diff options
Diffstat (limited to 'src/backend')
| -rw-r--r-- | src/backend/commands/copy.c | 45 |
1 files changed, 27 insertions, 18 deletions
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c index 8904676609d..47dd3accafe 100644 --- a/src/backend/commands/copy.c +++ b/src/backend/commands/copy.c @@ -896,8 +896,12 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed) target->val = (Node *) cr; target->location = 1; - /* Build FROM clause */ - from = stmt->relation; + /* + * Build RangeVar for from clause, fully qualified based on the + * relation which we have opened and locked. + */ + from = makeRangeVar(get_namespace_name(RelationGetNamespace(rel)), + RelationGetRelationName(rel), -1); /* Build query */ select = makeNode(SelectStmt); @@ -906,8 +910,13 @@ DoCopy(const CopyStmt *stmt, const char *queryString, uint64 *processed) query = (Node *) select; - /* Close the handle to the relation as it is no longer needed. */ - heap_close(rel, (is_from ? RowExclusiveLock : AccessShareLock)); + /* + * Close the relation for now, but keep the lock on it to prevent + * changes between now and when we start the query-based COPY. + * + * We'll reopen it later as part of the query-based COPY. + */ + heap_close(rel, NoLock); rel = NULL; } } @@ -1407,25 +1416,25 @@ BeginCopy(bool is_from, plan = planner(query, 0, NULL); /* - * If we were passed in a relid, make sure we got the same one back - * after planning out the query. It's possible that it changed - * between when we checked the policies on the table and decided to - * use a query and now. + * With row level security and a user using "COPY relation TO", we + * have to convert the "COPY relation TO" to a query-based COPY (eg: + * "COPY (SELECT * FROM relation) TO"), to allow the rewriter to add + * in any RLS clauses. + * + * When this happens, we are passed in the relid of the originally + * found relation (which we have locked). As the planner will look + * up the relation again, we double-check here to make sure it found + * the same one that we have locked. */ if (queryRelId != InvalidOid) { - Oid relid = linitial_oid(plan->relationOids); - /* - * There should only be one relationOid in this case, since we - * will only get here when we have changed the command for the - * user from a "COPY relation TO" to "COPY (SELECT * FROM - * relation) TO", to allow row level security policies to be - * applied. + * Note that with RLS involved there may be multiple relations, + * and while the one we need is almost certainly first, we don't + * make any guarantees of that in the planner, so check the whole + * list and make sure we find the original relation. */ - Assert(list_length(plan->relationOids) == 1); - - if (relid != queryRelId) + if (!list_member_oid(plan->relationOids, queryRelId)) ereport(ERROR, (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE), errmsg("relation referenced by COPY statement has changed"))); |