Postgresql 中文操作指南

70.6. Limitations #

GIN 假设可索引运算符是严格的。这意味着 extractValue 根本不会在空项值上被调用（而是自动创建一个占位索引项），并且 extractQuery 也不会在空查询值上被调用（而是预设查询不可满足）。但是，请注意，空键值（如果包含在非空复合项或查询值内）是受支持的。

GIN assumes that indexable operators are strict. This means that extractValue will not be called at all on a null item value (instead, a placeholder index entry is created automatically), and extractQuery will not be called on a null query value either (instead, the query is presumed to be unsatisfiable). Note however that null key values contained within a non-null composite item or query value are supported.