postgresql/src/backend/commands/aggregatecmds.c

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/*-------------------------------------------------------------------------
*
* aggregatecmds.c
*
* Routines for aggregate-manipulation commands
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
2010-09-20 22:08:53 +02:00
* src/backend/commands/aggregatecmds.c
*
* DESCRIPTION
* The "DefineFoo" routines take the parse tree and pick out the
* appropriate arguments/flags, passing the results to the
* corresponding "FooDefine" routines (in src/catalog) that do
* the actual catalog-munging. These routines also verify permission
* of the user to execute the command.
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/dependency.h"
#include "catalog/pg_aggregate.h"
#include "catalog/pg_namespace.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "commands/alter.h"
#include "commands/defrem.h"
#include "miscadmin.h"
#include "parser/parse_func.h"
#include "parser/parse_type.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
static char extractModify(DefElem *defel);
/*
* DefineAggregate
*
* "oldstyle" signals the old (pre-8.2) style where the aggregate input type
* is specified by a BASETYPE element in the parameters. Otherwise,
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
* "args" is a pair, whose first element is a list of FunctionParameter structs
* defining the agg's arguments (both direct and aggregated), and whose second
* element is an Integer node with the number of direct args, or -1 if this
* isn't an ordered-set aggregate.
* "parameters" is a list of DefElem representing the agg's definition clauses.
*/
ObjectAddress
DefineAggregate(ParseState *pstate,
List *name,
List *args,
bool oldstyle,
List *parameters,
bool replace)
{
char *aggName;
Oid aggNamespace;
AclResult aclresult;
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
char aggKind = AGGKIND_NORMAL;
List *transfuncName = NIL;
List *finalfuncName = NIL;
List *combinefuncName = NIL;
List *serialfuncName = NIL;
List *deserialfuncName = NIL;
List *mtransfuncName = NIL;
List *minvtransfuncName = NIL;
List *mfinalfuncName = NIL;
Allow polymorphic aggregates to have non-polymorphic state data types. Before 9.4, such an aggregate couldn't be declared, because its final function would have to have polymorphic result type but no polymorphic argument, which CREATE FUNCTION would quite properly reject. The ordered-set-aggregate patch found a workaround: allow the final function to be declared as accepting additional dummy arguments that have types matching the aggregate's regular input arguments. However, we failed to notice that this problem applies just as much to regular aggregates, despite the fact that we had a built-in regular aggregate array_agg() that was known to be undeclarable in SQL because its final function had an illegal signature. So what we should have done, and what this patch does, is to decouple the extra-dummy-arguments behavior from ordered-set aggregates and make it generally available for all aggregate declarations. We have to put this into 9.4 rather than waiting till later because it slightly alters the rules for declaring ordered-set aggregates. The patch turned out a bit bigger than I'd hoped because it proved necessary to record the extra-arguments option in a new pg_aggregate column. I'd thought we could just look at the final function's pronargs at runtime, but that didn't work well for variadic final functions. It's probably just as well though, because it simplifies life for pg_dump to record the option explicitly. While at it, fix array_agg() to have a valid final-function signature, and add an opr_sanity test to notice future deviations from polymorphic consistency. I also marked the percentile_cont() aggregates as not needing extra arguments, since they don't.
2014-04-24 01:17:31 +02:00
bool finalfuncExtraArgs = false;
bool mfinalfuncExtraArgs = false;
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
char finalfuncModify = 0;
char mfinalfuncModify = 0;
List *sortoperatorName = NIL;
TypeName *baseType = NULL;
TypeName *transType = NULL;
TypeName *mtransType = NULL;
int32 transSpace = 0;
int32 mtransSpace = 0;
char *initval = NULL;
char *minitval = NULL;
char *parallel = NULL;
int numArgs;
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
int numDirectArgs = 0;
oidvector *parameterTypes;
ArrayType *allParameterTypes;
ArrayType *parameterModes;
ArrayType *parameterNames;
List *parameterDefaults;
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
Oid variadicArgType;
Oid transTypeId;
Oid mtransTypeId = InvalidOid;
char transTypeType;
char mtransTypeType = 0;
char proparallel = PROPARALLEL_UNSAFE;
ListCell *pl;
/* Convert list of names to a name and namespace */
aggNamespace = QualifiedNameGetCreationNamespace(name, &aggName);
/* Check we have creation rights in target namespace */
aclresult = object_aclcheck(NamespaceRelationId, aggNamespace, GetUserId(), ACL_CREATE);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, OBJECT_SCHEMA,
get_namespace_name(aggNamespace));
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
/* Deconstruct the output of the aggr_args grammar production */
if (!oldstyle)
{
Assert(list_length(args) == 2);
numDirectArgs = intVal(lsecond(args));
if (numDirectArgs >= 0)
aggKind = AGGKIND_ORDERED_SET;
else
numDirectArgs = 0;
args = linitial_node(List, args);
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
}
/* Examine aggregate's definition clauses */
foreach(pl, parameters)
{
DefElem *defel = lfirst_node(DefElem, pl);
/*
* sfunc1, stype1, and initcond1 are accepted as obsolete spellings
* for sfunc, stype, initcond.
