3.16. Miscellaneous Parameters

3.16.1. Configuration of Attachment Storage

[attachments]

compression_level

Defines zlib compression level for the attachments from 1 (lowest, fastest) to 9 (highest, slowest). A value of 0 disables compression:

[attachments]
compression_level = 8

compressible_types

Since compression is ineffective for some types of files, it is possible to let CouchDB compress only some types of attachments, specified by their MIME type:

[attachments]
compressible_types = text/*, application/javascript, application/json, application/xml

3.16.2. Statistic Calculation

[stats]

interval

Interval between gathering statistics in seconds:

[stats]
interval = 10

3.16.3. UUIDs Configuration

[uuids]

algorithm

Changed in version 1.3: Added utc_id algorithm.

Changed in version 3.5.1: Added uuid_v7 algorithm.

Changed in version 3.6: Added uuid_v4 algorithm and uuid_v7 algorithm became the default.

CouchDB provides various algorithms to generate the UUID values that are used for document _id’s by default:

[uuids]
algorithm = sequential

Available algorithms:

random: 128 bits of random awesome. All awesome, all the time:

{
    "uuids": [
        "5fcbbf2cb171b1d5c3bc6df3d4affb32",
        "9115e0942372a87a977f1caf30b2ac29",
        "3840b51b0b81b46cab99384d5cd106e3",
        "b848dbdeb422164babf2705ac18173e1",
        "b7a8566af7e0fc02404bb676b47c3bf7",
        "a006879afdcae324d70e925c420c860d",
        "5f7716ee487cc4083545d4ca02cd45d4",
        "35fdd1c8346c22ccc43cc45cd632e6d6",
        "97bbdb4a1c7166682dc026e1ac97a64c",
        "eb242b506a6ae330bda6969bb2677079"
    ]
}

sequential: Monotonically increasing ids with random increments. The first 26 hex characters are random, the last 6 increment in random amounts until an overflow occurs. On overflow, the random prefix is regenerated and the process starts over.

{
    "uuids": [
        "4e17c12963f4bee0e6ec90da54804894",
        "4e17c12963f4bee0e6ec90da5480512f",
        "4e17c12963f4bee0e6ec90da54805c25",
        "4e17c12963f4bee0e6ec90da54806ba1",
        "4e17c12963f4bee0e6ec90da548072b3",
        "4e17c12963f4bee0e6ec90da54807609",
        "4e17c12963f4bee0e6ec90da54807718",
        "4e17c12963f4bee0e6ec90da54807754",
        "4e17c12963f4bee0e6ec90da54807e5d",
        "4e17c12963f4bee0e6ec90da54808d28"
    ]
}

utc_random: The time since Jan 1, 1970 UTC, in microseconds. The first 14 characters are the time in hex. The last 18 are random.

{
    "uuids": [
        "04dd32b3af699659b6db9486a9c58c62",
        "04dd32b3af69bb1c2ac7ebfee0a50d88",
        "04dd32b3af69d8591b99a8e86a76e0fb",
        "04dd32b3af69f4a18a76efd89867f4f4",
        "04dd32b3af6a1f7925001274bbfde952",
        "04dd32b3af6a3fe8ea9b120ed906a57f",
        "04dd32b3af6a5b5c518809d3d4b76654",
        "04dd32b3af6a78f6ab32f1e928593c73",
        "04dd32b3af6a99916c665d6bbf857475",
        "04dd32b3af6ab558dd3f2c0afacb7d66"
    ]
}

utc_id: The time since Jan 1, 1970 UTC, in microseconds, plus the utc_id_suffix string. The first 14 characters are the time in hex. The uuids/utc_id_suffix string value is appended to these.

{
    "uuids": [
        "04dd32bd5eabcc@mycouch",
        "04dd32bd5eabee@mycouch",
        "04dd32bd5eac05@mycouch",
        "04dd32bd5eac28@mycouch",
        "04dd32bd5eac43@mycouch",
        "04dd32bd5eac58@mycouch",
        "04dd32bd5eac6e@mycouch",
        "04dd32bd5eac84@mycouch",
        "04dd32bd5eac98@mycouch",
        "04dd32bd5eacad@mycouch"
    ]
}

uuid_v7: UUID v7. The option uuids/format control the encoding format. The default is base_16.

{
    "uuids": [
       "0199df3833cc79c89bdde9530efc4f0c",
       "0199df3833cc7694af52300fce26dc2f",
       "0199df3833cc78bf93c0a7b7f1c00d5c",
       "0199df3833cc740d84ee0932e8ff1df3",
       "0199df3833cc751bb45b27cfbcc3c753",
       "0199df3833cc7a7cbce5469d3f52ba83",
       "0199df3833cc7b3f8c3f517a3a84b649",
       "0199df3833cc74b9b3cacaa0ebfbc842",
       "0199df3833cc7f49ae722b96ba1dbb3a",
       "0199df3833cc7db39f01868033e1dbec"
    ]
}

uuid_v4: UUID v4. The option uuids/format control the encoding format. The default is base_16.

