Speedup address to logs query

[vbaranov]

Motivation

Logs tab on address page:

For almost all addresses if there are tons of transactions in the chain like in ETH Mainnet.

Changelog

1. Replace index on logs table on block_number field with a multicolumn index block_number DESC, index DESC to be able to sort in logs table

2. Change the query to use this index.

The query is transformed from

SELECT l0.* FROM logs AS l0
INNER JOIN transactions AS t1
ON ((t1.block_hash = l0.block_hash)
AND (t1.block_number = l0.block_number))
AND (t1.hash = l0.transaction_hash)
WHERE (((t1.block_number < 9125388))
OR ((t1.block_number = 9125388)
AND (t1.index > 0))
OR (((t1.block_number = 9125388) AND (t1.index = 0))
AND (l0.index > 0)))
AND ((l0.address_hash = '\xdac17f958d2ee523a2206206994597c13d831ec7')
AND (l0.block_hash = t1.block_hash))
ORDER BY t1.block_number DESC, t1.index DESC LIMIT 51;

to

SELECT COUNT(a.*) FROM (
  SELECT l0.*
  FROM logs AS l0
  INNER JOIN transactions AS t1
  ON t1.hash = l0.transaction_hash
  WHERE (l0.address_hash = '\xdac17f958d2ee523a2206206994597c13d831ec7')
  AND (((t1.block_number < 9125388))
  OR ((t1.block_number = 9125388)
  AND (t1.index > 0))
  OR (((t1.block_number = 9125388) AND (t1.index = 0))
  AND (l0.index > 0)))
  ORDER BY l0.block_number DESC, l0.index DESC LIMIT 51
) a
INNER JOIN transactions AS t1 ON a.block_hash = t1.block_hash
AND a.block_number = t1.block_number
AND a.transaction_hash = t1.hash

Checklist for your Pull Request (PR)

• I added an entry to CHANGELOG.md with this PR
• If I added new functionality, I added tests covering it.
• If I fixed a bug, I added a regression test to prevent the bug from silently reappearing again.
• I checked whether I should update the docs and did so by submitting a PR to https://github.com/blockscout/docs
• If I added/changed/removed ENV var, I submitted a PR to https://github.com/blockscout/docs to update the list of env vars at https://github.com/blockscout/docs/blob/master/for-developers/information-and-settings/env-variables.md and I updated the version to master in the Version column. Changes will be reflected in this table: https://docs.blockscout.com/for-developers/information-and-settings/env-variables.
• If I add new indices into DB, I checked, that they are not redundant with PGHero or other tools

[coveralls]

Pull Request Test Coverage Report for Build 37d89e4a-0835-4cd7-9a8b-34fa3fd93339

• 2 of 2 (100.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.007%) to 75.447%

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Totals
Change from base Build 40db3a00-b82e-4dfe-90f8-b3b8b7d7679a:	0.007%
Covered Lines:	5313
Relevant Lines:	7042

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💛 - Coveralls