commit
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Description
Finalizes the sync between the source cluster and the destination cluster and stops continuous sync between clusters.
For more information, see Finalize Cutover Process.
Requirements
Before using the commit
endpoint:
Stop your application to prevent any further writes to the source cluster. During commit, you may still read from the source cluster.
Warning
If you write to the source cluster during commit, you might experience data loss.
Use the progress endpoint to confirm the following values:
lagTimeSeconds
is near0
(Recommended, but not required)Note
lagTimeSeconds
lagTimeSeconds
indicates the time between the last applied event and time of the current latest event. When you send acommit
request,mongosync
enters theCOMMITTING
state for the amount of seconds reported bylagTimeSeconds
, and then transitions to theCOMMITTED
state.When
lagTimeSeconds
is0
, the source and destination clusters are in a consistent state.state: "RUNNING"
canCommit: true
Note
When you configure multiple mongosync
instances to sync between
sharded clusters, you must send identical API endpoint commands to each
mongosync
instance.
For more information, see Commit Synchronization From Multiple mongosync
Instances.
Request
POST /api/v1/commit
Request Body Parameters
This endpoint does not use HTTP request body parameters. However, you
must specify the --data
option with an empty object { }
.
Response
Field | Type | Description |
---|---|---|
success | boolean | When the request is successful, this value is true . |
error | string | If an error occurred, indicates the name of the error. This field
is omitted from the response when success is true . |
errorDescription | string | Detailed description of the error that occurred. This field is
omitted from the response when success is true . |
Example
The following example commits the synchronization operation to the destination cluster.
Confirm that the Synchronization is Ready
Before sending a request to the commit
endpoint, use the
progress endpoint to confirm that the
synchronization is ready to be committed.
Request
curl localhost:27182/api/v1/progress -XGET
Response
{ "progress": { "state":"RUNNING", "canCommit":true, "canWrite":false, "info":"change event application", "lagTimeSeconds":0, "collectionCopy": { "estimatedTotalBytes":694, "estimatedCopiedBytes":694 }, "directionMapping": { "Source":"cluster0: localhost:27017", "Destination":"cluster1: localhost:27018" }, "verification": { "source": { "estimatedDocumentCount": 42, "hashedDocumentCount": 42, "lagTimeSeconds": 2, "totalCollectionCount": 42, "scannedCollectionCount": 10, "phase": "stream hashing" }, "destination": { "estimatedDocumentCount": 42, "hashedDocumentCount": 42, "lagTimeSeconds": 2, "totalCollectionCount": 42, "scannedCollectionCount": 10, "phase": "stream hashing" } } }, "success": true }
The progress
endpoint returned "canCommit":true
, which means
that the commit
request can run successfully.
Send the Commit Request
The following command sends a request to the commit
endpoint:
Request
curl localhost:27182/api/v1/commit -XPOST --data '{ }'
Response
{"success":true}
Behavior
State
If the commit
request is successful, mongosync
enters the
COMMITTED
state. Once mongosync
enters the COMMITTED
state,
continuous sync between the clusters stops.
Data Verification
Before transferring your application load from the source cluster to the destination, check your data to ensure that the sync was successful.
For more information, see Verify Data Transfer.
Collection Characteristic Changes
commit
restores collection characteristics that mongosync
temporarily
alters during synchronization.
The following table illustrates the impact of commit
on collection
characteristics that mongosync
alters during the synchronization process.
Collection Characteristic | Impact of commit |
---|---|
Unique Indexes | commit resets unique indexes that mongosync replicated as
non-unique on the destination cluster. |
TTL Indexes | commit resets expireAfterSeconds which mongosync set
to the value of MAX_INT on the destination cluster. |
Hidden Indexes | commit resets hidden indexes that mongosync
replicated as non-hidden on the destination cluster. |
Write Blocking | If you enable write-blocking,
See also: Write Blocking |
Capped Collections | commit resets the required maximum size of capped collections
which mongosync set to the maximum allowable size on the
destination cluster. |
Endpoint Protection
mongosync
does not protect the commit
endpoint. However, by default
the API binds to localhost only and does not accept calls from other sources.
Additionally, the commit
call does not expose connection credentials
or user data.