Horton

Re: automatically generating node support functions

Peter Eisentraut <peter.eisentraut@enterprisedb.com>

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From: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
To: pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-02-14T10:15:57Z
Lists: pgsql-hackers 
What do people think about this patch now?

I have received some feedback on several small technical issues, which 
have all been fixed.  This patch has been around for several commit 
fests now and AFAICT, nothing has broken it.  This is just to indicate 
that the parsing isn't as flimsy as one might fear.

One thing thing that is waiting behind this patch is that you currently 
cannot put utility commands into parse-time SQL functions, because there 
is no full out/read support for those.  This patch would fix that 
problem.  (There is a little bit of additional work necessary, but I 
have that mostly worked out in a separate branch.)


On 24.01.22 16:15, Peter Eisentraut wrote:
> Rebased patch to resolve some merge conflicts
> 
> On 29.12.21 12:08, Peter Eisentraut wrote:
>> On 12.10.21 15:52, Andrew Dunstan wrote:
>>> I haven't been through the whole thing, but I did notice this: the
>>> comment stripping code looks rather fragile. I think it would blow up if
>>> there were a continuation line not starting with  qr/\s*\*/. It's a lot
>>> simpler and more robust to do this if you slurp the file in whole.
>>> Here's what we do in the buildfarm code:
>>>
>>>      my $src = file_contents($_);
>>>      # strip C comments
>>>      # We used to use the recipe in perlfaq6 but there is actually no 
>>> point.
>>>      # We don't need to keep the quoted string values anyway, and
>>>      # on some platforms the complex regex causes perl to barf and 
>>> crash.
>>>      $src =~ s{/\*.*?\*/}{}gs;
>>>
>>> After you've done that splitting it into lines is pretty simple.
>>
>> Here is an updated patch, with some general rebasing, and the above 
>> improvement.  It now also generates #include lines necessary in 
>> copyfuncs etc. to pull in all the node types it operates on.
>>
>> Further, I have looked more into the "metadata" approach discussed in 
>> [0].  It's pretty easy to generate that kind of output from the data 
>> structures my script produces.  You just loop over all the node types 
>> and print stuff and keep a few counters.  I don't plan to work on that 
>> at this time, but I just wanted to point out that if people wanted to 
>> move into that direction, my patch wouldn't be in the way.
>>
>>
>> [0]: 
>> https://www.postgresql.org/message-id/flat/20190828234136.fk2ndqtld3onfrrp%40alap3.anarazel.de 
>>

Commits

  1. Fix MSVC build script's check for obsolete node support functions.

  2. Improve performance of ORDER BY / DISTINCT aggregates

  3. doc: Fix typos in protocol.sgml

  4. Tighten up parsing logic in gen_node_support.pl.

  5. Add defenses against unexpected changes in the NodeTag enum list.

  6. Add copy/equal support for XID lists

  7. Rationalize order of input files for gen_node_support.pl.

  8. Make assorted quality-of-life improvements in gen_node_support.pl.

  9. Doc: rearrange high-level commentary about node support coverage.

  10. Automatically generate node support functions

  11. Adjust node serialization tag of A_Expr for consistency

  12. Remove T_Join and T_Plan

  13. Reformat some more node comments

  14. Reformat some node comments

  15. Remove JsonPathSpec typedef

  16. Add missing enum tag in enum used in nodes

  17. Add Cardinality typedef

  18. Make node output prefix match node structure name

  19. Add WRITE_INDEX_ARRAY

  20. Add COPY_ARRAY_FIELD and COMPARE_ARRAY_FIELD

  21. Remove T_Expr

  22. Change NestPath node to contain JoinPath node

  23. Change SeqScan node to contain Scan node

  24. Check the size in COPY_POINTER_FIELD

  25. Remove T_MemoryContext

  26. Add missing enum tags in enums used in nodes

  27. Rename some node support functions for consistency

  28. Rename argument of _outValue()

  29. Rename NodeTag of ExprState