Re: SQL Property Graph Queries (SQL/PGQ)

Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

From: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

To: Imran Zaheer <imran.zhir@gmail.com>

Cc: Peter Eisentraut <peter@eisentraut.org>, pgsql-hackers <pgsql-hackers@postgresql.org>

Date: 2024-08-05T13:12:46Z

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 →

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

Hi Imran,

On Sun, Aug 4, 2024 at 12:32 PM Imran Zaheer <imran.zhir@gmail.com> wrote:
>
> Hi
> I am attaching a new patch for a minor feature addition.
>
> - Adding support for 'Labels and properties: EXCEPT list'

Do you intend to support EXCEPT in the label expression as well or
just properties?

>
> Please let me know if something is missing.

I think the code changes are in the right place. I didn't review the
patch thoroughly. But here are some comments and some advice.

Please do not top-post on hackers.

Always sent the whole patchset. Otherwise, CI bot gets confused. It
doesn't pick up patchset from the previous emails.

About the functionality: It's not clear to me whether an EXCEPT should
be applicable only at the time of property graph creation or it should
be applicable always. I.e. when a property graph is dumped, should it
have EXCEPT in it or have a list of columns surviving except list?
What if a column in except list is dropped after creating a property
graph?

Some comments on the code
1. You could use list_member() in insert_property_records() to check
whether a given column is in the list of exceptions after you have
enveloped in String node.
2. The SELECT with GRAPH_TABLE queries are tested in graph_table.sql.
We don't include those in create_property_graph.sql
3. Instead of creating a new property graph in the test, you may
modify one of the existing property graphs to have a label with except
list and then query it.

We are aiming a minimal set of features in the first version. I will
let Peter E. decide whether to consider this as minimal set feature or
not. The feature looks useful to me.

-- 
Best Wishes,
Ashutosh Bapat