Constant INTROSPECT_INDEXES_SQL 

pub const INTROSPECT_INDEXES_SQL: &str = "\
    SELECT i.relname as index_name, \
           ix.indisunique as is_unique, \
           array_agg(a.attname ORDER BY array_position(ix.indkey, a.attnum)) as columns \
    FROM pg_index ix \
    JOIN pg_class t ON t.oid = ix.indrelid \
    JOIN pg_class i ON i.oid = ix.indexrelid \
    JOIN pg_attribute a ON a.attrelid = t.oid AND a.attnum = ANY(ix.indkey) \
    JOIN pg_namespace n ON n.oid = t.relnamespace \
    WHERE n.nspname = 'public' \
      AND t.relname = $1 \
      AND NOT ix.indisprimary \
    GROUP BY i.relname, ix.indisunique \
    ORDER BY i.relname";

SQL to list indexes for a given table. Use with parameter: table_name.