*/
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
if (strcmp(defel->defname, "sfunc") == 0)
transfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "sfunc1") == 0)
transfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "finalfunc") == 0)
finalfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "combinefunc") == 0)
combinefuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "serialfunc") == 0)
serialfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "deserialfunc") == 0)
deserialfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "msfunc") == 0)
mtransfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "minvfunc") == 0)
minvtransfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "mfinalfunc") == 0)
mfinalfuncName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "finalfunc_extra") == 0)
Allow polymorphic aggregates to have non-polymorphic state data types. Before 9.4, such an aggregate couldn't be declared, because its final function would have to have polymorphic result type but no polymorphic argument, which CREATE FUNCTION would quite properly reject. The ordered-set-aggregate patch found a workaround: allow the final function to be declared as accepting additional dummy arguments that have types matching the aggregate's regular input arguments. However, we failed to notice that this problem applies just as much to regular aggregates, despite the fact that we had a built-in regular aggregate array_agg() that was known to be undeclarable in SQL because its final function had an illegal signature. So what we should have done, and what this patch does, is to decouple the extra-dummy-arguments behavior from ordered-set aggregates and make it generally available for all aggregate declarations. We have to put this into 9.4 rather than waiting till later because it slightly alters the rules for declaring ordered-set aggregates. The patch turned out a bit bigger than I'd hoped because it proved necessary to record the extra-arguments option in a new pg_aggregate column. I'd thought we could just look at the final function's pronargs at runtime, but that didn't work well for variadic final functions. It's probably just as well though, because it simplifies life for pg_dump to record the option explicitly. While at it, fix array_agg() to have a valid final-function signature, and add an opr_sanity test to notice future deviations from polymorphic consistency. I also marked the percentile_cont() aggregates as not needing extra arguments, since they don't.
2014-04-24 01:17:31 +02:00
finalfuncExtraArgs = defGetBoolean(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "mfinalfunc_extra") == 0)
Allow polymorphic aggregates to have non-polymorphic state data types. Before 9.4, such an aggregate couldn't be declared, because its final function would have to have polymorphic result type but no polymorphic argument, which CREATE FUNCTION would quite properly reject. The ordered-set-aggregate patch found a workaround: allow the final function to be declared as accepting additional dummy arguments that have types matching the aggregate's regular input arguments. However, we failed to notice that this problem applies just as much to regular aggregates, despite the fact that we had a built-in regular aggregate array_agg() that was known to be undeclarable in SQL because its final function had an illegal signature. So what we should have done, and what this patch does, is to decouple the extra-dummy-arguments behavior from ordered-set aggregates and make it generally available for all aggregate declarations. We have to put this into 9.4 rather than waiting till later because it slightly alters the rules for declaring ordered-set aggregates. The patch turned out a bit bigger than I'd hoped because it proved necessary to record the extra-arguments option in a new pg_aggregate column. I'd thought we could just look at the final function's pronargs at runtime, but that didn't work well for variadic final functions. It's probably just as well though, because it simplifies life for pg_dump to record the option explicitly. While at it, fix array_agg() to have a valid final-function signature, and add an opr_sanity test to notice future deviations from polymorphic consistency. I also marked the percentile_cont() aggregates as not needing extra arguments, since they don't.
