PostgresLeaseStore

The LeaseStore on PostgreSQL: one row per (group, partition) in wow_lease and one per (service, node), with the node's internal address and the lease groups it serves (groups), in wow_lease_member, whose key column subscription_group holds the service.

Every operation is one autocommitted statement, on a connection the store borrows once and keeps: the store's operations run one at a time on it, so a renewal never waits behind the commands for a connection of the pool they share. A connection that fails as a connection (PostgresFailures.isTransient) is given back and the failure thrown; the next operation borrows another. The pool lends the commands one connection less, and a pool that detects leaks reports this one once. An acquisition is an upsert whose update applies only when the stored lease has expired or belongs to the acquiring node; PostgreSQL re-checks that condition against the latest row after waiting for a concurrent writer, so concurrent acquisitions have exactly one winner. A release keeps the row with expiry 0, so the next acquisition continues its epoch.

Times come from clock, so they are the calling node's: keep the TTL well above the nodes' clock skew. JDBC calls run on dispatcher, virtual threads by default.

Closing it gives the connection back to the pool, once the operation that holds it, if any, is done, waiting for it at most closeTimeout; an operation after that fails. Its store closes it when it is closed (me.ahoo.wow.spi.store.Store.close).