Horton

Re: Assert triggered during RE_compile_and_cache

Mark Dilger <mark.dilger@enterprisedb.com>

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From: Mark Dilger <mark.dilger@enterprisedb.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2021-08-08T17:00:10Z
Lists: pgsql-hackers 

> On Aug 8, 2021, at 9:31 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> 
> I realized that the earlier patch is actually a bad idea

Applying only your <fix-backref-corner-case-1.patch> to master, the following which did not crash begins to crash:

 select regexp_split_to_array('rjgykkkk', '(?:(.))((\1\1.))');

It also changes the results for another one:

 select regexp_split_to_array('jdpveoarcnsarcnsarcnszieqbqbqbqbiufdlywphbnrxtdoboouuzcqiqmenj', '()((.)){1}?\3?', 'itx');
-                                                                                     regexp_split_to_array                                                                                      
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
- {"","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","","",""}
+                      regexp_split_to_array                       
+------------------------------------------------------------------
+ {jdpveoarcnsarcnsarcnszieqbqbqbqbiufdlywphbnrxtdoboouuzcqiqmenj}

I'm not sure what *should* be returned here, only that it is a behavioral change.

—
Mark Dilger
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

Commits

  1. Check the size in COPY_POINTER_FIELD

  2. Rethink regexp engine's backref-related compilation state.

  3. Fix use-after-free issue in regexp engine.

  4. Make regexp engine's backref-related compilation state more bulletproof.

  5. Really fix the ambiguity in REFRESH MATERIALIZED VIEW CONCURRENTLY.

  6. Avoid generating extra subre tree nodes for capturing parentheses.