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FAQ
Common gotchas and how-tos

I try to run Hydra Indexer for my node but see Registry: ERROR: createType errors

This error indicates that the indexer type definitions are not properly set. Hydra Indexer v3 takes the default types from @polkadot/[email protected] which is compatible with runtimes built on Substrate 3.x but may cause errors when run against older versions of Substrate
Make sure that
    All the custom types are properly defined in the type definition json and the indexer has picked them up
    Adress and Signature are decoded properly. This page may be helpful for troubleshooting

How do I access extrinsic data in an event handler?

EventContext has an extrinsic field containing all the relevant extrinsic data if the event was emitted by an extrinsic. Further, one can create a type-safe extrinsic class using the constructor method generated by typegen.

I want to bootstrap some external data not available via events or extrinsics

Export the data into a json file and load into the database via a one-off preBlockHook at the desired height. See mapping filters for more details.

How do I deal with runtime upgrades?

To inject some new data, define a one-off block hook triggered at the block height with the upgrade. In order to have different versions of event/extrinsic handlers for pre- and post- upgrade, use specVersion filter.
Last modified 4mo ago