Update the schema and implementation of the Postgres event indexer to improve
certain types of queries against the index. These changes address the use cases
raised by #6843, and are partly inspired by the prototype schema in that issue.
In the old schema, events were flattened, making it difficult to find all the events
associated with a particular block or transaction. In addition, events with no key/value
attributes were entirely lost, since entries were generated only for attributes.
To address these issues, this new schema records blocks, transactions, events,
and attributes in separate tables, and provides views that join these tables to
give a more convenient query surface for block and transaction events.
- All events for a given block can be queried from the `block_events` view.
- All events for a given transaction can be queried from the `tx_events` view.
- Multiple events for the same key can be indexed for both blocks and transactions.
The tests have been reworked, but all of the existing test cases for the old schema
still pass with the new implementation. Various other minor cleanups are included,
ADR-065 is also updated to reflect the updated schema.
M. J. Fromberger
7fe3e78a38