run in transaction and fix test

Author: Amogh-Bharadwaj

flow/connectors/postgres/pgdump_schema.go

@@ -152,6 +152,16 @@ func buildPsqlArgs(config *protos.PostgresConfig) []string {
 		"-h", config.Host,
 		"-p", strconv.FormatUint(uint64(port), 10),
 		"-d", config.Database,
+		// Wrap the entire dump in a single transaction so partial failures
+		// roll back cleanly (makes the activity safely retryable) and avoid
+		// per-statement autocommit overhead on high-latency links.
+		"--single-transaction",
+		// Without this, psql logs errors to stderr but exits 0, so a half-
+		// applied schema would be reported as success. ON_ERROR_STOP=1 makes
+		// psql exit non-zero on the first failed statement.
+		"-v", "ON_ERROR_STOP=1",
+		// Quiet informational chatter; errors still go to stderr.
+		"--quiet",
 	}
 	if config.User != "" {
 		args = append(args, "-U", config.User)

flow/connectors/postgres/pgdump_schema_test.go

@@ -205,8 +205,13 @@ func TestRunPipeline_ContextCancel(t *testing.T) {
 	requireUnix(t)
 	ctx, cancel := context.WithCancel(t.Context())
 
-	// long-running src that ignores stdin
-	src := exec.CommandContext(ctx, "sh", "-c", "sleep 30")
+	// Use exec'd binaries directly (not `sh -c "..."`). When sh is run with
+	// a single argument, many shells fork a child for the command rather than
+	// exec-replacing themselves. That child inherits sh's stderr fd, and Go's
+	// exec.Wait blocks draining stderr until every fd holder closes it -- so
+	// CommandContext killing sh isn't enough; the child keeps stderr open and
+	// Wait hangs. Using a single-process command avoids the inheritance.
+	src := exec.CommandContext(ctx, "sleep", "30")
 	dst := exec.CommandContext(ctx, "cat")
 	dst.Stdout = &bytes.Buffer{}