Horton

Re: SQL Property Graph Queries (SQL/PGQ)

Florents Tselai <florents.tselai@gmail.com>

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From: Florents Tselai <florents.tselai@gmail.com>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>, Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Date: 2024-07-04T08:19:46Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Fix some typos and make small stylistic improvements

  2. Cleanup users and roles in graph_table_rls test

  3. Dump labels in reproducible order

  4. SQL Property Graph Queries (SQL/PGQ)

  5. Factor out constructSetOpTargetlist() from transformSetOperationTree()

  6. Sort out table_open vs. relation_open in rewriter

  7. Rename grammar nonterminal to simplify reuse

  8. Make ecpg parse.pl more robust with braces

  9. Don't lock partitions pruned by initial pruning

  10. Remove pg_regex_collation

  11. Use auxv to check for CRC32 instructions on ARM.

  12. Fix inappropriate uses of atol()

  13. Remove unnecessary array object_classes[] in dependency.c

In the ddl.sgml, I’d swap the first two paragraphs.
I find the first one a bit confusing as-is. As far as I can tell, it’s an implementation detail.
The first paragraph should answer, “I have some data modeled as a graph G=(V, E). Can Postgres help me?”.

Then, introducing property graphs makes more sense. 

I'd also use the examples and fake data in `graph_table.sql` in ddl/queries.sgml).
I was bummed that that copy-pasting didn't work as is.
I’d keep explaining how a graph query translates to a relational one later in the page.

As for the implementation, I can’t have an opinion yet,
but for those not familiar, Apache Age uses a slightly different approach
that mimics jsonpath (parses a sublanguage expression into an internal execution engine etc.).
However, the standard requires mapping this to the relational model, which makes sense for core Postgres.


> On 27 Jun 2024, at 3:31 PM, Peter Eisentraut <peter@eisentraut.org> wrote:
> 
> Here is a new version of this patch.  I have been working together with Ashutosh on this.  While the version 0 was more of a fragile demo, this version 1 has a fairly complete minimal feature set and should be useful for playing around with.  We do have a long list of various internal bits that still need to be fixed or revised or looked at again, so there is by no means a claim that everything is completed.
> 
> Documentation to get started is included (ddl.sgml and queries.sgml). (Of course, feedback on the getting-started documentation would be most welcome.)
> <v1-0001-WIP-SQL-Property-Graph-Queries-SQL-PGQ.patch>