Listener on rinkeby issues a large number of eth_getLogs requests

[franckc]

I think due to the fact that we haven't had traffic on the rinkeby dapp for a while, the listener event-cache ends up querying very large ranges of block (100 of thousands of blocks) for logs. See the listener logs:

[DEBUG] event-listener: Processing from 6205480 for ProxyFactory
[INFO]  event-listener: Querying events within interval (6205480, 6591767)
2020-06-01T17:19:35.936Z event-cache Skipped loading event from IPFS cache.
2020-06-01T17:19:35.940Z event-cache Get 386286 blocks in 155 requests
2020-06-01T17:19:39.263Z event-cache setLatestBlock to 6591767
2020-06-01T17:19:39.263Z event-cache setLatestBlock to 6591767
2020-06-01T17:19:39.263Z event-cache setLatestBlock to 6591767
2020-06-01T17:19:39.263Z event-cache setLatestBlock to 6591767
2020-06-01T17:19:41.594Z event-cache Got 0 new events
[DEBUG] event-listener: Got 200 unfiltered events within interval for ProxyFactory
[INFO]  event-listener: Got 0 new events for ProxyFactory

[DEBUG] event-listener: Processing from 6041255 for V000_Marketplace
[INFO]  event-listener: Querying events within interval (6041255, 6591767)
2020-06-01T17:19:41.601Z event-cache Skipped loading event from IPFS cache.
2020-06-01T17:19:41.603Z event-cache Get 550512 blocks in 56 requests
2020-06-01T17:19:45.425Z event-cache Got 0 new events
[DEBUG] event-listener: Got 2673 unfiltered events within interval for V000_Marketplace
[INFO]  event-listener: Got 0 new events for V000_Marketplace

[DEBUG] event-listener: Processing from 6568018 for V001_Marketplace
[INFO]  event-listener: Querying events within interval (6568018, 6591767)
2020-06-01T17:19:45.440Z event-cache Skipped loading event from IPFS cache.
2020-06-01T17:19:45.441Z event-cache Get 23749 blocks in 3 requests
2020-06-01T17:19:46.353Z event-cache Got 0 new events
[DEBUG] event-listener: Got 340 unfiltered events within interval for V001_Marketplace
[INFO]  event-listener: Got 0 new events for V001_Marketplace

This causes a fairly large volume of requests to Alchemy (~6qps). Unfortunately those requests are fairly expensive and they are chewing our quota quite quickly.

As a stopgap, I have disabled the listener on Rinkeby since anyway the traffic shows nobody is using it.