Review Request - Impact on database load for enabling advanced global search

Scaling Request

The feature/improvement we'd like some assistance with is: Enabling Advanced Global Search for Paid Groups on GitLab.com gitlab-org&1736 (closed)

The epic and relevant issues are: gitlab-org/gitlab#214280 (comment 332665387)

The reason we're asking for a scaling review on this item is:

From: #365 (comment 342830038) We proposed to increase the number of sidekiq nodes handling initial indexing jobs, which are mostly read-only jobs, gitlab-org/gitlab#214280 (comment 332665387). However, we are not sure of the impact on database load.

In particular, we are concerned about:

• Memory
• Migrations
• N+1
• Queueing
• Design implementation
• Database load
• Other...

We're hoping to release this as part of milestone: not specified