2014-04-24 01:17:31 +02:00
mfinalfuncExtraArgs = defGetBoolean(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "finalfunc_modify") == 0)
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
finalfuncModify = extractModify(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "mfinalfunc_modify") == 0)
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
mfinalfuncModify = extractModify(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "sortop") == 0)
sortoperatorName = defGetQualifiedName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "basetype") == 0)
baseType = defGetTypeName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "hypothetical") == 0)
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
{
if (defGetBoolean(defel))
{
if (aggKind == AGGKIND_NORMAL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("only ordered-set aggregates can be hypothetical")));
aggKind = AGGKIND_HYPOTHETICAL;
}
}
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "stype") == 0)
transType = defGetTypeName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "stype1") == 0)
transType = defGetTypeName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "sspace") == 0)
transSpace = defGetInt32(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "mstype") == 0)
mtransType = defGetTypeName(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "msspace") == 0)
mtransSpace = defGetInt32(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "initcond") == 0)
initval = defGetString(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "initcond1") == 0)
initval = defGetString(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "minitcond") == 0)
minitval = defGetString(defel);
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(defel->defname, "parallel") == 0)
parallel = defGetString(defel);
else
ereport(WARNING,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("aggregate attribute \"%s\" not recognized",
defel->defname)));
}
/*
* make sure we have our required definitions
*/
if (transType == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate stype must be specified")));
if (transfuncName == NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate sfunc must be specified")));
/*
* if mtransType is given, mtransfuncName and minvtransfuncName must be as
* well; if not, then none of the moving-aggregate options should have
* been given.
*/
if (mtransType != NULL)
{
if (mtransfuncName == NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate msfunc must be specified when mstype is specified")));
if (minvtransfuncName == NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate minvfunc must be specified when mstype is specified")));
}
else
{
if (mtransfuncName != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate msfunc must not be specified without mstype")));
if (minvtransfuncName != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate minvfunc must not be specified without mstype")));
if (mfinalfuncName != NIL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate mfinalfunc must not be specified without mstype")));
if (mtransSpace != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate msspace must not be specified without mstype")));
if (minitval != NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate minitcond must not be specified without mstype")));
}
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
/*
* Default values for modify flags can only be determined once we know the
* aggKind.
*/
if (finalfuncModify == 0)
finalfuncModify = (aggKind == AGGKIND_NORMAL) ? AGGMODIFY_READ_ONLY : AGGMODIFY_READ_WRITE;
if (mfinalfuncModify == 0)
mfinalfuncModify = (aggKind == AGGKIND_NORMAL) ? AGGMODIFY_READ_ONLY : AGGMODIFY_READ_WRITE;
/*
* look up the aggregate's input datatype(s).
*/
if (oldstyle)
{
/*
* Old style: use basetype parameter. This supports aggregates of
* zero or one input, with input type ANY meaning zero inputs.
*
* Historically we allowed the command to look like basetype = 'ANY'
* so we must do a case-insensitive comparison for the name ANY. Ugh.
*/
Oid aggArgTypes[1];
if (baseType == NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate input type must be specified")));
if (pg_strcasecmp(TypeNameToString(baseType), "ANY") == 0)
{
numArgs = 0;
aggArgTypes[0] = InvalidOid;
}
else
{
numArgs = 1;
aggArgTypes[0] = typenameTypeId(NULL, baseType);
}
parameterTypes = buildoidvector(aggArgTypes, numArgs);
allParameterTypes = NULL;
parameterModes = NULL;
parameterNames = NULL;
parameterDefaults = NIL;
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
variadicArgType = InvalidOid;
}
else
{
/*
* New style: args is a list of FunctionParameters (possibly zero of
* 'em). We share functioncmds.c's code for processing them.
