Some transaction failed during massive test

[kukugi]

Summary

Some transaction failed with error message when send transaction continuously

Test environment

test-net have 100 instances
os: cent-os 7.7
cpu: 2vCPU_4GB
storage: 50GB_SSD
abci: persistent_kvstore

Problem Definition

It sends transactions every 5m.
message below is a error response from node when send a transaction continuously.

{ 
  code: -32603,
  message: 'Internal error',
  data: 'tx already exists in cache'
}

I have tested that in two situation

1. Send all of transactions to a one node
2. Send transactions to each nodes

but, both get same error response

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[egonspace]

I think it's possible the same tx may be made as following the form val:{keyType}!{pubKey}!{amount}, isn't it?

[kukugi]

issue raise tendermint/tendermint#6027