| Type: | integer |
| Default: | 10 |
| Min: | 0 |
| Max: | 262143 |
| Context: | postmaster |
| Restart: | true |
| Since: | 9.4 |
Specifies the maximum number of replication slots (see streaming-replication-slots) that the server can support. The default is 10. This parameter can only be set at server start. Setting it to a lower value than the number of currently existing replication slots will prevent the server from starting. Also, wal_level must be set to replica or higher to allow replication slots to be used.
Note that this parameter also applies on the subscriber side, but with a different meaning.
Recommendations
Set to twice as many replicas as you ever expect to have.