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Pooled Postgres client built on psycopg_pool.AsyncConnectionPool.

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EXPLICIT_DSN_POOL_MAX_SIZE

tai42_kit.clients.impl.postgres.EXPLICIT_DSN_POOL_MAX_SIZE

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EXPLICIT_DSN_POOL_MIN_SIZE

tai42_kit.clients.impl.postgres.EXPLICIT_DSN_POOL_MIN_SIZE

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PostgresClient

tai42_kit.clients.impl.postgres.PostgresClient
Pooled psycopg_pool.AsyncConnectionPool, one pool per DSN per loop. The pool is named <owner>@<host>/<db>; min_size/max_size are this database’s deployment settings read when the pool is built; a second settings prefix resolving to the same DSN with different sizes raises. Compose PostgresConnectionSettings for the connection kwargs.

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open_dedicated_pool

tai42_kit.clients.impl.postgres.open_dedicated_pool
Open a dedicated (not shared) named pool for role, its first connection proven and its fill awaited. A settings object supplies the DSN and the deployment’s pool sizes; a DSN string gets EXPLICIT_DSN_POOL_MIN_SIZE / EXPLICIT_DSN_POOL_MAX_SIZE. The pool is named postgres@<host>/<db>:<role>; connection_kwargs apply to every connection it opens. The caller owns the pool and closes it. Parameters

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pinned_connection

tai42_kit.clients.impl.postgres.pinned_connection
Yield one dedicated connection held for the whole context. A one-connection pool (min_size == max_size == 1) built outside the shared cache, named <owner>@<host>/<db>:pinned, opened through the same probe and bounded fill as the pooled path. The caller holds exactly one connection, so a session-scoped advisory lock taken on it covers every statement in the body, and a driver error on it never touches the shared pool. The pool and its connection close on any exit — normal return, exception, or cancellation. Parameters

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postgres_pool_name

tai42_kit.clients.impl.postgres.postgres_pool_name
The psycopg_pool name for a database pool: <owner>@<host>/<db>. Host and database come from the DSN via conninfo_to_dict — never the user or password, which must not reach a pool name that surfaces in log lines. A non-empty role appends a :<role> suffix so a dedicated pool (a pinned connection, a langgraph store/checkpoint pool) is distinguishable in the logs. Parameters

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read_connection

tai42_kit.clients.impl.postgres.read_connection
A pooled connection in autocommit mode for stand-alone reads: each statement runs on its own, no BEGIN/COMMIT. Plain SELECTs only. A locking read (FOR UPDATE / FOR SHARE), a write, or statements that must be atomic together run on pool.connection() inside conn.transaction(). The pool must be a PostgresClient pool, whose reset callback returns the connection to transactional mode when it comes back. Parameters