERED_SET ?
errdetail("\"%s\" is an ordered-set aggregate.", aggName) :
oldagg->aggkind == AGGKIND_HYPOTHETICAL ?
errdetail("\"%s\" is a hypothetical-set aggregate.", aggName) :
0)));
if (numDirectArgs != oldagg->aggnumdirectargs)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("cannot change number of direct args of an aggregate function")));
replaces[Anum_pg_aggregate_aggfnoid - 1] = false;
replaces[Anum_pg_aggregate_aggkind - 1] = false;
replaces[Anum_pg_aggregate_aggnumdirectargs - 1] = false;
tup = heap_modify_tuple(oldtup, tupDesc, values, nulls, replaces);
CatalogTupleUpdate(aggdesc, &tup->t_self, tup);
ReleaseSysCache(oldtup);
}
else
{
tup = heap_form_tuple(tupDesc, values, nulls);
CatalogTupleInsert(aggdesc, tup);
}
table_close(aggdesc, RowExclusiveLock);
@ -688,6 +735,10 @@ AggregateCreate(const char *aggName,
* made by ProcedureCreate). Note: we don't need an explicit dependency
* on aggTransType since we depend on it indirectly through transfn.
* Likewise for aggmTransType using the mtransfunc, if it exists.
*
* If we're replacing an existing definition, ProcedureCreate deleted all
* our existing dependencies, so we have to do the same things here either
* way.
*/
/* Depends on transition function */

6
src/backend/catalog/pg_proc.c
View File

@ -404,7 +404,9 @@ ProcedureCreate(const char *procedureName,
errdetail("\"%s\" is a window function.", procedureName) :
0)));
dropcmd = (prokind == PROKIND_PROCEDURE ? "DROP PROCEDURE" : "DROP FUNCTION");
dropcmd = (prokind == PROKIND_PROCEDURE ? "DROP PROCEDURE" :
prokind == PROKIND_AGGREGATE ? "DROP AGGREGATE" :
"DROP FUNCTION");
/*
* Not okay to change the return type of the existing proc, since
@ -421,7 +423,7 @@ ProcedureCreate(const char *procedureName,
prokind == PROKIND_PROCEDURE
? errmsg("cannot change whether a procedure has output parameters")
: errmsg("cannot change return type of existing function"),
/* translator: first %s is DROP FUNCTION or DROP PROCEDURE */
/* translator: first %s is DROP FUNCTION, DROP PROCEDURE or DROP AGGREGATE */
errhint("Use %s %s first.",
dropcmd,
format_procedure(oldproc->oid))));

8
src/backend/commands/aggregatecmds.c
View File

@ -54,7 +54,12 @@ static char extractModify(DefElem *defel);
* "parameters" is a list of DefElem representing the agg's definition clauses.
*/
ObjectAddress
DefineAggregate(ParseState *pstate, List *name, List *args, bool oldstyle, List *parameters)
DefineAggregate(ParseState *pstate,
List *name,
List *args,
bool oldstyle,
List *parameters,
bool replace)
{
char *aggName;
Oid aggNamespace;
@ -436,6 +441,7 @@ DefineAggregate(ParseState *pstate, List *name, List *args, bool oldstyle, List
*/
return AggregateCreate(aggName, /* aggregate name */
aggNamespace, /* namespace */
replace,
aggKind,
numArgs,
numDirectArgs,

1
src/backend/nodes/copyfuncs.c
View File

@ -3372,6 +3372,7 @@ _copyDefineStmt(const DefineStmt *from)
COPY_NODE_FIELD(args);
COPY_NODE_FIELD(definition);
COPY_SCALAR_FIELD(if_not_exists);
COPY_SCALAR_FIELD(replace);
return newnode;
}

1
src/backend/nodes/equalfuncs.c
View File

@ -1265,6 +1265,7 @@ _equalDefineStmt(const DefineStmt *a, const DefineStmt *b)
COMPARE_NODE_FIELD(args);
COMPARE_NODE_FIELD(definition);
COMPARE_SCALAR_FIELD(if_not_exists);
COMPARE_SCALAR_FIELD(replace);
return true;
}

