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Introduction

The indexer is an Open, Flexible, Fast tool based on the SubQuery Framework. It is used to transform blockchain data into a graphql queryable database.

How it works:​

The indexer scans through each block and their events to see what happened on the Ternoa Blockchain. It then parses all that data into entities and inserts it in a postgres DB. Ternoa deploys its own indexer, and anybody can run his own.

You can get more information on the SubQuery official documentation

You can also check out our repository to see how we set up the subquery project to connect to the ternoa blockchain.

The most important files are:​

  • Project.yaml: set up the endpoint, the genesis hash, the types file, and the different filters to get only the specific events / extrinsics needed. We can also filter on the success status of the event / extrinsic. (More details on the docs)
  • Schema.graphql: specifies the custom data we need to record in our postgres db.
  • The Mappings folder: Your mappingHandlers will handle the functions to transform the blockchain data into the needed GraphQL entities contained in the Schema.graphql. More info here