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postgresql/contrib/tablefunc/tablefunc.h

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As mentioned above, here is my contrib/tablefunc patch. It includes three functions which exercise the tablefunc API. show_all_settings() - returns the same information as SHOW ALL, but as a query result normal_rand(int numvals, float8 mean, float8 stddev, int seed) - returns a set of normally distributed float8 values - This routine implements Algorithm P (Polar method for normal deviates) from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. crosstabN(text sql) - returns a set of row_name plus N category value columns - crosstab2(), crosstab3(), and crosstab4() are defined for you, but you can create additional crosstab functions per directions in the README. Joe Conway
2002-07-31 00:31:11 +08:00
/*
* tablefunc
*
* Sample to demonstrate C functions which return setof scalar
* and setof composite.
* Joe Conway <mail@joeconway.com>
> Am Son, 2003-06-22 um 02.09 schrieb Joe Conway: >>Sounds like all that's needed for your case. But to be complete, in >>addition to changing tablefunc.c we'd have to: >>1) come up with a new function call signature that makes sense and does >>not cause backward compatibility problems for other people >>2) make needed changes to tablefunc.sql.in >>3) adjust the README.tablefunc appropriately >>4) adjust the regression test for new functionality >>5) be sure we don't break any of the old cases >> >>If you want to submit a complete patch, it would be gratefully accepted >>-- for review at least ;-) > > Here's the patch, at least for steps 1-3 Nabil Sayegh Joe Conway
2003-07-27 11:51:59 +08:00
* And contributors:
* Nabil Sayegh <postgresql@e-trolley.de>
As mentioned above, here is my contrib/tablefunc patch. It includes three functions which exercise the tablefunc API. show_all_settings() - returns the same information as SHOW ALL, but as a query result normal_rand(int numvals, float8 mean, float8 stddev, int seed) - returns a set of normally distributed float8 values - This routine implements Algorithm P (Polar method for normal deviates) from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. crosstabN(text sql) - returns a set of row_name plus N category value columns - crosstab2(), crosstab3(), and crosstab4() are defined for you, but you can create additional crosstab functions per directions in the README. Joe Conway
2002-07-31 00:31:11 +08:00
*
Update copyright to 2004.
2004-08-29 12:13:13 +08:00
* Copyright (c) 2002-2004, PostgreSQL Global Development Group
As mentioned above, here is my contrib/tablefunc patch. It includes three functions which exercise the tablefunc API. show_all_settings() - returns the same information as SHOW ALL, but as a query result normal_rand(int numvals, float8 mean, float8 stddev, int seed) - returns a set of normally distributed float8 values - This routine implements Algorithm P (Polar method for normal deviates) from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. crosstabN(text sql) - returns a set of row_name plus N category value columns - crosstab2(), crosstab3(), and crosstab4() are defined for you, but you can create additional crosstab functions per directions in the README. Joe Conway
2002-07-31 00:31:11 +08:00
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without a written agreement
* is hereby granted, provided that the above copyright notice and this
* paragraph and the following two paragraphs appear in all copies.
pgindent run.
2002-09-05 04:31:48 +08:00
*
As mentioned above, here is my contrib/tablefunc patch. It includes three functions which exercise the tablefunc API. show_all_settings() - returns the same information as SHOW ALL, but as a query result normal_rand(int numvals, float8 mean, float8 stddev, int seed) - returns a set of normally distributed float8 values - This routine implements Algorithm P (Polar method for normal deviates) from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. crosstabN(text sql) - returns a set of row_name plus N category value columns - crosstab2(), crosstab3(), and crosstab4() are defined for you, but you can create additional crosstab functions per directions in the README. Joe Conway
2002-07-31 00:31:11 +08:00
* IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
* LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
* DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
pgindent run.
