8ce749f8f6
The COLUMNS list of a GRAPH_TABLE query is parsed as an ordinary select
target list, which permits aggregate functions, window functions, and
set-returning functions. GRAPH_TABLE has no machinery to evaluate them,
though: the rewriter copies the COLUMNS target list verbatim into a
freshly built subquery whose hasAggs/hasWindowFuncs/hasTargetSRFs flags
are never set, so the planner builds no Agg/WindowAgg node (and no SRF
expansion) and the Aggref/WindowFunc/SRF reaches the executor. This
triggers an assertion failure ("ecxt_aggvalues != NULL"), or "Aggref
found in non-Agg plan node" on a non-assert build, for otherwise
parser-accepted SQL such as
SELECT max(c) FROM GRAPH_TABLE
(g MATCH (x IS v) COLUMNS (count(*) AS c));
Reject these constructs in transformRangeGraphTable() the same way
subqueries are already handled: save and clear pstate->p_hasAggs,
p_hasWindowFuncs, and p_hasTargetSRFs around the transformation of the
COLUMNS list, and raise a "not supported" error if any of them got set.
This is deliberately a blanket prohibition for now. Once quantified
element patterns such as (a)->{1,5} are supported, aggregates over
property references of higher degree (e.g. count(a) or sum(a.val)) can
be allowed; at that point the check will need to inspect the aggregate
arguments rather than reject all aggregates outright.
Author: Ewan Young <kdbase.hack@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAON2xHOYAmYLkB2jGi6g77d6Fqv8YgOrfV-riQVf0K_7AdxD3w@mail.gmail.com
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/19/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/19/installation.html.
The latest version of this software, and related software, may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.