Re: Row pattern recognition

Hi Henson,

The merged v38 patch passed CI check:
https://cirrus-ci.com/github/postgresql-cfbot/postgresql/cf%2F4460

Congratulations!

>> Summary of changes:
> 
> Will check.

I have one question regaring your patch.

In update_reduced_frame():
+    hasLimitedFrame = (frameOptions & FRAMEOPTION_ROWS) &&
+                      !(frameOptions & FRAMEOPTION_END_UNBOUNDED_FOLLOWING);
+    if (hasLimitedFrame && winstate->endOffsetValue != 0)
+        frameOffset = DatumGetInt64(winstate->endOffsetValue);

frameOffset is a offset value n from "ROWS BETWEEN CURRENT ROW AND n FOLLOWING".
Later you use this here:

+    ctxFrameEnd = ctx->matchStartRow + frameOffset + 1;

So my question is, how do you ensure that ctxFrameEnd does not go
beyond the full window frame end?

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