[MongoDB] Fix initial snapshot / Better error recovery

[rkistner]

Builds on #121.

1. Initial snapshot

Previously, we used {snapshot: true} to replicate an initial snapshot. That gives nice consistency guarantees, but cannot run longer than 5 minutes (configurable using minSnapshotHistoryWindowInSeconds). So this caused replication of larger amounts of data to fail.

This fixes it to not use the snapshot mode anymore, but rather just make sure we replicate all incremental changes since the start of the snapshot. This means data modified during the snapshot may be replicated twice, but that should not cause any consistency issues.

2. Error recovery

Replication errors are only cleared once we successfully replicate some data (when .commit(lsn) is called). Development instances are often mostly idle, which meant that if some transient error ever occurred, it could take a long time before the error is cleared from the dashboard.

This fixes it to create an internal checkpoint whenever we start replication, which will trigger at least one commit() (as long as replication is working), clearing the error.

[changeset-bot]

⚠️ No Changeset found

Latest commit: 00af63e

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

The base branch was changed.