Struct ClientSession 

pub struct ClientSession {

    pub id: Uuid,
    pub client_addr: SocketAddr,
    pub current_node: RwLock<Option<String>>,
    pub in_transaction: AtomicBool,
    pub copy_in_progress: AtomicBool,
    pub tx_state: RwLock<TransactionState>,
    pub variables: RwLock<HashMap<String, String>>,
    pub created_at: DateTime<Utc>,
    pub tr_mode: TrMode,
    pub last_write_at: RwLock<Option<Instant>>,
    pub pool_client_id: ClientId,
    pub plugin_identity: RwLock<Option<Identity>>,
    pub edge_ineligible: AtomicBool,
    pub pending_edge_copy_tables: Mutex<Option<Vec<String>>>,
}

Client session

Fields

id: Uuid

Session ID

client_addr: SocketAddr

Client address

current_node: RwLock<Option<String>>

Current backend node

in_transaction: AtomicBool

Fast, lock-free “in a transaction” flag — the single per-query hot-path read/write of transaction state. Written from the ReadyForQuery status byte at each response boundary; read by pool-release, read-node selection, and cache-eligibility checks. This is authoritative on the data path; tx_state (below) retains the richer structure for TR/replay consumers but is no longer touched per query, so the relay pays no RwLock acquisition just to test in-transaction.

copy_in_progress: AtomicBool

Set while the session is mid-COPY (the backend sent CopyInResponse / CopyBothResponse and is awaiting CopyData from the client). A COPY is NOT a clean transaction boundary even though no ReadyForQuery has been seen yet, so Transaction/Statement pool release must be suppressed while it is set — otherwise the connection would be reset (DISCARD ALL) and parked in the middle of a copy, aborting it and hanging the client. Cleared once the COPY drains to ReadyForQuery.

tx_state: RwLock<TransactionState>

Rich transaction state (tx id, statement log, savepoints) for Transaction-Replay/library consumers. Not read or written on the per-query forward path — see in_transaction above.

variables: RwLock<HashMap<String, String>>

Session variables

created_at: DateTime<Utc>

Created at

tr_mode: TrMode

TR mode for this session

last_write_at: RwLock<Option<Instant>>

Wall-clock instant of this session’s most recent write, for read-your-writes routing: reads within the configured window after a write are pinned to the primary so the client observes its own writes despite replica lag.

pool_client_id: ClientId

Client ID for pool-modes lease tracking

plugin_identity: RwLock<Option<Identity>>

Identity returned by an Authenticate plugin, if any. Downstream plugins (masking, residency routing, cost governor) read this to gate per-user policy. None when no plugin ran or every plugin deferred to the default auth flow.

edge_ineligible: AtomicBool

Sticky edge-cache ineligibility: set once the session executes any statement that alters execution context (SET/SET ROLE/search_path, temp tables, …). The shared edge cache keys on (fingerprint, params, db/user, startup vars) — it cannot see session-local GUC state, so a session that mutates it must never read from or store into the shared cache again (cross-session wrong-rows otherwise).

pending_edge_copy_tables: Mutex<Option<Vec<String>>>

Tables of an in-flight COPY ... FROM awaiting its CopyDone drain. COPY rows become visible at drain time, so the edge invalidation is deferred until then (never held across an await).