SQL Property Graph Queries (SQL/PGQ)

Peter Eisentraut <peter@eisentraut.org>

From: Peter Eisentraut <peter@eisentraut.org>

To: pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2024-02-16T14:53:11Z

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 →

Fix some typos and make small stylistic improvements
- 5282bf535e47 19 (unreleased) landed
Cleanup users and roles in graph_table_rls test
- 040a56be4bcc 19 (unreleased) landed
Dump labels in reproducible order
- c9babbc8816a 19 (unreleased) landed
SQL Property Graph Queries (SQL/PGQ)
- 2f094e7ac691 19 (unreleased) landed
Factor out constructSetOpTargetlist() from transformSetOperationTree()
- 8c2b30487cc7 19 (unreleased) landed
Sort out table_open vs. relation_open in rewriter
- d537f59fbbfc 19 (unreleased) landed
Rename grammar nonterminal to simplify reuse
- 8080f44f96a9 19 (unreleased) landed
Make ecpg parse.pl more robust with braces
- 7f88553ceaca 19 (unreleased) landed
Don't lock partitions pruned by initial pruning
- 525392d5727f 18.0 cited
Remove pg_regex_collation
- 792b2c7e6d92 18.0 cited
Use auxv to check for CRC32 instructions on ARM.
- aac831cafa6f 18.0 cited
Fix inappropriate uses of atol()
- f5a1311fccd2 18.0 cited
Remove unnecessary array object_classes[] in dependency.c
- ef5e2e90859a 17.0 cited

Attachments

v0-0001-WIP-SQL-Property-Graph-Queries-SQL-PGQ.patch (text/plain) patch v0-0001

Here is a prototype implementation of SQL property graph queries
(SQL/PGQ), following SQL:2023.  This was talked about briefly at the
FOSDEM developer meeting, and a few people were interested, so I
wrapped up what I had in progress into a presentable form.

There is some documentation to get started in doc/src/sgml/ddl.sgml
and doc/src/sgml/queries.sgml.

To learn more about this facility, here are some external resources:

* An article about a competing product:
   https://oracle-base.com/articles/23c/sql-property-graphs-and-sql-pgq-23c
   (All the queries in the article work, except the ones using
   vertex_id() and edge_id(), which are non-standard, and the JSON
   examples at the end, which require some of the in-progress JSON
   functionality for PostgreSQL.)

* An academic paper related to another competing product:
   https://www.cidrdb.org/cidr2023/papers/p66-wolde.pdf (The main part
   of this paper discusses advanced functionality that my patch doesn't
   have.)

* A 2019 presentation about graph databases:
   https://www.pgcon.org/2019/schedule/events/1300.en.html (There is
   also a video.)

* (Vik has a recent presentation "Property Graphs: When the Relational
   Model Is Not Enough", but I haven't found the content posted
   online.)

The patch is quite fragile, and treading outside the tested paths will
likely lead to grave misbehavior.  Use with caution.  But I feel that
the general structure is ok, and we just need to fill in the
proverbial few thousand lines of code in the designated areas.