16
src/backend/parser/gram.y
View File

@ -5618,25 +5618,27 @@ CreateAssertionStmt:
*****************************************************************************/
DefineStmt:
CREATE AGGREGATE func_name aggr_args definition
CREATE opt_or_replace AGGREGATE func_name aggr_args definition
{
DefineStmt *n = makeNode(DefineStmt);
n->kind = OBJECT_AGGREGATE;
n->oldstyle = false;
n->defnames = $3;
n->args = $4;
n->definition = $5;
n->replace = $2;
n->defnames = $4;
n->args = $5;
n->definition = $6;
$$ = (Node *)n;
}
| CREATE AGGREGATE func_name old_aggr_definition
| CREATE opt_or_replace AGGREGATE func_name old_aggr_definition
{
/* old-style (pre-8.2) syntax for CREATE AGGREGATE */
DefineStmt *n = makeNode(DefineStmt);
n->kind = OBJECT_AGGREGATE;
n->oldstyle = true;
n->defnames = $3;
n->replace = $2;
n->defnames = $4;
n->args = NIL;
n->definition = $4;
n->definition = $5;
$$ = (Node *)n;
}
| CREATE OPERATOR any_operator definition

3
src/backend/tcop/utility.c
View File

@ -1237,7 +1237,8 @@ ProcessUtilitySlow(ParseState *pstate,
address =
DefineAggregate(pstate, stmt->defnames, stmt->args,
stmt->oldstyle,
stmt->definition);
stmt->definition,
stmt->replace);
break;
case OBJECT_OPERATOR:
Assert(stmt->args == NIL);

1
src/include/catalog/pg_aggregate.h
View File

@ -142,6 +142,7 @@ typedef FormData_pg_aggregate *Form_pg_aggregate;
extern ObjectAddress AggregateCreate(const char *aggName,
Oid aggNamespace,
bool replace,
char aggKind,
int numArgs,
int numDirectArgs,

2
src/include/commands/defrem.h
View File

@ -94,7 +94,7 @@ extern void UpdateStatisticsForTypeChange(Oid statsOid,
/* commands/aggregatecmds.c */
extern ObjectAddress DefineAggregate(ParseState *pstate, List *name, List *args, bool oldstyle,
List *parameters);
List *parameters, bool replace);
/* commands/opclasscmds.c */
extern ObjectAddress DefineOpClass(CreateOpClassStmt *stmt);

1
src/include/nodes/parsenodes.h
View File

@ -2532,6 +2532,7 @@ typedef struct DefineStmt
List *args; /* a list of TypeName (if needed) */
List *definition; /* a list of DefElem */
bool if_not_exists; /* just do nothing if it already exists? */
bool replace; /* replace if already exists? */
} DefineStmt;
/* ----------------------

