design_memo.txt

Additional GUC

Worker process local socket
Worker process port (for the comunication to other worker)
max_nodes
max_g_trans

Worker process to Worker process

1. Update node latest valid clock.
2. Request upadte node latest valid clock.
3. Update node earliest reference clock.
4. Request node earliest reference clock.
5. Register node
6. Unregistger nocde

Shared memory among worker process and backends

1. Node info
2. Global transaction info

Backend to local worker process

1. Request update external node latest valid clock
2. Request shm handle
3. Update root transaction completion clock
4. Upadte root transaction reference clock -> Initiate earliest reference clock update broadcast.

Parent backend to child backend

1. XID notification
2. node notification
3. transaction reference clock notification

Worker process specific:

1. Cleanup global transaction info (based upon earliest reference clock update)
2. Expand node information from the schema.

pgxl.pgxl_nodes(
		uint32	nodeid;
		struct timeval latest_valid_clock;
		struct timeval earliest_ref_clock;
		int	   sender_sock;
		int	   receiver_sock;
		uint32 sender_port;
		char   addr[ADDR_MAX+1];
		);

Backend process specific:

1. Create child global transaction info entry.
2. Update transaction completion clock.
3. Create root (parent) global transaction info entry.
4. Setup transaction reference clock.
5. Setup transaction completion clock. (parent/child)

* Sequence: define sequence host and visit the host for sequence.