On Fri, Apr 10, 2026 at 11:36 PM SATYANARAYANA NARLAPURAM <[email protected]> wrote: > > Hi Ashutosh, > > On Fri, Apr 10, 2026 at 9:25 AM Ashutosh Bapat <[email protected]> > wrote: >> >> Hi Satya, >> Thanks for the report and patch. >> >> On Fri, Apr 10, 2026 at 9:12 PM SATYANARAYANA NARLAPURAM >> <[email protected]> wrote: >> > >> > Hi hackers, >> > >> > GRAPH_TABLE COLUMNS expressions that involve collation-dependent functions >> > or operators fail with: >> > >> > ERROR: could not determine which collation to use for upper() function >> > HINT: Use the COLLATE clause to set the collation explicitly. >> > >> > Setup: >> > >> > CREATE TABLE vtx (id int PRIMARY KEY, name text); >> > CREATE TABLE edg (id int PRIMARY KEY, >> > src int REFERENCES vtx(id), >> > dst int REFERENCES vtx(id)); >> > INSERT INTO vtx VALUES (1,'Alice'),(2,'Bob'),(3,'Carol'); >> > INSERT INTO edg VALUES (1,1,2),(2,2,3); >> > >> > CREATE PROPERTY GRAPH g >> > VERTEX TABLES (vtx KEY (id)) >> > EDGE TABLES (edg KEY (id) >> > SOURCE KEY (src) REFERENCES vtx (id) >> > DESTINATION KEY (dst) REFERENCES vtx (id)); >> > >> > postgres=# SELECT * FROM GRAPH_TABLE (g >> > MATCH (a IS vtx)-[e IS edg]->(b IS vtx) COLUMNS (upper(a.name) AS >> > src_upper)); >> > ERROR: could not determine which collation to use for upper() function >> > HINT: Use the COLLATE clause to set the collation explicitly. >> > >> > >> > In transformRangeGraphTable(), the COLUMNS transformation loop calls >> > transformExpr() >> > on each column expression but omits the subsequent >> > assign_expr_collations() call. Both >> > WHERE clause transformation sites in parse_graphtable.c correctly include >> > it. >> > >> > Attached a patch to fix this. >> >> I think the fix is in the right direction. It's better to call >> assign_expr_collation only once on all the columns at the end of loop >> of rgt->columns, just like assign_expr_collation is called on all the >> conditions in WHERE clause once > > > Addressed this in v2 patch. >
If we call assign_expr_collations() on a list, the List expression also gets a collation, which isn't what we want here. We want to assign collations to the individual COLUMNs expression independently. assign_list_collations() is better suited for that. I must say that your earlier patch had got it right in this regard since it was calling assign_expr_collations independently on each COLUMNs expression. However, considering that an all properties reference is replaced by a list of GraphPropertyRefs in place, I think calling assign_list_collations() once on all COLUMNs expressions is a future-proof fix. This is also inline with how collations are assigned to targetlist expressions in a Query. >> >> >> >> Good to see tests also included in the patch. Do we need all three >> queries? Also those queries should be placed near the section "-- test >> collation specified in the expression" and add a query for explicit >> collation in COLUMNs expression. > > > Removed two tests and moved the test. Explicit collate test already exists. I merged this test into an existing test to avoid adding yet another query in the file that has many many queries already. Yes, an explicit collation test is not needed separately. While at it I added comments to explain why we aren't performing en-masse collation assignment on a GraphTable or GraphPathPattern. Please let me know what you think of the attached patch. -- Best Wishes, Ashutosh Bapat
From 7481f0d29508fc656efdd5ff2a692eeea406ac7a Mon Sep 17 00:00:00 2001 From: Ashutosh Bapat <[email protected]> Date: Wed, 15 Apr 2026 16:18:37 +0530 Subject: [PATCH v20260415 1/3] Collation of expressions in GRAPH_TABLE COLUMNS clause GRAPH_TABLE clause is converted into a rangetable entry which is ignored by assign_query_collations(). Hence we assign collations while transforming its parts. Expressions in COLUMNS clause missed that treatment. While at also add comments about collation assignment to the parts of GRAPH_TABLE clause and also fix a small grammar issue. Reported-by: Satyanarayana Narlapuram <[email protected]> Author: Satyanarayana Narlapuram <[email protected]> Author: Ashutosh Bapat <[email protected]> Discussion: https://www.postgresql.org/message-id/cahg+qdc4aaiufysgrwmmpmmrtptq66sghcrpfbwjfzmqnag...