Very frequent "Too many clients" eventually crashes postmaster

Is there a way to eliminate postmaster crash/core ?

A surge in short-term connections eventually crashes PG on  "no free slots in PMChildFlags array".

Happens on AIX 7.2

=>grep "2020-05-02 08:16" * | grep clients | wc -l
       0
=>grep "2020-05-02 08:17" * | grep clients | wc -l
       0
=>grep "2020-05-02 08:18" * | grep clients | wc -l
     309
=>grep "2020-05-02 08:19" * | grep clients | wc -l
     603
=>grep "2020-05-02 08:20" * | grep clients | wc -l
     288
=>grep "2020-05-02 08:21" * | grep clients | wc -l
     230

2020-05-02 08:21:27.653 CDTFATAL:  no free slots in PMChildFlags array