Consider droping off throttling in Ingestion Server filtered index creation

[krysal]

Problem

Due to previous performance problems with Elasticsearch (ES), a requests_per_second limit was settled to prevent index creation from affecting the search performance (#2975). Since indexes are created before promoting them to live usage, this feature should no longer be necessary.

openverse/ingestion_server/ingestion_server/indexer.py

Lines 495 to 500 in a675f46

	slices="auto",
	wait_for_completion=True,
	requests_per_second=ES_FILTERED_INDEX_THROTTLING_RATE,
	# Temporary workaround to allow the action to complete.
	request_timeout=48 * 3600,
	)

The ES CPU usage has been consistently below 50% for several weeks. Looking at the graph below, you can notice the highest peaks correspond to the creation of the image index and the following one to the capped filtered index. Letting ES autoregulate the number of items to ingest should optimize resource use and speed up the process.

Description

Remove the requests_per_second setting from the reindex call in the previously shown code block.

Alternatives

The other option is to keep trying to reach a number for ES_FILTERED_INDEX_THROTTLING_RATE that allows more ingestions per second without compromising the cluster stability.