Tokens service: GraphQL - Combined userCredits and userDebits queries

[brandonfancher]

This is a nice to have; we're not planning immediate pagination support for Pending Transactions in the UI at the moment. But if/when we do want to paginate, we won't be able to do so with the current UI, which combines the userCredits and userDebits queries into one table.

[James-Mart]

Proposal

Table 1: Shared Balance Table

Almost identical to today's shared-balance table

Column	Type	Description
shared_bal_id	u64	<-- NEW!
creditor	accountnumber
debitor	accountnumber
token_id	TID (u32)
balance	quantity

Indexes:

• Primary key = shared_bal_id

Table 2: User Pending Summary

Add two records for every shared balance record

1. One for the creditor
2. One for the debitor

Column	Type
user	string
token_id	TID (u32)
shared_bal_id	u64

Indexes:

• Primary key = { User, token_id, shared_bal_id }

Notes:

• I think that other indexes for Shared Balance Table can be removed

• Enables efficient searches on:
  • All pending transactions that involve a user (across all tokens, either creditor or debitor)
  • All pending transactions that involve a user for a particular token (either creditor or debitor)