Error for COPY FROM ... on_error, log_verbosity with Citus tables (#7811)

PG17 added the new ON_ERROR option for COPY FROM. When this option is
specified, COPY skips soft errors and
continues copying.
Relevant PG commits:
-- https://github.com/postgres/postgres/commit/9e2d87011
-- https://github.com/postgres/postgres/commit/b725b7eec

I tried it locally with Citus tables.
Without further implementation, it doesn't work correctly.
Therefore, we error out for now, and add it to future work.

PG17 also added log_verbosity option, which controls the
 amount of messages emitted during processing. This is
 currently used in COPY FROM when ON_ERROR option is set to
 ignore. Therefore, we error out for this option as well.
Relevant PG17 commit:
https://github.com/postgres/postgres/commit/f5a227895

src/backend/distributed/commands/multi_copy.c

@@ -301,6 +301,7 @@ static SelectStmt * CitusCopySelect(CopyStmt *copyStatement);
 static void CitusCopyTo(CopyStmt *copyStatement, QueryCompletion *completionTag);
 static int64 ForwardCopyDataFromConnection(CopyOutState copyOutState,
 										   MultiConnection *connection);
+static void ErrorIfCopyHasOnErrorLogVerbosity(CopyStmt *copyStatement);
 
 /* Private functions copied and adapted from copy.c in PostgreSQL */
 static void SendCopyBegin(CopyOutState cstate);
@@ -2824,6 +2825,44 @@ CopyStatementHasFormat(CopyStmt *copyStatement, char *formatName)
 }
 
 
+/*
+ * ErrorIfCopyHasOnErrorLogVerbosity errors out if the COPY statement
+ * has on_error option or log_verbosity option specified
+ */
+static void
+ErrorIfCopyHasOnErrorLogVerbosity(CopyStmt *copyStatement)
+{
+#if PG_VERSION_NUM >= PG_VERSION_17
+	bool log_verbosity = false;
+	foreach_ptr(DefElem, option, copyStatement->options)
+	{
+		if (strcmp(option->defname, "on_error") == 0)
+		{
+			ereport(ERROR, (errmsg(
+								"Citus does not support COPY FROM with ON_ERROR option.")));
+		}
+		else if (strcmp(option->defname, "log_verbosity") == 0)
+		{
+			log_verbosity = true;
+		}
+	}
+
+	/*
+	 * Given that log_verbosity is currently used in COPY FROM
+	 * when ON_ERROR option is set to ignore, it makes more
+	 * sense to error out for ON_ERROR option first. For this reason,
+	 * we don't error out in the previous loop directly.
+	 * Relevant PG17 commit: https://github.com/postgres/postgres/commit/f5a227895
+	 */
+	if (log_verbosity)
+	{
+		ereport(ERROR, (errmsg(
+							"Citus does not support COPY FROM with LOG_VERBOSITY option.")));
+	}
+#endif
+}
+
+
 /*
  * ErrorIfMergeInCopy Raises an exception if the MERGE is called in the COPY
  * where Citus tables are involved, as we don't support this yet
@@ -2926,6 +2965,8 @@ ProcessCopyStmt(CopyStmt *copyStatement, QueryCompletion *completionTag, const
 										"Citus does not support COPY FROM with WHERE")));
 				}
 
+				ErrorIfCopyHasOnErrorLogVerbosity(copyStatement);
+
 				/* check permissions, we're bypassing postgres' normal checks */
 				CheckCopyPermissions(copyStatement);
 				CitusCopyFrom(copyStatement, completionTag);

src/test/regress/expected/pg17.out

@@ -1215,6 +1215,29 @@ btree, for table "pg17.tbl"
 btree, for table "pg17.tbl_25122024"
 
 -- End of testing SET STATISTICS DEFAULT
+-- COPY ON_ERROR option
+-- Error out for Citus tables because we don't support it yet
+-- Relevant PG17 commits:
+-- https://github.com/postgres/postgres/commit/9e2d87011
+-- https://github.com/postgres/postgres/commit/b725b7eec
+CREATE TABLE check_ign_err (n int, m int[], k int);
+SELECT create_distributed_table('check_ign_err', 'n');
+ create_distributed_table
+---------------------------------------------------------------------
+
+(1 row)
+
+COPY check_ign_err FROM STDIN WITH (on_error stop);
+ERROR:  Citus does not support COPY FROM with ON_ERROR option.
+COPY check_ign_err FROM STDIN WITH (ON_ERROR ignore);
+ERROR:  Citus does not support COPY FROM with ON_ERROR option.
+COPY check_ign_err FROM STDIN WITH (on_error ignore, log_verbosity verbose);
+ERROR:  Citus does not support COPY FROM with ON_ERROR option.
+COPY check_ign_err FROM STDIN WITH (log_verbosity verbose, on_error ignore);
+ERROR:  Citus does not support COPY FROM with ON_ERROR option.
+COPY check_ign_err FROM STDIN WITH (log_verbosity verbose);
+ERROR:  Citus does not support COPY FROM with LOG_VERBOSITY option.
+-- End of Test for COPY ON_ERROR option
 \set VERBOSITY terse
 SET client_min_messages TO WARNING;
 DROP SCHEMA pg17 CASCADE;

src/test/regress/sql/pg17.sql

@@ -604,6 +604,23 @@ ALTER INDEX tbl_idx ALTER COLUMN 2 SET STATISTICS -1;
 
 -- End of testing SET STATISTICS DEFAULT
 
+-- COPY ON_ERROR option
+-- Error out for Citus tables because we don't support it yet
+-- Relevant PG17 commits:
+-- https://github.com/postgres/postgres/commit/9e2d87011
+-- https://github.com/postgres/postgres/commit/b725b7eec
+
+CREATE TABLE check_ign_err (n int, m int[], k int);
+SELECT create_distributed_table('check_ign_err', 'n');
+
+COPY check_ign_err FROM STDIN WITH (on_error stop);
+COPY check_ign_err FROM STDIN WITH (ON_ERROR ignore);
+COPY check_ign_err FROM STDIN WITH (on_error ignore, log_verbosity verbose);
+COPY check_ign_err FROM STDIN WITH (log_verbosity verbose, on_error ignore);
+COPY check_ign_err FROM STDIN WITH (log_verbosity verbose);
+
+-- End of Test for COPY ON_ERROR option
+
 \set VERBOSITY terse
 SET client_min_messages TO WARNING;
 DROP SCHEMA pg17 CASCADE;