There are good resources within the PostgreSQL documentation and Wiki regarding streaming replication. For more information, please visit these URLs:
- Log-shipping standby servers: https://www.postgresql.org/docs/current/static/warm-standby.html
- Streaming replication: https://wiki.postgresql.org/wiki/Streaming_Replication
- Synchronous replication: https://wiki.postgresql.org/wiki/Synchronous_replication
- Write Ahead Log: https://www.postgresql.org/docs/current/static/runtime-config-wal.html