*/
Oid requiredResultType;
if (baseType != NULL)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("basetype is redundant with aggregate input type specification")));
numArgs = list_length(args);
interpret_function_parameter_list(pstate,
args,
InvalidOid,
OBJECT_AGGREGATE,
&parameterTypes,
SQL-standard function body This adds support for writing CREATE FUNCTION and CREATE PROCEDURE statements for language SQL with a function body that conforms to the SQL standard and is portable to other implementations. Instead of the PostgreSQL-specific AS $$ string literal $$ syntax, this allows writing out the SQL statements making up the body unquoted, either as a single statement: CREATE FUNCTION add(a integer, b integer) RETURNS integer LANGUAGE SQL RETURN a + b; or as a block CREATE PROCEDURE insert_data(a integer, b integer) LANGUAGE SQL BEGIN ATOMIC INSERT INTO tbl VALUES (a); INSERT INTO tbl VALUES (b); END; The function body is parsed at function definition time and stored as expression nodes in a new pg_proc column prosqlbody. So at run time, no further parsing is required. However, this form does not support polymorphic arguments, because there is no more parse analysis done at call time. Dependencies between the function and the objects it uses are fully tracked. A new RETURN statement is introduced. This can only be used inside function bodies. Internally, it is treated much like a SELECT statement. psql needs some new intelligence to keep track of function body boundaries so that it doesn't send off statements when it sees semicolons that are inside a function body. Tested-by: Jaime Casanova <jcasanov@systemguards.com.ec> Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/1c11f1eb-f00c-43b7-799d-2d44132c02d7@2ndquadrant.com
2021-04-07 21:30:08 +02:00
NULL,
&allParameterTypes,
&parameterModes,
&parameterNames,
SQL-standard function body This adds support for writing CREATE FUNCTION and CREATE PROCEDURE statements for language SQL with a function body that conforms to the SQL standard and is portable to other implementations. Instead of the PostgreSQL-specific AS $$ string literal $$ syntax, this allows writing out the SQL statements making up the body unquoted, either as a single statement: CREATE FUNCTION add(a integer, b integer) RETURNS integer LANGUAGE SQL RETURN a + b; or as a block CREATE PROCEDURE insert_data(a integer, b integer) LANGUAGE SQL BEGIN ATOMIC INSERT INTO tbl VALUES (a); INSERT INTO tbl VALUES (b); END; The function body is parsed at function definition time and stored as expression nodes in a new pg_proc column prosqlbody. So at run time, no further parsing is required. However, this form does not support polymorphic arguments, because there is no more parse analysis done at call time. Dependencies between the function and the objects it uses are fully tracked. A new RETURN statement is introduced. This can only be used inside function bodies. Internally, it is treated much like a SELECT statement. psql needs some new intelligence to keep track of function body boundaries so that it doesn't send off statements when it sees semicolons that are inside a function body. Tested-by: Jaime Casanova <jcasanov@systemguards.com.ec> Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/1c11f1eb-f00c-43b7-799d-2d44132c02d7@2ndquadrant.com
2021-04-07 21:30:08 +02:00
NULL,
&parameterDefaults,
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
&variadicArgType,
&requiredResultType);
/* Parameter defaults are not currently allowed by the grammar */
Assert(parameterDefaults == NIL);
/* There shouldn't have been any OUT parameters, either */
Assert(requiredResultType == InvalidOid);
}
/*
* look up the aggregate's transtype.
*
* transtype can't be a pseudo-type, since we need to be able to store
* values of the transtype. However, we can allow polymorphic transtype
* in some cases (AggregateCreate will check). Also, we allow "internal"
* for functions that want to pass pointers to private data structures;
* but allow that only to superusers, since you could crash the system (or
* worse) by connecting up incompatible internal-using functions in an
* aggregate.
