Re: Row pattern recognition

> Hi,
> 
> The patches compile & tests run fine but this statement from the
> documentation crashes an assert-enabled server:
> 
> SELECT company, tdate, price, max(price) OVER w FROM stock
> WINDOW w AS (
> PARTITION BY company
> ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
> AFTER MATCH SKIP PAST LAST ROW
> INITIAL
> PATTERN (LOWPRICE UP+ DOWN+)
> DEFINE
> LOWPRICE AS price <= 100,
> UP AS price > PREV(price),
> DOWN AS price < PREV(price)
> );
> server closed the connection unexpectedly
> 	This probably means the server terminated abnormally
> 	before or while processing the request.
> connection to server was lost

Thank you for the report. Currently the patch has an issue with
aggregate functions including max. I have been working on aggregations
in row pattern recognition but will take more time to complete the
part.

In the mean time if you want to play with RPR, you can try window
functions. Examples can be found in src/test/regress/sql/rpr.sql.
Here is one of this:

-- the first row start with less than or equal to 100
SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
 FROM stock
 WINDOW w AS (
 PARTITION BY company
 ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
 INITIAL
 PATTERN (LOWPRICE UP+ DOWN+)
 DEFINE
  LOWPRICE AS price <= 100,
  UP AS price > PREV(price),
  DOWN AS price < PREV(price)
);

-- second row raises 120%
SELECT company, tdate, price, first_value(price) OVER w, last_value(price) OVER w
 FROM stock
 WINDOW w AS (
 PARTITION BY company
 ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
 INITIAL
 PATTERN (LOWPRICE UP+ DOWN+)
 DEFINE
  LOWPRICE AS price <= 100,
  UP AS price > PREV(price) * 1.2,
  DOWN AS price < PREV(price)
);

Sorry for inconvenience.

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp