PG问题，ERROR: index row requires 8600 bytes, maximum size is 8191，怎么办？

PG问题，ERROR: index row requires 8600 bytes, maximum size is 8191，怎么办？

• hash index
  hash value长度固定

• function index
  func(col), 查询时也使用func(col)

• partial index
  index on tbl (col) where col_length < 8192
  index on tbl (1) where col_length >= 8192
  select x on tbl where … and col_length < 8192 union all … and col_length >= 8192