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# 3.8. Replicator

## 3.8.1. Replicator Database Configuration

`[replicator]`

  New in version 1.2.

  `max_replication_retry_count`

    Maximum replication retry count can be a non-negative integer or “infinity”:

        [replicator]
        max_replication_retry_count = 10

  `worker_batch_size`

    With lower batch sizes checkpoints are done more frequently. Lower batch sizes also reduce the total amount of used RAM memory:

        [replicator]
        worker_batch_size = 500

  `worker_processes`

    More worker processes can give higher network throughput but can also imply more disk and network IO:

        [replicator]
        worker_processes = 4

  `http_connections`

    Maximum number of HTTP connections per replication:

        [replicator]
        http_connections = 20

  `connection_timeout`

    HTTP connection timeout per replication. Even for very fast/reliable networks it might need to be increased if a remote database is too busy:

        [replicator]
        connection_timeout = 30000

  `retries_per_request`

    If a request fails, the replicator will retry it up to N times:

        [replicator]
        retries_per_request = 10

  `socket_options`

    Some socket options that might boost performance in some scenarios:

    - `{nodelay, boolean()}`
    - `{sndbuf, integer()}`
    - `{recbuf, integer()}`
    - `{priority, integer()}`

    See the inet Erlang module’s man page for the full list of options:

        [replicator]
        socket_options = [{keepalive, true}, {nodelay, false}]

  `checkpoint_interval`

    New in version 1.6.

    Defines replication checkpoint interval in milliseconds. Replicator will `requests` from the Source database at the specified interval:

        [replicator]
        checkpoint_interval = 5000

    Lower intervals may be useful for frequently changing data, while higher values will lower bandwidth and make fewer requests for infrequently updated databases.

  `use_checkpoints`

    New in version 1.6.

    If `use_checkpoints` is set to `true`, CouchDB will make checkpoints during replication and at the completion of replication. CouchDB can efficiently resume replication from any of these checkpoints:

        [replicator]
        use_checkpoints = true

    Note

    Checkpoints are stored in local documents on both the source and target databases (which requires write access).

    Warning

    Disabling checkpoints is not recommended as CouchDB will scan the Source database’s changes feed from the beginning.

  `cert_file`

    Path to a file containing the user’s certificate:

        [replicator]
        cert_file = /full/path/to/server_cert.pem

  `key_file`

    Path to file containing user’s private PEM encoded key:

        [replicator]
        key_file = /full/path/to/server_key.pem

  `password`

    String containing the user’s password. Only used if the private keyfile is password protected:

        [replicator]
        password = somepassword

  `verify_ssl_certificates`

    Set to true to validate peer certificates:

        [replicator]
        verify_ssl_certificates = false

  `ssl_trusted_certificates_file`

    File containing a list of peer trusted certificates (in the PEM format):

        [replicator]
        ssl_trusted_certificates_file = /etc/ssl/certs/ca-certificates.crt

  `ssl_certificate_max_depth`

    Maximum peer certificate depth (must be set even if certificate validation is off):

        [replicator]
        ssl_certificate_max_depth = 3

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