Transactions

Transactions

Generated from MemCP commit c42e19eba on 27 August 2026. See Full SCM API documentation.

The Transactions module manages transaction contexts stored in a session. It provides cursor-stability transactions, ACID snapshot/OCC transactions, commit, rollback, and implicit autocommit wrapping.

These functions are runtime primitives used by the SQL frontend. Applications normally use BEGIN, COMMIT, and ROLLBACK; see Transactions and Isolation for visibility, conflict, and durability semantics.

tx_begin

Begins a new cursor-stability transaction. Takes the session function as argument. Stores the transaction context in the session.

Allowed number of parameters: 1–1

Parameters

• session (func): the session function to store tx state in
  • Parameters
    • key (string) (optional)
    • value (any) (optional)
  • Returns
    • value (any)

Returns

• value (bool)

tx_begin_acid

Begins a new ACID transaction with snapshot isolation and OCC commit. Takes the session function as argument.

Allowed number of parameters: 1–1

Parameters

• session (func): the session function to store tx state in
  • Parameters
    • key (string) (optional)
    • value (any) (optional)
  • Returns
    • value (any)

Returns

• value (bool)

tx_commit

Commits the current transaction.

Allowed number of parameters: 1–1

Parameters

• session (func): the session function that holds tx state
  • Parameters
    • key (string) (optional)
    • value (any) (optional)
  • Returns
    • value (any)

Returns

• value (bool)

tx_rollback

Rolls back the current transaction.

Allowed number of parameters: 1–1

Parameters

• session (func): the session function that holds tx state
  • Parameters
    • key (string) (optional)
    • value (any) (optional)
  • Returns
    • value (any)

Returns

• value (bool)

with_autocommit

Executes fn inside an implicit TxCursorStability transaction if no explicit transaction is active in session. Commits on success, rolls back on error, and re-raises any panic so the caller's error handler still fires. If an explicit transaction is active (session["transaction"] != nil), fn is executed without any wrapping.

Allowed number of parameters: 2–2

Parameters

• session (func): the session function holding tx state
  • Parameters
    • key (string) (optional)
    • value (any) (optional)
  • Returns
    • value (any)
• fn (func): zero-argument function to execute
  • Returns
    • value (any)

Returns

• value (any)