*/
transTypeId = typenameTypeId(NULL, transType);
transTypeType = get_typtype(transTypeId);
if (transTypeType == TYPTYPE_PSEUDO &&
!IsPolymorphicType(transTypeId))
{
if (transTypeId == INTERNALOID && superuser())
/* okay */ ;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate transition data type cannot be %s",
format_type_be(transTypeId))));
}
Fix type-safety problem with parallel aggregate serial/deserialization. The original specification for this called for the deserialization function to have signature "deserialize(serialtype) returns transtype", which is a security violation if transtype is INTERNAL (which it always would be in practice) and serialtype is not (which ditto). The patch blithely overrode the opr_sanity check for that, which was sloppy-enough work in itself, but the indisputable reason this cannot be allowed to stand is that CREATE FUNCTION will reject such a signature and thus it'd be impossible for extensions to create parallelizable aggregates. The minimum fix to make the signature type-safe is to add a second, dummy argument of type INTERNAL. But to lock it down a bit more and make misuse of INTERNAL-accepting functions less likely, let's get rid of the ability to specify a "serialtype" for an aggregate and just say that the only useful serialtype is BYTEA --- which, in practice, is the only interesting value anyway, due to the usefulness of the send/recv infrastructure for this purpose. That means we only have to allow "serialize(internal) returns bytea" and "deserialize(bytea, internal) returns internal" as the signatures for these support functions. In passing fix bogus signature of int4_avg_combine, which I found thanks to adding an opr_sanity check on combinefunc signatures. catversion bump due to removing pg_aggregate.aggserialtype and adjusting signatures of assorted built-in functions. David Rowley and Tom Lane Discussion: <27247.1466185504@sss.pgh.pa.us>
2016-06-22 22:52:41 +02:00
if (serialfuncName && deserialfuncName)
{
/*
Fix type-safety problem with parallel aggregate serial/deserialization. The original specification for this called for the deserialization function to have signature "deserialize(serialtype) returns transtype", which is a security violation if transtype is INTERNAL (which it always would be in practice) and serialtype is not (which ditto). The patch blithely overrode the opr_sanity check for that, which was sloppy-enough work in itself, but the indisputable reason this cannot be allowed to stand is that CREATE FUNCTION will reject such a signature and thus it'd be impossible for extensions to create parallelizable aggregates. The minimum fix to make the signature type-safe is to add a second, dummy argument of type INTERNAL. But to lock it down a bit more and make misuse of INTERNAL-accepting functions less likely, let's get rid of the ability to specify a "serialtype" for an aggregate and just say that the only useful serialtype is BYTEA --- which, in practice, is the only interesting value anyway, due to the usefulness of the send/recv infrastructure for this purpose. That means we only have to allow "serialize(internal) returns bytea" and "deserialize(bytea, internal) returns internal" as the signatures for these support functions. In passing fix bogus signature of int4_avg_combine, which I found thanks to adding an opr_sanity check on combinefunc signatures. catversion bump due to removing pg_aggregate.aggserialtype and adjusting signatures of assorted built-in functions. David Rowley and Tom Lane Discussion: <27247.1466185504@sss.pgh.pa.us>
2016-06-22 22:52:41 +02:00
* Serialization is only needed/allowed for transtype INTERNAL.
*/
if (transTypeId != INTERNALOID)
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
Fix type-safety problem with parallel aggregate serial/deserialization. The original specification for this called for the deserialization function to have signature "deserialize(serialtype) returns transtype", which is a security violation if transtype is INTERNAL (which it always would be in practice) and serialtype is not (which ditto). The patch blithely overrode the opr_sanity check for that, which was sloppy-enough work in itself, but the indisputable reason this cannot be allowed to stand is that CREATE FUNCTION will reject such a signature and thus it'd be impossible for extensions to create parallelizable aggregates. The minimum fix to make the signature type-safe is to add a second, dummy argument of type INTERNAL. But to lock it down a bit more and make misuse of INTERNAL-accepting functions less likely, let's get rid of the ability to specify a "serialtype" for an aggregate and just say that the only useful serialtype is BYTEA --- which, in practice, is the only interesting value anyway, due to the usefulness of the send/recv infrastructure for this purpose. That means we only have to allow "serialize(internal) returns bytea" and "deserialize(bytea, internal) returns internal" as the signatures for these support functions. In passing fix bogus signature of int4_avg_combine, which I found thanks to adding an opr_sanity check on combinefunc signatures. catversion bump due to removing pg_aggregate.aggserialtype and adjusting signatures of assorted built-in functions. David Rowley and Tom Lane Discussion: <27247.1466185504@sss.pgh.pa.us>
2016-06-22 22:52:41 +02:00
errmsg("serialization functions may be specified only when the aggregate transition data type is %s",
format_type_be(INTERNALOID))));
}
