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| author | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2022-08-12 12:05:50 +0200 |
|---|---|---|
| committer | Alvaro Herrera <alvherre@alvh.no-ip.org> | 2022-08-12 12:05:50 +0200 |
| commit | 455d254d22665eb7af3b714435f3fecc63696cc7 (patch) | |
| tree | 3fed7037832968b7a77391721e86f1d1622778f1 | |
| parent | e1878cf94134429bf951b41ed523363c2fa2d6b4 (diff) | |
Reject MERGE in CTEs and COPY
The grammar added for MERGE inadvertently made it accepted syntax in
places that were not prepared to deal with it -- namely COPY and inside
CTEs, but invoking these things with MERGE currently causes assertion
failures or weird misbehavior in non-assertion builds. Protect those
places by checking for it explicitly until somebody decides to implement
it.
Reported-by: Alexey Borzov <borz_off@cs.msu.su>
Discussion: https://postgr.es/m/17579-82482cd7b267b862@postgresql.org
| -rw-r--r-- | src/backend/commands/copy.c | 6 | ||||
| -rw-r--r-- | src/backend/parser/parse_cte.c | 7 | ||||
| -rw-r--r-- | src/test/regress/expected/merge.out | 14 | ||||
| -rw-r--r-- | src/test/regress/sql/merge.sql | 10 |
4 files changed, 37 insertions, 0 deletions
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c index e2870e3c11c..2e90563333e 100644 --- a/src/backend/commands/copy.c +++ b/src/backend/commands/copy.c @@ -273,6 +273,12 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt, { Assert(stmt->query); + /* MERGE is allowed by parser, but unimplemented. Reject for now */ + if (IsA(stmt->query, MergeStmt)) + ereport(ERROR, + errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("MERGE not supported in COPY")); + query = makeNode(RawStmt); query->stmt = stmt->query; query->stmt_location = stmt_location; diff --git a/src/backend/parser/parse_cte.c b/src/backend/parser/parse_cte.c index efb4af706e1..8fc86586085 100644 --- a/src/backend/parser/parse_cte.c +++ b/src/backend/parser/parse_cte.c @@ -126,6 +126,13 @@ transformWithClause(ParseState *pstate, WithClause *withClause) CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc); ListCell *rest; + /* MERGE is allowed by parser, but unimplemented. Reject for now */ + if (IsA(cte->ctequery, MergeStmt)) + ereport(ERROR, + errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("MERGE not supported in WITH query"), + parser_errposition(pstate, cte->location)); + for_each_cell(rest, withClause->ctes, lnext(withClause->ctes, lc)) { CommonTableExpr *cte2 = (CommonTableExpr *) lfirst(rest); diff --git a/src/test/regress/expected/merge.out b/src/test/regress/expected/merge.out index af670e28e7f..729ae2eb065 100644 --- a/src/test/regress/expected/merge.out +++ b/src/test/regress/expected/merge.out @@ -123,6 +123,20 @@ ON tid = tid WHEN MATCHED THEN DO NOTHING; ERROR: name "target" specified more than once DETAIL: The name is used both as MERGE target table and data source. +-- used in a CTE +WITH foo AS ( + MERGE INTO target USING source ON (true) + WHEN MATCHED THEN DELETE +) SELECT * FROM foo; +ERROR: MERGE not supported in WITH query +LINE 1: WITH foo AS ( + ^ +-- used in COPY +COPY ( + MERGE INTO target USING source ON (true) + WHEN MATCHED THEN DELETE +) TO stdout; +ERROR: MERGE not supported in COPY -- unsupported relation types -- view CREATE VIEW tv AS SELECT * FROM target; diff --git a/src/test/regress/sql/merge.sql b/src/test/regress/sql/merge.sql index afeb212f3c8..e0c450736bd 100644 --- a/src/test/regress/sql/merge.sql +++ b/src/test/regress/sql/merge.sql @@ -88,6 +88,16 @@ MERGE INTO target USING target ON tid = tid WHEN MATCHED THEN DO NOTHING; +-- used in a CTE +WITH foo AS ( + MERGE INTO target USING source ON (true) + WHEN MATCHED THEN DELETE +) SELECT * FROM foo; +-- used in COPY +COPY ( + MERGE INTO target USING source ON (true) + WHEN MATCHED THEN DELETE +) TO stdout; -- unsupported relation types -- view |