Issue Summary

The pre-flight check for BCMA experiences significant slowness when handling a large user base, impacting migration efficiency and user experience.

This is reproducible on Data Center: Yes

Steps to Reproduce

1. Initiate a pre-flight check with a large dataset or user base.
2. Observe the time taken for the pre-flight check to complete.

Expected Results

The pre-flight check should complete within a reasonable timeframe, allowing for efficient migration processes.

Actual Results

The pre-flight check takes an extended period to complete, causing delays in the migration process. The log entries related to the "c.a.b.p.b.p.AsyncCheckExecutor Pre-flight check" indicate that the pre-flight check takes long amount of time to complete.

Example:

2024-10-07 09:01:25,200 INFO  [bcma-1] C_AMI @XXX XXX 10.30.0.60,172.19.0.3 "POST /rest/migration/latest/check/XXX HTTP/1.1" c.a.b.p.b.p.AsyncCheckExecutor Pre-flight check started [None::bb419b106ba08bc4af41cf85833bb828439ee8e9::UserMaxNumber]

2024-10-07 10:02:36,899 INFO  [bcma-0] C_AMI @XXX XXX 10.30.0.60,172.19.0.3 "POST /rest/migration/latest/check/XXX HTTP/1.1" c.a.b.p.b.p.AsyncCheckExecutor Pre-flight check finished successfully [None::bb419b106ba08bc4af41cf85833bb828439ee8e9::UserMaxNumber] 

Workaround

The only solution is to filter users entering Bitbucket, which will significantly reduce the number of users in the system and improve speed.

Refer: https://confluence.atlassian.com/bitbucketserver/connect-to-an-ldap-directory-776640403.html