Fix type-safety problem with parallel aggregate serial/deserialization. The original specification for this called for the deserialization function to have signature "deserialize(serialtype) returns transtype", which is a security violation if transtype is INTERNAL (which it always would be in practice) and serialtype is not (which ditto). The patch blithely overrode the opr_sanity check for that, which was sloppy-enough work in itself, but the indisputable reason this cannot be allowed to stand is that CREATE FUNCTION will reject such a signature and thus it'd be impossible for extensions to create parallelizable aggregates. The minimum fix to make the signature type-safe is to add a second, dummy argument of type INTERNAL. But to lock it down a bit more and make misuse of INTERNAL-accepting functions less likely, let's get rid of the ability to specify a "serialtype" for an aggregate and just say that the only useful serialtype is BYTEA --- which, in practice, is the only interesting value anyway, due to the usefulness of the send/recv infrastructure for this purpose. That means we only have to allow "serialize(internal) returns bytea" and "deserialize(bytea, internal) returns internal" as the signatures for these support functions. In passing fix bogus signature of int4_avg_combine, which I found thanks to adding an opr_sanity check on combinefunc signatures. catversion bump due to removing pg_aggregate.aggserialtype and adjusting signatures of assorted built-in functions. David Rowley and Tom Lane Discussion: <27247.1466185504@sss.pgh.pa.us>
2016-06-22 22:52:41 +02:00
else if (serialfuncName || deserialfuncName)
{
/*
Fix type-safety problem with parallel aggregate serial/deserialization. The original specification for this called for the deserialization function to have signature "deserialize(serialtype) returns transtype", which is a security violation if transtype is INTERNAL (which it always would be in practice) and serialtype is not (which ditto). The patch blithely overrode the opr_sanity check for that, which was sloppy-enough work in itself, but the indisputable reason this cannot be allowed to stand is that CREATE FUNCTION will reject such a signature and thus it'd be impossible for extensions to create parallelizable aggregates. The minimum fix to make the signature type-safe is to add a second, dummy argument of type INTERNAL. But to lock it down a bit more and make misuse of INTERNAL-accepting functions less likely, let's get rid of the ability to specify a "serialtype" for an aggregate and just say that the only useful serialtype is BYTEA --- which, in practice, is the only interesting value anyway, due to the usefulness of the send/recv infrastructure for this purpose. That means we only have to allow "serialize(internal) returns bytea" and "deserialize(bytea, internal) returns internal" as the signatures for these support functions. In passing fix bogus signature of int4_avg_combine, which I found thanks to adding an opr_sanity check on combinefunc signatures. catversion bump due to removing pg_aggregate.aggserialtype and adjusting signatures of assorted built-in functions. David Rowley and Tom Lane Discussion: <27247.1466185504@sss.pgh.pa.us>
2016-06-22 22:52:41 +02:00
* Cannot specify one function without the other.
*/
Fix type-safety problem with parallel aggregate serial/deserialization. The original specification for this called for the deserialization function to have signature "deserialize(serialtype) returns transtype", which is a security violation if transtype is INTERNAL (which it always would be in practice) and serialtype is not (which ditto). The patch blithely overrode the opr_sanity check for that, which was sloppy-enough work in itself, but the indisputable reason this cannot be allowed to stand is that CREATE FUNCTION will reject such a signature and thus it'd be impossible for extensions to create parallelizable aggregates. The minimum fix to make the signature type-safe is to add a second, dummy argument of type INTERNAL. But to lock it down a bit more and make misuse of INTERNAL-accepting functions less likely, let's get rid of the ability to specify a "serialtype" for an aggregate and just say that the only useful serialtype is BYTEA --- which, in practice, is the only interesting value anyway, due to the usefulness of the send/recv infrastructure for this purpose. That means we only have to allow "serialize(internal) returns bytea" and "deserialize(bytea, internal) returns internal" as the signatures for these support functions. In passing fix bogus signature of int4_avg_combine, which I found thanks to adding an opr_sanity check on combinefunc signatures. catversion bump due to removing pg_aggregate.aggserialtype and adjusting signatures of assorted built-in functions. David Rowley and Tom Lane Discussion: <27247.1466185504@sss.pgh.pa.us>
2016-06-22 22:52:41 +02:00
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("must specify both or neither of serialization and deserialization functions")));
}
/*
* If a moving-aggregate transtype is specified, look that up. Same
* restrictions as for transtype.
*/
if (mtransType)
{
mtransTypeId = typenameTypeId(NULL, mtransType);
mtransTypeType = get_typtype(mtransTypeId);
if (mtransTypeType == TYPTYPE_PSEUDO &&
!IsPolymorphicType(mtransTypeId))
{
if (mtransTypeId == INTERNALOID && superuser())
/* okay */ ;
else
ereport(ERROR,
(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
errmsg("aggregate transition data type cannot be %s",
format_type_be(mtransTypeId))));
}
}
/*
* If we have an initval, and it's not for a pseudotype (particularly a
* polymorphic type), make sure it's acceptable to the type's input
* function. We will store the initval as text, because the input
* function isn't necessarily immutable (consider "now" for timestamp),
* and we want to use the runtime not creation-time interpretation of the
* value. However, if it's an incorrect value it seems much more
* user-friendly to complain at CREATE AGGREGATE time.
