database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-16 15:02:33 +03:00
Code Activity

Disallow generated columns in COPY WHERE clause

Browse Source 
Stored generated columns are not yet computed when the filtering
happens, so we need to prohibit them to avoid incorrect behavior.

Virtual generated columns currently error out ("unexpected virtual
generated column reference").  They could probably work if we expand
them in the right place, but for now let's keep them consistent with
the stored variant.  This doesn't change the behavior, it only gives a
nicer error message.

Co-authored-by: jian he <jian.universality@gmail.com>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CACJufxHb8YPQ095R_pYDr77W9XKNaXg5Rzy-WP525mkq+hRM3g@mail.gmail.com
This commit is contained in:
Peter Eisentraut
2025-11-06 11:52:47 +01:00
parent aa9c5fd3e3
commit aa606b9316
5 changed files with 59 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

39
src/backend/commands/copy.c
View File

@@ -133,6 +133,9 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
if (stmt->whereClause)
{
Bitmapset *expr_attrs = NULL;
int i;
/* add nsitem to query namespace */
addNSItemToQuery(pstate, nsitem, false, true, true);
@@ -145,6 +148,42 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
/* we have to fix its collations too */
assign_expr_collations(pstate, whereClause);
/*
* Examine all the columns in the WHERE clause expression. When
* the whole-row reference is present, examine all the columns of
* the table.
*/
pull_varattnos(whereClause, 1, &expr_attrs);
if (bms_is_member(0 - FirstLowInvalidHeapAttributeNumber, expr_attrs))
{
expr_attrs = bms_add_range(expr_attrs,
1 - FirstLowInvalidHeapAttributeNumber,
RelationGetNumberOfAttributes(rel) - FirstLowInvalidHeapAttributeNumber);
expr_attrs = bms_del_member(expr_attrs, 0 - FirstLowInvalidHeapAttributeNumber);
}
i = -1;
while ((i = bms_next_member(expr_attrs, i)) >= 0)
{
AttrNumber attno = i + FirstLowInvalidHeapAttributeNumber;
Assert(attno != 0);
/*
* Prohibit generated columns in the WHERE clause. Stored
* generated columns are not yet computed when the filtering
* happens. Virtual generated columns could probably work (we
* would need to expand them somewhere around here), but for
* now we keep them consistent with the stored variant.
*/
if (TupleDescAttr(RelationGetDescr(rel), attno - 1)->attgenerated)
ereport(ERROR,
errcode(ERRCODE_INVALID_COLUMN_REFERENCE),
errmsg("generated columns are not supported in COPY FROM WHERE conditions"),
errdetail("Column \"%s\" is a generated column.",
get_attname(RelationGetRelid(rel), attno, false)));
}
whereClause = eval_const_expressions(NULL, whereClause);
whereClause = (Node *) canonicalize_qual((Expr *) whereClause, false);