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postgres/src/include/parser/parse_agg.h

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Break parser functions into smaller files, group together.
1997-11-25 22:07:18 +00:00
/*-------------------------------------------------------------------------
*
* parse_agg.h
Support window functions a la SQL:2008. Hitoshi Harada, with some kibitzing from Heikki and Tom.
2008-12-28 18:54:01 +00:00
* handle aggregates and window functions in parser
Break parser functions into smaller files, group together.
1997-11-25 22:07:18 +00:00
*
Update copyright via script for 2017
2017-01-03 13:48:53 -05:00
* Portions Copyright (c) 1996-2017, PostgreSQL Global Development Group
Add: * Portions Copyright (c) 1996-2000, PostgreSQL, Inc to all files copyright Regents of Berkeley. Man, that's a lot of files.
2000-01-26 05:58:53 +00:00
* Portions Copyright (c) 1994, Regents of the University of California
Break parser functions into smaller files, group together.
1997-11-25 22:07:18 +00:00
*
Remove cvs keywords from all files.
2010-09-20 22:08:53 +02:00
* src/include/parser/parse_agg.h
Break parser functions into smaller files, group together.
1997-11-25 22:07:18 +00:00
*
*-------------------------------------------------------------------------
*/
#ifndef PARSE_AGG_H
#define PARSE_AGG_H
Change #include's to use <> and "" as appropriate.
1999-07-15 23:04:24 +00:00
#include "parser/parse_node.h"
Break parser functions into smaller files, group together.
1997-11-25 22:07:18 +00:00
Support ORDER BY within aggregate function calls, at long last providing a non-kluge method for controlling the order in which values are fed to an aggregate function. At the same time eliminate the old implementation restriction that DISTINCT was only supported for single-argument aggregates. Possibly release-notable behavioral change: formerly, agg(DISTINCT x) dropped null values of x unconditionally. Now, it does so only if the agg transition function is strict; otherwise nulls are treated as DISTINCT normally would, ie, you get one copy. Andrew Gierth, reviewed by Hitoshi Harada
2009-12-15 17:57:48 +00:00
extern void transformAggregateCall(ParseState *pstate, Aggref *agg,
Pass incompletely-transformed aggregate argument lists as separate parameters to transformAggregateCall, instead of abusing fields in Aggref to carry them temporarily. No change in functionality but hopefully the code is a bit clearer now. Per gripe from Gokulakannan Somasundaram.
2010-03-17 16:52:38 +00:00
List *args, List *aggorder,
pgindent run for 9.0
2010-02-26 02:01:40 +00:00
bool agg_distinct);
Support GROUPING SETS, CUBE and ROLLUP. This SQL standard functionality allows to aggregate data by different GROUP BY clauses at once. Each grouping set returns rows with columns grouped by in other sets set to NULL. This could previously be achieved by doing each grouping as a separate query, conjoined by UNION ALLs. Besides being considerably more concise, grouping sets will in many cases be faster, requiring only one scan over the underlying data. The current implementation of grouping sets only supports using sorting for input. Individual sets that share a sort order are computed in one pass. If there are sets that don't share a sort order, additional sort & aggregation steps are performed. These additional passes are sourced by the previous sort step; thus avoiding repeated scans of the source data. The code is structured in a way that adding support for purely using hash aggregation or a mix of hashing and sorting is possible. Sorting was chosen to be supported first, as it is the most generic method of implementation. Instead of, as in an earlier versions of the patch, representing the chain of sort and aggregation steps as full blown planner and executor nodes, all but the first sort are performed inside the aggregation node itself. This avoids the need to do some unusual gymnastics to handle having to return aggregated and non-aggregated tuples from underlying nodes, as well as having to shut down underlying nodes early to limit memory usage. The optimizer still builds Sort/Agg node to describe each phase, but they're not part of the plan tree, but instead additional data for the aggregation node. They're a convenient and preexisting way to describe aggregation and sorting. The first (and possibly only) sort step is still performed as a separate execution step. That retains similarity with existing group by plans, makes rescans fairly simple, avoids very deep plans (leading to slow explains) and easily allows to avoid the sorting step if the underlying data is sorted by other means. A somewhat ugly side of this patch is having to deal with a grammar ambiguity between the new CUBE keyword and the cube extension/functions named cube (and rollup). To avoid breaking existing deployments of the cube extension it has not been renamed, neither has cube been made a reserved keyword. Instead precedence hacking is used to make GROUP BY cube(..) refer to the CUBE grouping sets feature, and not the function cube(). To actually group by a function cube(), unlikely as that might be, the function name has to be quoted. Needs a catversion bump because stored rules may change. Author: Andrew Gierth and Atri Sharma, with contributions from Andres Freund Reviewed-By: Andres Freund, Noah Misch, Tom Lane, Svenne Krap, Tomas Vondra, Erik Rijkers, Marti Raudsepp, Pavel Stehule Discussion: CAOeZVidmVRe2jU6aMk_5qkxnB7dfmPROzM7Ur8JPW5j8Y5X-Lw@mail.gmail.com
2015-05-16 03:40:59 +02:00
extern Node *transformGroupingFunc(ParseState *pstate, GroupingFunc *g);
Support window functions a la SQL:2008. Hitoshi Harada, with some kibitzing from Heikki and Tom.