*/
if (initval && transTypeType != TYPTYPE_PSEUDO)
{
Oid typinput,
typioparam;
getTypeInputInfo(transTypeId, &typinput, &typioparam);
(void) OidInputFunctionCall(typinput, initval, typioparam, -1);
}
/*
* Likewise for moving-aggregate initval.
*/
if (minitval && mtransTypeType != TYPTYPE_PSEUDO)
{
Oid typinput,
typioparam;
getTypeInputInfo(mtransTypeId, &typinput, &typioparam);
(void) OidInputFunctionCall(typinput, minitval, typioparam, -1);
}
if (parallel)
{
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
if (strcmp(parallel, "safe") == 0)
proparallel = PROPARALLEL_SAFE;
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(parallel, "restricted") == 0)
proparallel = PROPARALLEL_RESTRICTED;
Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. We have a lot of code in which option names, which from the user's viewpoint are logically keywords, are passed through the grammar as plain identifiers, and then matched to string literals during command execution. This approach avoids making words into lexer keywords unnecessarily. Some places matched these strings using plain strcmp, some using pg_strcasecmp. But the latter should be unnecessary since identifiers would have been downcased on their way through the parser. Aside from any efficiency concerns (probably not a big factor), the lack of consistency in this area creates a hazard of subtle bugs due to different places coming to different conclusions about whether two option names are the same or different. Hence, standardize on using strcmp() to match any option names that are expected to have been fed through the parser. This does create a user-visible behavioral change, which is that while formerly all of these would work: alter table foo set (fillfactor = 50); alter table foo set (FillFactor = 50); alter table foo set ("fillfactor" = 50); alter table foo set ("FillFactor" = 50); now the last case will fail because that double-quoted identifier is different from the others. However, none of our documentation says that you can use a quoted identifier in such contexts at all, and we should discourage doing so since it would break if we ever decide to parse such constructs as true lexer keywords rather than poor man's substitutes. So this shouldn't create a significant compatibility issue for users. Daniel Gustafsson, reviewed by Michael Paquier, small changes by me Discussion: https://postgr.es/m/29405B24-564E-476B-98C0-677A29805B84@yesql.se
2018-01-27 00:25:02 +01:00
else if (strcmp(parallel, "unsafe") == 0)
proparallel = PROPARALLEL_UNSAFE;
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("parameter \"parallel\" must be SAFE, RESTRICTED, or UNSAFE")));
}
/*
* Most of the argument-checking is done inside of AggregateCreate
*/
return AggregateCreate(aggName, /* aggregate name */
aggNamespace, /* namespace */
replace,
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
aggKind,
numArgs,
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
numDirectArgs,
parameterTypes,
PointerGetDatum(allParameterTypes),
PointerGetDatum(parameterModes),
PointerGetDatum(parameterNames),
parameterDefaults,
Support ordered-set (WITHIN GROUP) aggregates. This patch introduces generic support for ordered-set and hypothetical-set aggregate functions, as well as implementations of the instances defined in SQL:2008 (percentile_cont(), percentile_disc(), rank(), dense_rank(), percent_rank(), cume_dist()). We also added mode() though it is not in the spec, as well as versions of percentile_cont() and percentile_disc() that can compute multiple percentile values in one pass over the data. Unlike the original submission, this patch puts full control of the sorting process in the hands of the aggregate's support functions. To allow the support functions to find out how they're supposed to sort, a new API function AggGetAggref() is added to nodeAgg.c. This allows retrieval of the aggregate call's Aggref node, which may have other uses beyond the immediate need. There is also support for ordered-set aggregates to install cleanup callback functions, so that they can be sure that infrastructure such as tuplesort objects gets cleaned up. In passing, make some fixes in the recently-added support for variadic aggregates, and make some editorial adjustments in the recent FILTER additions for aggregates. Also, simplify use of IsBinaryCoercible() by allowing it to succeed whenever the target type is ANY or ANYELEMENT. It was inconsistent that it dealt with other polymorphic target types but not these. Atri Sharma and Andrew Gierth; reviewed by Pavel Stehule and Vik Fearing, and rather heavily editorialized upon by Tom Lane
2013-12-23 22:11:35 +01:00
variadicArgType,
transfuncName, /* step function name */
finalfuncName, /* final function name */
combinefuncName, /* combine function name */