71
src/test/regress/expected/create_aggregate.out
View File

@ -160,6 +160,77 @@ WHERE aggfnoid = 'myavg'::REGPROC;
myavg | numeric_avg_accum | numeric_avg_combine | internal | numeric_avg_serialize | numeric_avg_deserialize | s
(1 row)
DROP AGGREGATE myavg (numeric);
-- create or replace aggregate
CREATE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
finalfunc = numeric_avg
);
CREATE OR REPLACE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
finalfunc = numeric_avg,
serialfunc = numeric_avg_serialize,
deserialfunc = numeric_avg_deserialize,
combinefunc = numeric_avg_combine,
finalfunc_modify = shareable -- just to test a non-default setting
);
-- Ensure all these functions made it into the catalog again
SELECT aggfnoid, aggtransfn, aggcombinefn, aggtranstype::regtype,
aggserialfn, aggdeserialfn, aggfinalmodify
FROM pg_aggregate
WHERE aggfnoid = 'myavg'::REGPROC;
aggfnoid | aggtransfn | aggcombinefn | aggtranstype | aggserialfn | aggdeserialfn | aggfinalmodify
----------+-------------------+---------------------+--------------+-----------------------+-------------------------+----------------
myavg | numeric_avg_accum | numeric_avg_combine | internal | numeric_avg_serialize | numeric_avg_deserialize | s
(1 row)
-- can change stype:
CREATE OR REPLACE AGGREGATE myavg (numeric)
(
stype = numeric,
sfunc = numeric_add
);
SELECT aggfnoid, aggtransfn, aggcombinefn, aggtranstype::regtype,
aggserialfn, aggdeserialfn, aggfinalmodify
FROM pg_aggregate
WHERE aggfnoid = 'myavg'::REGPROC;
aggfnoid | aggtransfn | aggcombinefn | aggtranstype | aggserialfn | aggdeserialfn | aggfinalmodify
----------+-------------+--------------+--------------+-------------+---------------+----------------
myavg | numeric_add | - | numeric | - | - | r
(1 row)
-- can't change return type:
CREATE OR REPLACE AGGREGATE myavg (numeric)
(
stype = numeric,
sfunc = numeric_add,
finalfunc = numeric_out
);
ERROR: cannot change return type of existing function
HINT: Use DROP AGGREGATE myavg(numeric) first.
-- can't change to a different kind:
CREATE OR REPLACE AGGREGATE myavg (order by numeric)
(
stype = numeric,
sfunc = numeric_add
);
ERROR: cannot change routine kind
DETAIL: "myavg" is an ordinary aggregate function.
-- can't change plain function to aggregate:
create function sum4(int8,int8,int8,int8) returns int8 as
'select $1 + $2 + $3 + $4' language sql strict immutable;
CREATE OR REPLACE AGGREGATE sum3 (int8,int8,int8)
(
stype = int8,
sfunc = sum4
);
ERROR: cannot change routine kind
DETAIL: "sum3" is a function.
drop function sum4(int8,int8,int8,int8);
DROP AGGREGATE myavg (numeric);
-- invalid: bad parallel-safety marking
CREATE AGGREGATE mysum (int)

65
src/test/regress/sql/create_aggregate.sql
View File

@ -174,6 +174,71 @@ WHERE aggfnoid = 'myavg'::REGPROC;
DROP AGGREGATE myavg (numeric);
-- create or replace aggregate
CREATE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
finalfunc = numeric_avg
);
CREATE OR REPLACE AGGREGATE myavg (numeric)
(
stype = internal,
sfunc = numeric_avg_accum,
finalfunc = numeric_avg,
serialfunc = numeric_avg_serialize,
deserialfunc = numeric_avg_deserialize,
combinefunc = numeric_avg_combine,
finalfunc_modify = shareable -- just to test a non-default setting
);
-- Ensure all these functions made it into the catalog again
SELECT aggfnoid, aggtransfn, aggcombinefn, aggtranstype::regtype,
aggserialfn, aggdeserialfn, aggfinalmodify
FROM pg_aggregate
WHERE aggfnoid = 'myavg'::REGPROC;
-- can change stype:
CREATE OR REPLACE AGGREGATE myavg (numeric)
(
stype = numeric,
sfunc = numeric_add
);
SELECT aggfnoid, aggtransfn, aggcombinefn, aggtranstype::regtype,
aggserialfn, aggdeserialfn, aggfinalmodify
FROM pg_aggregate
WHERE aggfnoid = 'myavg'::REGPROC;
-- can't change return type:
CREATE OR REPLACE AGGREGATE myavg (numeric)
(
stype = numeric,
sfunc = numeric_add,
finalfunc = numeric_out
);
-- can't change to a different kind:
CREATE OR REPLACE AGGREGATE myavg (order by numeric)
(
stype = numeric,
sfunc = numeric_add
);
-- can't change plain function to aggregate:
create function sum4(int8,int8,int8,int8) returns int8 as
'select $1 + $2 + $3 + $4' language sql strict immutable;
CREATE OR REPLACE AGGREGATE sum3 (int8,int8,int8)
(
stype = int8,
sfunc = sum4
);
drop function sum4(int8,int8,int8,int8);
DROP AGGREGATE myavg (numeric);
-- invalid: bad parallel-safety marking
CREATE AGGREGATE mysum (int)
(