2008-12-28 18:54:01 +00:00
extern void transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc,
8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef list provided by Andrew.
2009-06-11 14:49:15 +00:00
WindowDef *windef);
Implement outer-level aggregates to conform to the SQL spec, with extensions to support our historical behavior. An aggregate belongs to the closest query level of any of the variables in its argument, or the current query level if there are no variables (e.g., COUNT(*)). The implementation involves adding an agglevelsup field to Aggref, and treating outer aggregates like outer variables at planning time.
2003-06-06 15:04:03 +00:00
Fix parse_agg.c to detect ungrouped Vars in sub-SELECTs; remove code that used to do it in planner. That was an ancient kluge that was never satisfactory; errors should be detected at parse time when possible. But at the time we didn't have the support mechanism (expression_tree_walker et al) to make it convenient to do in the parser.
2003-01-17 03:25:04 +00:00
extern void parseCheckAggregates(ParseState *pstate, Query *qry);
Another pgindent run. Fixes enum indenting, and improves #endif spacing. Also adds space for one-line comments.
2001-10-28 06:26:15 +00:00
Support GROUPING SETS, CUBE and ROLLUP. This SQL standard functionality allows to aggregate data by different GROUP BY clauses at once. Each grouping set returns rows with columns grouped by in other sets set to NULL. This could previously be achieved by doing each grouping as a separate query, conjoined by UNION ALLs. Besides being considerably more concise, grouping sets will in many cases be faster, requiring only one scan over the underlying data. The current implementation of grouping sets only supports using sorting for input. Individual sets that share a sort order are computed in one pass. If there are sets that don't share a sort order, additional sort & aggregation steps are performed. These additional passes are sourced by the previous sort step; thus avoiding repeated scans of the source data. The code is structured in a way that adding support for purely using hash aggregation or a mix of hashing and sorting is possible. Sorting was chosen to be supported first, as it is the most generic method of implementation. Instead of, as in an earlier versions of the patch, representing the chain of sort and aggregation steps as full blown planner and executor nodes, all but the first sort are performed inside the aggregation node itself. This avoids the need to do some unusual gymnastics to handle having to return aggregated and non-aggregated tuples from underlying nodes, as well as having to shut down underlying nodes early to limit memory usage. The optimizer still builds Sort/Agg node to describe each phase, but they're not part of the plan tree, but instead additional data for the aggregation node. They're a convenient and preexisting way to describe aggregation and sorting. The first (and possibly only) sort step is still performed as a separate execution step. That retains similarity with existing group by plans, makes rescans fairly simple, avoids very deep plans (leading to slow explains) and easily allows to avoid the sorting step if the underlying data is sorted by other means. A somewhat ugly side of this patch is having to deal with a grammar ambiguity between the new CUBE keyword and the cube extension/functions named cube (and rollup). To avoid breaking existing deployments of the cube extension it has not been renamed, neither has cube been made a reserved keyword. Instead precedence hacking is used to make GROUP BY cube(..) refer to the CUBE grouping sets feature, and not the function cube(). To actually group by a function cube(), unlikely as that might be, the function name has to be quoted. Needs a catversion bump because stored rules may change. Author: Andrew Gierth and Atri Sharma, with contributions from Andres Freund Reviewed-By: Andres Freund, Noah Misch, Tom Lane, Svenne Krap, Tomas Vondra, Erik Rijkers, Marti Raudsepp, Pavel Stehule Discussion: CAOeZVidmVRe2jU6aMk_5qkxnB7dfmPROzM7Ur8JPW5j8Y5X-Lw@mail.gmail.com
2015-05-16 03:40:59 +02:00
extern List *expand_grouping_sets(List *groupingSets, int limit);
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 16:11:35 -05:00
extern int get_aggregate_argtypes(Aggref *aggref, Oid *inputTypes);
extern Oid resolve_aggregate_transtype(Oid aggfuncid,
Oid aggtranstype,
Oid *inputTypes,
int numArguments);
Share transition state between different aggregates when possible. If there are two different aggregates in the query with same inputs, and the aggregates have the same initial condition and transition function, only calculate the state value once, and only call the final functions separately. For example, AVG(x) and SUM(x) aggregates have the same transition function, which accumulates the sum and number of input tuples. For a query like "SELECT AVG(x), SUM(x) FROM x", we can therefore accumulate the state function only once, which gives a nice speedup. David Rowley, reviewed and edited by me.