serialfuncName, /* serial function name */
deserialfuncName, /* deserial function name */
mtransfuncName, /* fwd trans function name */
minvtransfuncName, /* inv trans function name */
mfinalfuncName, /* final function name */
Allow polymorphic aggregates to have non-polymorphic state data types. Before 9.4, such an aggregate couldn't be declared, because its final function would have to have polymorphic result type but no polymorphic argument, which CREATE FUNCTION would quite properly reject. The ordered-set-aggregate patch found a workaround: allow the final function to be declared as accepting additional dummy arguments that have types matching the aggregate's regular input arguments. However, we failed to notice that this problem applies just as much to regular aggregates, despite the fact that we had a built-in regular aggregate array_agg() that was known to be undeclarable in SQL because its final function had an illegal signature. So what we should have done, and what this patch does, is to decouple the extra-dummy-arguments behavior from ordered-set aggregates and make it generally available for all aggregate declarations. We have to put this into 9.4 rather than waiting till later because it slightly alters the rules for declaring ordered-set aggregates. The patch turned out a bit bigger than I'd hoped because it proved necessary to record the extra-arguments option in a new pg_aggregate column. I'd thought we could just look at the final function's pronargs at runtime, but that didn't work well for variadic final functions. It's probably just as well though, because it simplifies life for pg_dump to record the option explicitly. While at it, fix array_agg() to have a valid final-function signature, and add an opr_sanity test to notice future deviations from polymorphic consistency. I also marked the percentile_cont() aggregates as not needing extra arguments, since they don't.
2014-04-24 01:17:31 +02:00
finalfuncExtraArgs,
mfinalfuncExtraArgs,
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
finalfuncModify,
mfinalfuncModify,
sortoperatorName, /* sort operator name */
transTypeId, /* transition data type */
transSpace, /* transition space */
mtransTypeId, /* transition data type */
mtransSpace, /* transition space */
initval, /* initial condition */
minitval, /* initial condition */
proparallel); /* parallel safe? */
}
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
/*
* Convert the string form of [m]finalfunc_modify to the catalog representation
*/
static char
extractModify(DefElem *defel)
{
char *val = defGetString(defel);
if (strcmp(val, "read_only") == 0)
return AGGMODIFY_READ_ONLY;
if (strcmp(val, "shareable") == 0)
return AGGMODIFY_SHAREABLE;
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
if (strcmp(val, "read_write") == 0)
return AGGMODIFY_READ_WRITE;
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("parameter \"%s\" must be READ_ONLY, SHAREABLE, or READ_WRITE",
Explicitly track whether aggregate final functions modify transition state. Up to now, there's been hard-wired assumptions that normal aggregates' final functions never modify their transition states, while ordered-set aggregates' final functions always do. This has always been a bit limiting, and in particular it's getting in the way of improving the built-in ordered-set aggregates to allow merging of transition states. Therefore, let's introduce catalog and CREATE AGGREGATE infrastructure that lets the finalfn's behavior be declared explicitly. There are now three possibilities for the finalfn behavior: it's purely read-only, it trashes the transition state irrecoverably, or it changes the state in such a way that no more transfn calls are possible but the state can still be passed to other, compatible finalfns. There are no examples of this third case today, but we'll shortly make the built-in OSAs act like that. This change allows user-defined aggregates to explicitly disclaim support for use as window functions, and/or to prevent transition state merging, if their implementations cannot handle that. While it was previously possible to handle the window case with a run-time error check, there was not any way to prevent transition state merging, which in retrospect is something commit 804163bc2 should have provided for. But better late than never. In passing, split out pg_aggregate.c's extern function declarations into a new header file pg_aggregate_fn.h, similarly to what we've done for some other catalog headers, so that pg_aggregate.h itself can be safe for frontend files to include. This lets pg_dump use the symbolic names for relevant constants. Discussion: https://postgr.es/m/4834.1507849699@sss.pgh.pa.us
2017-10-14 21:21:39 +02:00
defel->defname)));
return 0; /* keep compiler quiet */
}