A.56. Release 4.2.21

Remove pg_basebackup from the sample follow primary script. (Bo Peng)

If pg_rewind fails, the safest way for users is to recover manually.

Fix per_node_error_log() error message that is printed with two colons. (Bo Peng)

Patch is created by Umar Hayat.

Fix pool_signal. (Tatsuo Ishii)

Previously pool_signal did not set SA_RESTART flag. Thus any system calls interrupted by a signal does not restart. Some of our code are prepared so that they restart if a system call is interrupted by a signal. But not sure all places are prepared too. So add the flag. Note, PostgreSQL always uses the flag.

Fixed an issue where pg_md5 and pg_enc would not update the password file if a file other than the default value was specified in the pool_passwd parameter. (Bo Peng)

This issue is reported by Sadhuprasad Patro.

Fix several query cache bugs in streaming replication mode. (Tatsuo Ishii)

• When query cache is enabled and an execute message is sent from frontend, Pgpool-II injects query cache data into backend message buffer if query cache data is available. But it was possible that the cached message is inserted at inappropriate position and Pgpool-II mistakenly raised "kind mismatch" error.

• If query cache is enabled and query is operated in extended query mode and pgpool is running in streaming replication mode, an execute message could return incorrect results.

• Another trouble is when multiple execute messages are sent consecutively. In this case Pgpool-II returned exactly the same results from query cache for each execute message. This is wrong since the second or subsequent executes should return 0 rows.

  Discussion: [pgpool-hackers: 4547] Bug in query cache

Enhance client authentication chapter. (Tatsuo Ishii)

Add intro about pool_passwd. Previously there was only description on pool_hba.conf in the overview page. A general guide to pool_passwd will help users to understand this chapter.

Stabilize 032.dml_adaptive_loadbalance (Tatsuo Ishii)