2015-08-04 17:53:10 +03:00
extern void build_aggregate_transfn_expr(Oid *agg_input_types,
pgindent run for 9.6
2016-06-09 18:02:36 -04:00
int agg_num_inputs,
int agg_num_direct_inputs,
bool agg_variadic,
Oid agg_state_type,
Oid agg_input_collation,
Oid transfn_oid,
Oid invtransfn_oid,
Expr **transfnexpr,
Expr **invtransfnexpr);
Share transition state between different aggregates when possible. If there are two different aggregates in the query with same inputs, and the aggregates have the same initial condition and transition function, only calculate the state value once, and only call the final functions separately. For example, AVG(x) and SUM(x) aggregates have the same transition function, which accumulates the sum and number of input tuples. For a query like "SELECT AVG(x), SUM(x) FROM x", we can therefore accumulate the state function only once, which gives a nice speedup. David Rowley, reviewed and edited by me.
2015-08-04 17:53:10 +03:00
Support multi-stage aggregation. Aggregate nodes now have two new modes: a "partial" mode where they output the unfinalized transition state, and a "finalize" mode where they accept unfinalized transition states rather than individual values as input. These new modes are not used anywhere yet, but they will be necessary for parallel aggregation. The infrastructure also figures to be useful for cases where we want to aggregate local data and remote data via the FDW interface, and want to bring back partial aggregates from the remote side that can then be combined with locally generated partial aggregates to produce the final value. It may also be useful even when neither FDWs nor parallelism are in play, as explained in the comments in nodeAgg.c. David Rowley and Simon Riggs, reviewed by KaiGai Kohei, Heikki Linnakangas, Haribabu Kommi, and me.
2016-01-20 13:46:50 -05:00
extern void build_aggregate_combinefn_expr(Oid agg_state_type,
pgindent run for 9.6
2016-06-09 18:02:36 -04:00
Oid agg_input_collation,
Oid combinefn_oid,
Expr **combinefnexpr);
Support multi-stage aggregation. Aggregate nodes now have two new modes: a "partial" mode where they output the unfinalized transition state, and a "finalize" mode where they accept unfinalized transition states rather than individual values as input. These new modes are not used anywhere yet, but they will be necessary for parallel aggregation. The infrastructure also figures to be useful for cases where we want to aggregate local data and remote data via the FDW interface, and want to bring back partial aggregates from the remote side that can then be combined with locally generated partial aggregates to produce the final value. It may also be useful even when neither FDWs nor parallelism are in play, as explained in the comments in nodeAgg.c. David Rowley and Simon Riggs, reviewed by KaiGai Kohei, Heikki Linnakangas, Haribabu Kommi, and me.
2016-01-20 13:46:50 -05:00
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 16:52:41 -04:00
extern void build_aggregate_serialfn_expr(Oid serialfn_oid,
pgindent run for 9.6
2016-06-09 18:02:36 -04:00
Expr **serialfnexpr);
Allow aggregate transition states to be serialized and deserialized. This is necessary infrastructure for supporting parallel aggregation for aggregates whose transition type is "internal". Such values can't be passed between cooperating processes, because they are just pointers. David Rowley, reviewed by Tomas Vondra and by me.
2016-03-29 15:04:05 -04:00
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 16:52:41 -04:00
extern void build_aggregate_deserialfn_expr(Oid deserialfn_oid,
Expr **deserialfnexpr);
Share transition state between different aggregates when possible. If there are two different aggregates in the query with same inputs, and the aggregates have the same initial condition and transition function, only calculate the state value once, and only call the final functions separately. For example, AVG(x) and SUM(x) aggregates have the same transition function, which accumulates the sum and number of input tuples. For a query like "SELECT AVG(x), SUM(x) FROM x", we can therefore accumulate the state function only once, which gives a nice speedup. David Rowley, reviewed and edited by me.
2015-08-04 17:53:10 +03:00
extern void build_aggregate_finalfn_expr(Oid *agg_input_types,
pgindent run for 9.6
2016-06-09 18:02:36 -04:00
int num_finalfn_inputs,
Oid agg_state_type,
Oid agg_result_type,
Oid agg_input_collation,
Oid finalfn_oid,
Expr **finalfnexpr);
Aggregates can be polymorphic, using polymorphic implementation functions. It also works to create a non-polymorphic aggregate from polymorphic functions, should you want to do that. Regression test added, docs still lacking. By Joe Conway, with some kibitzing from Tom Lane.
2003-07-01 19:10:53 +00:00
New pgindent run with fixes suggested by Tom. Patch manually reviewed, initdb/regression tests pass.
2001-11-05 17:46:40 +00:00
#endif /* PARSE_AGG_H */
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