multica-ai/multica · error

inspect concurrent index %q: %w

Error message

inspect concurrent index %q: %w

What it means

The migrate tool's catalog probe failed: it queries pg_class/pg_namespace/pg_index via to_regclass($1) to decide whether a concurrently-built index exists and is valid before retrying a failed CREATE INDEX CONCURRENTLY migration. A query error here means the catalog read itself failed — connection loss, cancellation, or permissions on system catalogs.

Source

Thrown at server/cmd/migrate/main.go:177

// Without this guard, CREATE INDEX ... IF NOT EXISTS would treat the leftover
// relation as success and allow a later migration to drop the still-valid old
// index. Non-index relations fail closed instead of being dropped implicitly.
func cleanupInvalidConcurrentIndexHook(indexRegclass string) preMigrationHook {
	return func(ctx context.Context, pool *pgxpool.Pool) error {
		var schemaName, relationName string
		var isIndex, isValid bool
		err := pool.QueryRow(ctx, `
			SELECT n.nspname, c.relname, c.relkind = 'i', COALESCE(i.indisvalid, FALSE)
			FROM pg_class c
			JOIN pg_namespace n ON n.oid = c.relnamespace
			LEFT JOIN pg_index i ON i.indexrelid = c.oid
			WHERE c.oid = to_regclass($1)
		`, indexRegclass).Scan(&schemaName, &relationName, &isIndex, &isValid)
		if errors.Is(err, pgx.ErrNoRows) {
			return nil
		}
		if err != nil {
			return fmt.Errorf("inspect concurrent index %q: %w", indexRegclass, err)
		}
		if !isIndex {
			return fmt.Errorf("relation %q exists but is not an index", indexRegclass)
		}
		if isValid {
			return nil
		}

		qualifiedName := pgx.Identifier{schemaName, relationName}.Sanitize()
		if _, err := pool.Exec(ctx, "DROP INDEX CONCURRENTLY IF EXISTS "+qualifiedName); err != nil {
			return fmt.Errorf("drop invalid concurrent index %s: %w", qualifiedName, err)
		}
		slog.Warn("removed invalid index before migration retry", "index", qualifiedName)
		return nil
	}
}

func runTaskUsageHourlyHook(ctx context.Context, pool *pgxpool.Pool) error {

View on GitHub (pinned to 2c0912b6ec)

Solutions

1. Re-run `migrate up` — the advisory lock and per-version EXISTS checks make it resumable
2. Check the wrapped error: if auth-related, grant the migration role read on system catalogs or use a privileged role
3. Verify the index name passed in the hook is a valid qualified identifier (schema.index)

if err != nil {
    return fmt.Errorf("inspect concurrent index %q: %w", indexRegclass, err)
}

When it happens

Trigger: Connection dropped while inspecting; ctx cancelled; indexRegclass malformed enough to break parameter binding; running as a role denied SELECT on pg_class.

Common situations: Rare in practice; most often a transient network blip or an operator-killed migration run at exactly this step.

Related errors

• relation %q exists but is not an index
• drop invalid concurrent index %s: %w
• task_usage_hourly pre-103 hook: %w
• attribution strict-constraint pre-198 hook: %w
• invalid schema migrations table %q: %w

AI-assisted analysis of multica-ai/multica@2c0912b6ec (2026-08-15). Data as JSON: /api/errors/92f8ee08e4dd6f51. Report an issue: GitHub.