Re: Row pattern recognition

Attached is the v4 patch. Differences from previous patch include:

> - PERMUTE is still misspelled as PREMUTE

Fixed.

> - PATTERN variables do not have to exist in the DEFINE clause.  They are
> - considered TRUE if not present.

Fixed. Moreover new regression test case is added.

- It was possible that tle nodes in DEFINE clause do not appear in the
  plan's target list. This makes impossible to evaluate expressions in
  the DEFINE because it does not appear in the outer plan's target
  list. To fix this, call findTargetlistEntrySQL99 (with resjunk is
  true) so that the missing TargetEntry is added to the outer plan
  later on.

- I eliminated some hacks in handling the Var node in DEFINE
  clause. Previously I replaced varattno of Var node in a plan tree by
  hand so that it refers to correct varattno in the outer plan
  node. In this patch I modified set_upper_references so that it calls
  fix_upper_expr for those Var nodes in the DEFINE clause. See v4-0003
  patch for more details.

- I found a bug with pattern matching code. It creates a string for
  subsequent regular expression matching. It uses the initial letter
  of each define variable name. For example, if the varname is "foo",
  then "f" is used. Obviously this makes trouble if we have two or
  more variables starting with same "f" (e.g. "food"). To fix this, I
  assign [a-z] to each variable instead of its initial letter. However
  this way limits us not to have more than 26 variables. I hope 26 is
  enough for most use cases.

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