Re: Row pattern recognition

> On Nov 19, 2025, at 12:14, Chao Li <li.evan.chao@gmail.com> wrote:
>
>
> 9 - 0002 - parse_clause.c

I am continuing to review 0003

10 - 0003
```
+    Assert(list_length(patternVariables) == list_length(defineClause));
```

Is this assert true? From what I learned, pattern length doesn’t have to equal to define length. For example, I got an
examplefrom [1]: 

```
Example 4
-- This example has three different patterns.
-- Comment two of them, to get error-free query.
SELECT company, price_date, price
  FROM stock_price
    MATCH_RECOGNIZE (
       partition by company
       order by price_date
       all rows per match
       pattern ( limit_50  up   up* down  down*  )
       define
           limit_50 as price <= 50.00,
           up   as price > prev(price),
           down as price < prev(price)
    )
   WHERE company = 'B'
   ORDER BY price_date;
```

In this example, pattern has 5 elements and define has only 3 elements.

11 - 0004 - plannodes.h
```
+    /* Row Pattern Recognition AFTER MACH SKIP clause */
+    RPSkipTo    rpSkipTo;        /* Row Pattern Skip To type */
```

Typo: MACH -> MATCH

I’d stop here, and continue 0005 tomorrow.


[1] https://link.springer.com/article/10.1007/s13222-022-00404-3

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/