database-transaction-isolation-and-concu-module

atomicityThe all-or-nothing property: a transaction's effects are either fully applied or fully absent; implemented via

c009commit completion: the terminal state transition from active to committed; releases all locks held exclusively

isolation levelA configurable parameter defining the degree to which concurrent transactions are isolated from each other's u

aborted stateThe terminal transaction_state after rollback completes; all acquired locks are released and the transaction c

committed datadatabase state resulting from successfully completed transactions; constitutes the visible universe for read_c

rollbackThe act of undoing a transaction's effects using undo_log entries, returning the database to its pre-transacti

tl log recordThe fundamental unit of a transaction_log: a single append-only entry recording one atomic change or lifecycle

transaction stateThe current phase of a transaction lifecycle: active, partially_committed, committed, aborted; drives lock rel

read committedAn isolation_level where each statement sees only data committed before that statement begins; prevents dirty_

rr definitionAn isolation_level ensuring that all reads within a transaction see a consistent snapshot of the database as o

commitThe act of making a transaction's effects permanent: flush log records to durable storage, release locks, tran

row level lockingLock management at the individual row granularity via row_lock entries in lock_manager's lock table; enables h

acid propertiesThe four guarantees of database transactions: atomicity, consistency, isolation, durability — the foundational

concurrency controlThe set of mechanisms a DBMS uses to manage simultaneous access to shared data while preserving correctness an

database transactionA logical unit of work executed against a database, bounded by BEGIN and COMMIT/ROLLBACK, guaranteeing ACID pr

dirty readAn anomaly where a transaction reads data written by another transaction that has not yet committed; only poss

dur recovery managerThe subsystem that enforces durability by reconstructing the committed database state from transaction_log aft

dur write ahead loggingA protocol mandating that log records describing modifications be flushed to durable_storage before the corres

rr read lockA shared_lock acquired when a row is read under repeatable_read; held until transaction commits or rolls back,

tl recovery managerThe subsystem that, on system restart, reads the transaction_log from the last tl_checkpoint_record forward; r