Library Version 18.1.40

New Replication Manager Flags
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## New Replication Manager Flags

Prior to the 18.1 release, Berkeley DB's replication manager managed connections using the `select()` call which has a limitation of 1024 open file descriptors. Application working with a very large number of databases, files or network connections and thus consuming more than 1024 file descriptors, were likely to run into this limitation.

Berkeley DB's 18.1 release offers the use of `poll()` and/or `epoll()` in preference to `select()`. In the new implementation, `poll()` is preferred over `select()` because it does not limit the number of open file descriptors. If `epoll()` is available and the number of open file descriptors is greater than 1024, `epoll()` is preferred over `poll()` because it scales better.

No changes are necessary to use the new defaults, but new flags have been added for the user to disable `poll()` and `epoll()` and fall back to `select()`.

### New Parameter Values

- `DB_REPMGR_CONF_DISABLE_POLL`

  A new `flags` parameter value for the `DB_ENV->rep_set_config()` method to indicate that `poll()` should not be used.

- `DB_REPMGR_CONF_DISABLE_EPOLL`

  A new `flags` parameter value for the `DB_ENV->rep_set_config()` method to indicate that `epoll()` should be used (if supported by the target OS). Note that this flag needs to be explicitly specified for `epoll()` to be used by the replication subsystem.

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