Overview

This project is about streaming Solana account updates into other databases or event queues.

Supported Solana sources:

• AccountsDB plugin (preferred) plus JSONRPC HTTP API (for initial snapshots)
• JSONRPC websocket subscriptions plus JSONRPC HTTP API (for initial snapshots)

Supported targets:

• PostgreSQL

Components

• accountsdb-plugin-grpc/

  The Solana AccountsDB plugin. It opens a gRPC server (see proto/) and broadcasts account and slot updates to all clients that connect.

• connector-lib/

  The connector abstractions that the connector service is built from.

  Projects may want to build their own connector service to decode account data before sending it into target systems.

Design and Reliability

Solana    --------------->   Connector   ----------->   PostgreSQL
 node       jsonrpc/gRPC      service

For reliability it is recommended to feed data from multiple Solana nodes into the Connector service. (That's not yet fully supported)

It is also allowed to run multiple Connector services that target the same PostgeSQL target database. (That's not yet fully supported)

The Connector service is stateless (except for some caches). Restarting it is always safe.

If the Solana node is down, the Connector service attempts to reconnect and then requests a new data snapshot if necessary.

If PostgeSQL is down temporarily, the Connector service caches updates and applies them when the database is back up.

If PostgreSQL is down for a longer time, the Connector service exits with an error. On restart, it pauses until PostgreSQL is back up, and then starts pulling data from the Solana nodes again.

PostgreSQL data layout

See scripts/ for SQL that creates the target schema.

The Connector streams data into the account_write and slot tables. When slots become "rooted", older account_write data rooted slots is deleted. That way the current account data for the latest rooted, committed or processed slot can be queried, but older data is forgotten.

When new slots arrive, the uncle column is updated for "processed" and "committed" slots to allow easy filtering of slots that are no longer part of the chain.

Example for querying committed data:

SELECT DISTINCT ON(pubkey) *
FROM account_write
INNER JOIN slot USING(slot)
WHERE status = "rooted" OR (uncle = FALSE AND status = "committed")
ORDER BY pubkey, slot DESC, write_version DESC;

For each pubkey, this gets the latest (most recent slot, most recent write_version) account data; limited to slots that are either rooted or (committed and not an uncle).