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[PATCH] Resolve unknown-type literals in GRAPH_TABLE COLUMNS

  • Jump to comment-1
    SATYANARAYANA NARLAPURAM<satyanarlapuram@gmail.com>
    Apr 25, 2026, 7:53 PM UTC
    Hi hackers,
    transformRangeGraphTable() calls transformExpr() and
    assignlistcollations() for COLUMNS expressions but missed calling
    resolveTargetListUnknowns(). As a result, literals such as 'val1'
    in a COLUMNS clause retained type "unknown", causing failures with
    ORDER BY, UNION, and output conversions.
    Fix by calling resolveTargetListUnknowns() on the columns target
    list right after assignlistcollations(), similar to SELECT target lists
    in
    transformSelectStmt().
    Attached a patch to fix this, which also includes test cases to reproduce.
    Thanks,
    Satya
    View in PostgreSQL Archives →
    • Jump to comment-1
      Junwang Zhao<zhjwpku@gmail.com>
      Apr 26, 2026, 3:10 PM UTC
      Hi SATYANARAYANA,
      On Sun, Apr 26, 2026 at 3:53 AM SATYANARAYANA NARLAPURAM
      <satyanarlapuram@gmail.com> wrote:

      Hi hackers,

      transformRangeGraphTable() calls transformExpr() and
      assignlistcollations() for COLUMNS expressions but missed calling
      resolveTargetListUnknowns(). As a result, literals such as 'val1'
      in a COLUMNS clause retained type "unknown", causing failures with
      ORDER BY, UNION, and output conversions.

      Fix by calling resolveTargetListUnknowns() on the columns target
      list right after assignlistcollations(), similar to SELECT target lists in
      transformSelectStmt().

      Attached a patch to fix this, which also includes test cases to reproduce.
      I can reproduce this and the patch fixes it.
      One question: why is resolveTargetListUnknowns called after
      assignlistcollations?
      I'm asking because in transformSelectStmt, resolveTargetListUnknowns
      is invoked before assignquerycollations. It might not matter, but keeping
      the order consistent would be good for readers.


      Thanks,
      Satya

      --
      Regards
      Junwang Zhao
      View in PostgreSQL Archives →
      • Jump to comment-1
        SATYANARAYANA NARLAPURAM<satyanarlapuram@gmail.com>
        Apr 27, 2026, 6:09 AM UTC
        Hi,
        On Sun, Apr 26, 2026 at 8:10 AM Junwang Zhao <zhjwpku@gmail.com> wrote:
        Hi SATYANARAYANA,

        On Sun, Apr 26, 2026 at 3:53 AM SATYANARAYANA NARLAPURAM
        <satyanarlapuram@gmail.com> wrote:

        Hi hackers,

        transformRangeGraphTable() calls transformExpr() and
        assignlistcollations() for COLUMNS expressions but missed calling
        resolveTargetListUnknowns(). As a result, literals such as 'val1'
        in a COLUMNS clause retained type "unknown", causing failures with
        ORDER BY, UNION, and output conversions.

        Fix by calling resolveTargetListUnknowns() on the columns target
        list right after assignlistcollations(), similar to SELECT target
        lists in
        transformSelectStmt().

        Attached a patch to fix this, which also includes test cases to
        reproduce.

        I can reproduce this and the patch fixes it.

        One question: why is resolveTargetListUnknowns called after
        assignlistcollations?

        I'm asking because in transformSelectStmt, resolveTargetListUnknowns
        is invoked before assignquerycollations. It might not matter, but keeping
        the order consistent would be good for readers.
        Updated the patch. It should be before.
        Thanks,
        Satya
        View in PostgreSQL Archives →
        • Jump to comment-1
          Ashutosh Bapat<ashutosh.bapat.oss@gmail.com>
          Apr 29, 2026, 2:10 PM UTC
          On Mon, Apr 27, 2026 at 11:34 AM SATYANARAYANA NARLAPURAM
          <satyanarlapuram@gmail.com> wrote:

          Hi,
          On Sun, Apr 26, 2026 at 8:10 AM Junwang Zhao <zhjwpku@gmail.com> wrote:

          Hi SATYANARAYANA,

          On Sun, Apr 26, 2026 at 3:53 AM SATYANARAYANA NARLAPURAM
          <satyanarlapuram@gmail.com> wrote:

          Hi hackers,

          transformRangeGraphTable() calls transformExpr() and
          assignlistcollations() for COLUMNS expressions but missed calling
          resolveTargetListUnknowns(). As a result, literals such as 'val1'
          in a COLUMNS clause retained type "unknown", causing failures with
          ORDER BY, UNION, and output conversions.

          Fix by calling resolveTargetListUnknowns() on the columns target
          list right after assignlistcollations(), similar to SELECT target lists in
          transformSelectStmt().

          Attached a patch to fix this, which also includes test cases to reproduce.

          I can reproduce this and the patch fixes it.

          One question: why is resolveTargetListUnknowns called after
          assignlistcollations?

          I'm asking because in transformSelectStmt, resolveTargetListUnknowns
          is invoked before assignquerycollations. It might not matter, but keeping
          the order consistent would be good for readers.


          Updated the patch. It should be before.
          Do we really need a test for ORDER BY on a literal column? I replaced
          all the test queries with a single one which covers all the scenarios
          covered by those queries.
          The patch needed to consider pstate->presolveunknowns. Unknown
          literals are not resolved as text always. See the test query.
          --
          Best Wishes,
          Ashutosh Bapat
          View in PostgreSQL Archives →