Problem: Validator projection catching up speed is slow

[ysong42]

Solution: fixed #586

The main bottleneck is in handling BlockCreated event, we have some code that is updating all active validators' uptime. Previously, we are doing it in a loop manner, each validator will do one update SQL.

In my improved version, there are mainly two changes:

• update validators up time in batch mode, merge many update SQL into one
• Only updated uptime related columns, not updating all columns of validator

Update multiple rows reference: https://stackoverflow.com/a/26715934

Benchmark

the improvement is at BlockCreated-updateValidator column

Table columns:

Before optimization:

After optimization:

Benchmark data files (local indexer running against Crypto.org mainnet):
before-optimize-validator.csv
after-optimize-validator.csv

[ysong42]

I am not using squirrel library to generate the SQL. As update with from statement is not supported by the library yet...

Masterminds/squirrel#82
Masterminds/squirrel#291

[davcrypto]

LGTM