2002-09-05 04:31:48 +08:00
*
As mentioned above, here is my contrib/tablefunc patch. It includes three functions which exercise the tablefunc API. show_all_settings() - returns the same information as SHOW ALL, but as a query result normal_rand(int numvals, float8 mean, float8 stddev, int seed) - returns a set of normally distributed float8 values - This routine implements Algorithm P (Polar method for normal deviates) from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. crosstabN(text sql) - returns a set of row_name plus N category value columns - crosstab2(), crosstab3(), and crosstab4() are defined for you, but you can create additional crosstab functions per directions in the README. Joe Conway
2002-07-31 00:31:11 +08:00
* THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
*/
#ifndef TABLEFUNC_H
#define TABLEFUNC_H
/*
* External declarations
*/
extern Datum normal_rand(PG_FUNCTION_ARGS);
extern Datum crosstab(PG_FUNCTION_ARGS);
Attached is an update to contrib/tablefunc. It implements a new hashed version of crosstab. This fixes a major deficiency in real-world use of the original version. Easiest to undestand with an illustration: Data: ------------------------------------------------------------------- select * from cth; id | rowid | rowdt | attribute | val ----+-------+---------------------+----------------+--------------- 1 | test1 | 2003-03-01 00:00:00 | temperature | 42 2 | test1 | 2003-03-01 00:00:00 | test_result | PASS 3 | test1 | 2003-03-01 00:00:00 | volts | 2.6987 4 | test2 | 2003-03-02 00:00:00 | temperature | 53 5 | test2 | 2003-03-02 00:00:00 | test_result | FAIL 6 | test2 | 2003-03-02 00:00:00 | test_startdate | 01 March 2003 7 | test2 | 2003-03-02 00:00:00 | volts | 3.1234 (7 rows) Original crosstab: ------------------------------------------------------------------- SELECT * FROM crosstab( 'SELECT rowid, attribute, val FROM cth ORDER BY 1,2',4) AS c(rowid text, temperature text, test_result text, test_startdate text, volts text); rowid | temperature | test_result | test_startdate | volts -------+-------------+-------------+----------------+-------- test1 | 42 | PASS | 2.6987 | test2 | 53 | FAIL | 01 March 2003 | 3.1234 (2 rows) Hashed crosstab: ------------------------------------------------------------------- SELECT * FROM crosstab( 'SELECT rowid, attribute, val FROM cth ORDER BY 1', 'SELECT DISTINCT attribute FROM cth ORDER BY 1') AS c(rowid text, temperature int4, test_result text, test_startdate timestamp, volts float8); rowid | temperature | test_result | test_startdate | volts -------+-------------+-------------+---------------------+-------- test1 | 42 | PASS | | 2.6987 test2 | 53 | FAIL | 2003-03-01 00:00:00 | 3.1234 (2 rows) Notice that the original crosstab slides data over to the left in the result tuple when it encounters missing data. In order to work around this you have to be make your source sql do all sorts of contortions (cartesian join of distinct rowid with distinct attribute; left join that back to the real source data). The new version avoids this by building a hash table using a second distinct attribute query. The new version also allows for "extra" columns (see the README) and allows the result columns to be coerced into differing datatypes if they are suitable (as shown above). In testing a "real-world" data set (69 distinct rowid's, 27 distinct categories/attributes, multiple missing data points) I saw about a 5-fold improvement in execution time (from about 2200 ms old, to 440 ms new). I left the original version intact because: 1) BC, 2) it is probably slightly faster if you know that you have no missing attributes. README and regression test adjustments included. If there are no objections, please apply. Joe Conway
2003-03-20 14:46:30 +08:00
extern Datum crosstab_hash(PG_FUNCTION_ARGS);
Attached is an update to contrib/tablefunc. It introduces a new function, connectby(), which can serve as a reference implementation for the changes made in the last few days -- namely the ability of a function to return an entire tuplestore, and the ability of a function to make use of the query provided "expected" tuple description. Description: connectby(text relname, text keyid_fld, text parent_keyid_fld, text start_with, int max_depth [, text branch_delim]) - returns keyid, parent_keyid, level, and an optional branch string - requires anonymous composite type syntax in the FROM clause. See the instructions in the documentation below. Joe Conway
2002-09-02 13:44:05 +08:00
extern Datum connectby_text(PG_FUNCTION_ARGS);
> Am Son, 2003-06-22 um 02.09 schrieb Joe Conway: >>Sounds like all that's needed for your case. But to be complete, in >>addition to changing tablefunc.c we'd have to: >>1) come up with a new function call signature that makes sense and does >>not cause backward compatibility problems for other people >>2) make needed changes to tablefunc.sql.in >>3) adjust the README.tablefunc appropriately >>4) adjust the regression test for new functionality >>5) be sure we don't break any of the old cases >> >>If you want to submit a complete patch, it would be gratefully accepted >>-- for review at least ;-) > > Here's the patch, at least for steps 1-3 Nabil Sayegh Joe Conway
2003-07-27 11:51:59 +08:00
extern Datum connectby_text_serial(PG_FUNCTION_ARGS);
As mentioned above, here is my contrib/tablefunc patch. It includes three functions which exercise the tablefunc API. show_all_settings() - returns the same information as SHOW ALL, but as a query result normal_rand(int numvals, float8 mean, float8 stddev, int seed) - returns a set of normally distributed float8 values - This routine implements Algorithm P (Polar method for normal deviates) from Knuth's _The_Art_of_Computer_Programming_, Volume 2, 3rd ed., pages 122-126. Knuth cites his source as "The polar method", G. E. P. Box, M. E. Muller, and G. Marsaglia, _Annals_Math,_Stat._ 29 (1958), 610-611. crosstabN(text sql) - returns a set of row_name plus N category value columns - crosstab2(), crosstab3(), and crosstab4() are defined for you, but you can create additional crosstab functions per directions in the README. Joe Conway
2002-07-31 00:31:11 +08:00
#endif /* TABLEFUNC_H */
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