@mail.gmail.com --- src/backend/parser/parse_clause.c | 6 ++++++ src/backend/parser/parse_graphtable.c | 12 +++++++++++- src/test/regress/expected/graph_table.out | 8 ++++---- src/test/regress/sql/graph_table.sql | 4 ++-- 4 files changed, 23 insertions(+), 7 deletions(-) diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c index 967eea44f1c..4270c2382c4 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -1003,6 +1003,12 @@ transformRangeGraphTable(ParseState *pstate, RangeGraphTable *rgt) columns = lappend(columns, te); } + /* + * Assign collations to column expressions now since + * assign_query_collations() does not process rangetable entries. + */ + assign_list_collations(pstate, columns); + table_close(rel, NoLock); pstate->p_graph_table_pstate = NULL; diff --git a/src/backend/parser/parse_graphtable.c b/src/backend/parser/parse_graphtable.c index 30ddce5aa9f..87386859a5c 100644 --- a/src/backend/parser/parse_graphtable.c +++ b/src/backend/parser/parse_graphtable.c @@ -252,6 +252,11 @@ transformGraphElementPattern(ParseState *pstate, GraphElementPattern *gep) gep->labelexpr = transformLabelExpr(gpstate, gep->labelexpr); gep->whereClause = transformExpr(pstate, gep->whereClause, EXPR_KIND_WHERE); + + /* + * Assign collations here for the reason mentioned in the prologue of + * transformGraphPattern(). + */ assign_expr_collations(pstate, gep->whereClause); gpstate->cur_gep = NULL; @@ -366,9 +371,14 @@ transformPathPatternList(ParseState *pstate, List *path_pattern) * Transform a GraphPattern. * * A GraphPattern consists of a list of one or more path patterns and an - * optional where clause. Transform them. We use the previously constructure + * optional where clause. Transform them. We use the previously constructed * list of variables in the GraphTableParseState to resolve property references * in the WHERE clause. + * + * Since most parts of the GraphPattern do not require collation assignment, we + * assign collations to the required expressions as they are transformed. This + * avoids the need to traverse the whole GraphPattern again and avoids exposing + * it to assign_expr_collations(). */ Node * transformGraphPattern(ParseState *pstate, GraphPattern *graph_pattern) diff --git a/src/test/regress/expected/graph_table.out b/src/test/regress/expected/graph_table.out index b579e3df635..057f283c43d 100644 --- a/src/test/regress/expected/graph_table.out +++ b/src/test/regress/expected/graph_table.out @@ -652,13 +652,13 @@ SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-(a) COLUMNS (a.vname AS self)); v33 (1 row) --- test collation specified in the expression +-- test explicit and implicit collation assignment INSERT INTO e3_3 VALUES (2003, 2003, 'E331', 10011); -SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b]->(a)-[b]->(a) COLUMNS (a.vname AS self, b.ename AS loop_name)) ORDER BY loop_name COLLATE "C" ASC; +SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b]->(a)-[b]->(a) COLUMNS (upper(a.vname) AS self, b.ename AS loop_name)) ORDER BY loop_name COLLATE "C" ASC; self | loop_name ------+----------- - v33 | E331 - v33 | e331 + V33 | E331 + V33 | e331 (2 rows) SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b IS el2 WHERE b.ename > 'E331' COLLATE "C"]->(a)-[b]->(a) COLUMNS (a.vname AS self, b.ename AS loop_name)); diff --git a/src/test/regress/sql/graph_table.sql b/src/test/regress/sql/graph_table.sql index 4ff98817420..278064818ff 100644 --- a/src/test/regress/sql/graph_table.sql +++ b/src/test/regress/sql/graph_table.sql @@ -394,9 +394,9 @@ SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b]->(c)-[b]->(d) COLUMNS (a.vname AS an SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[c]-(a) COLUMNS (a.vname AS self, c.ename AS loop_name)); SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-(a) COLUMNS (a.vname AS self)); --- test collation specified in the expression +-- test explicit and implicit collation assignment INSERT INTO e3_3 VALUES (2003, 2003, 'E331', 10011); -SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b]->(a)-[b]->(a) COLUMNS (a.vname AS self, b.ename AS loop_name)) ORDER BY loop_name COLLATE "C" ASC; +SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b]->(a)-[b]->(a) COLUMNS (upper(a.vname) AS self, b.ename AS loop_name)) ORDER BY loop_name COLLATE "C" ASC; SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b IS el2 WHERE b.ename > 'E331' COLLATE "C"]->(a)-[b]->(a) COLUMNS (a.vname AS self, b.ename AS loop_name)); SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b]->(a)-[b]->(a) WHERE b.ename > 'E331' COLLATE "C" COLUMNS (a.vname AS self, b.ename AS loop_name)); SELECT * FROM GRAPH_TABLE (g1 MATCH (a)-[b]->(a)-[b]->(a) COLUMNS (a.vname AS self, b.ename AS loop_name)) WHERE loop_name > 'E331' COLLATE "C"; base-commit: f30d0c720f2ec979ab1b5b44b1f9f201d6efdf8c -- 2.34.1
