PostgreSQL 9.6的patch，允许用户查看backend的连接信息，如果是SSL连接，输出SSL版本，cipher算法，加密比特位，是否压缩，DNS等信息。
Table 27-6. pg_stat_ssl View
| Column | Type | Description |
|---|---|---|
| pid | integer | Process ID of a backend or WAL sender process |
| ssl | boolean | True if SSL is used on this connection |
| version | text | Version of SSL in use, or NULL if SSL is not in use on this connection |
| cipher | text | Name of SSL cipher in use, or NULL if SSL is not in use on this connection |
| bits | integer | Number of bits in the encryption algorithm used, or NULL if SSL is not used on this connection |
| compression | boolean | True if SSL compression is in use, false if not, or NULL if SSL is not in use on this connection |
| clientdn | text | Distinguished Name (DN) field from the client certificate used, or NULL if no client certificate was supplied or if SSL is not in use on this connection. This field is truncated if the DN field is longer than NAMEDATALEN (64 characters in a standard build) |
The pg_stat_ssl view will contain one row per backend or WAL sender process, showing statistics about SSL usage on this connection. It can be joined to pg_stat_activity or pg_stat_replication on the pid column to get more details about the connection.