{
    "uuids": [
        "e7981ba78fb844b4a87d18c54f4caef4",
        "f21cd92e8a4749f390cbd77f693514db",
        "4f469b5e6a374da3aa51271754ad027d",
        "0ae8035fe7fd42118ef693b996c2516d",
        "96250347ba69460197235d3809d74985",
        "2b3693f4503b47618df70c6bbe068af5",
        "cbec8e3375054a83b5f73fd115bb1500",
        "71589f1d9a9748beae8dc09bbe904d04",
        "59b581909b1d4f67a00aea5f29cfcb39",
        "4f33c962a3e64a5f89b05a05e680f3ee"
    ]
}

Note

Impact of UUID choices: the choice of UUID has a significant impact on the layout of the B-tree, prior to compaction.

For example, using the UUID v7 or sequential algorithms while uploading a large batch of documents will avoid the need to rewrite many intermediate B-tree nodes. A random UUID algorithm may require rewriting intermediate nodes on a regular basis, resulting in significantly decreased throughput and wasted disk space space due to the append-only B-tree design.

It is generally recommended to set your own UUIDs, or use the UUID v7 or sequential algorithms unless you have a specific need and take into account the likely need for compaction to re-balance the B-tree and reclaim wasted space.

format

Added in version 3.6.

Configure encoding format of UUID v4 and v7:

[uuids]
format = base_16

Available formats:

base_16: 32 byte long, hex-encoded value. For example: "0199df3759297032b402c3e61fbbf88f"
base_36: 25 byte long, base-36 encoded value using 0-9 and a-z characters. For example: "03eudcyamunnfraqdgmopx09b"
rfc9562: 36 byte long standard formatting for UUIDs (see https://www.rfc-editor.org/rfc/rfc9562) For example: "0199df37-5929-7032-b402-c3e61fbbf88f"

utc_id_suffix

Added in version 1.3.

The utc_id_suffix value will be appended to UUIDs generated by the utc_id algorithm. Replicating instances should have unique utc_id_suffix values to ensure uniqueness of utc_id ids.

[uuid]
utc_id_suffix = my-awesome-suffix

max_count

Added in version 1.5.1.

No more than this number of UUIDs will be sent in a single request. If more UUIDs are requested, an HTTP error response will be thrown.

[uuid]
max_count = 1000

3.16.4. Vendor information

[vendor]

Added in version 1.3.

CouchDB distributors have the option of customizing CouchDB’s welcome message. This is returned when requesting GET /.

[vendor]
name = The Apache Software Foundation
version = 1.5.0

3.16.5. Content-Security-Policy

[csp]

You can configure Content-Security-Policy header for Fauxton, attachments and show/list functions separately. See MDN Content-Security-Policy for more details on CSP.

utils_enable

Enable the sending of the header Content-Security-Policy for /_utils. Defaults to true:

[csp]
utils_enable = true

utils_header_value

Specifies the exact header value to send. Defaults to:

[csp]
utils_header_value = default-src 'self'; img-src 'self'; font-src *; script-src 'self' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; frame-src https://blog.couchdb.org;

blog.couchdb.org exists to cover the optional Fauxton News page.

attachments_enable

Enable sending the Content-Security-Policy header for attachments:

[csp]
attachments_enable = true

attachments_header_value

Specifies the exact header value to send. Defaults to:

[csp]
attachments_header_value = sandbox

showlist_enable

Enable sending the Content-Security-Policy header for show and list functions:

[csp]
showlist_enable = true

showlist_header_value

Specifies the exact header value to send. Defaults to:

[csp]
showlist_header_value = sandbox

The pre 3.2.0 behaviour is still honoured, but we recommend updating to the new format.

Experimental support of CSP headers for /_utils (Fauxton).

enable

Enable the sending of the Header Content-Security-Policy:

[csp]
enable = true

header_value

You can change the default value for the Header which is sent:

[csp]
header_value = default-src 'self'; img-src *; font-src *;

3.16.6. Configuration of Database Purge

[purge]

max_revisions_number

Added in version 3.0.

Changed in version 3.5.1.

Sets the maximum number of accumulated revisions allowed in a single purge request:

[purge]
max_revisions_number = infinity

index_lag_warn_seconds

Added in version 3.0.

Sets the allowed duration when index is not updated for local purge checkpoint document. Default is 24 hours:

[purge]
index_lag_warn_seconds = 86400

3.16.7. Configuration of Prometheus Endpoint

[prometheus]

additional_port

Added in version 3.2.

Sets whether or not to create a separate, non-authenticated port (default is false):

[prometheus]
additional_port = true

bind_address

Added in version 3.2.

The IP address to bind:

[prometheus]
bind_address = 127.0.0.1

port

Added in version 3.2.

The port on which clients can query prometheus endpoint data without authentication:

[prometheus]
port = 17986