Commit Graph

10 Commits

Author SHA1 Message Date
Joe Conway
bc8a1fc282 Hashed crosstab was dying with an SPI_finish error when the source SQL
produced no rows. Now it returns 0 rows instead. Adjusted regression
test for this case.
2004-08-11 00:49:35 +00:00
Tom Lane
c472b8366f With Joe Conway's concurrence, remove srandom() call from normal_rand().
This was the last piece of code that took it upon itself to reset the
random number sequence --- now we only have srandom() in postmaster start,
backend start, and explicit setseed() operations.
2003-09-13 21:44:50 +00:00
Bruce Momjian
a265b7f70a > 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 03:51:59 +00:00
Bruce Momjian
64d0b8b05f 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 06:46:30 +00:00
Tom Lane
1f1c332381 Remove inappropriate double-quoting in connectby() code; adjust
regression test to avoid using VALUE as a name.  From Joe Conway.
2002-11-23 01:54:09 +00:00
Bruce Momjian
e5cf1a8a26 SET autocommit no longer needed in /contrib because pg_regress.sh does
it automatically now on regression session startup.
2002-10-21 01:42:14 +00:00
Bruce Momjian
aa4c702eac Update /contrib for "autocommit TO 'on'".
Create objects in public schema.

Make spacing/capitalization consistent.

Remove transaction block use for object creation.

Remove unneeded function GRANTs.
2002-10-18 18:41:22 +00:00
Bruce Momjian
a62873d279 The attached adds a bit to the contrib/tablefunc regression test for
behavior of connectby() in the presence of infinite recursion. Please
apply this one in addition to the one sent earlier.

Joe Conway
2002-10-03 17:15:36 +00:00
Tom Lane
bd04184b11 Attached is a patch to fix some recently raised issues that exist in
contrib/tablefunc. Specifically it replaces the use of VIEWs (for needed
composite type creation) with use of CREATE TYPE. It also performs GRANT
EXECUTE ON FUNCTION foo() TO PUBLIC for all of the created functions. There
was also a cosmetic change to two regression files.

Joe Conway
2002-09-14 19:53:59 +00:00
Bruce Momjian
6fff9a7475 The attached removes the current non-standard file
"contrib/tablefunc/tablefunc-test.sql", and adds a standard regression
test suite to contrib/tablefunc.

Joe Conway
2002-09-12 00:14:40 +00:00