Package com.sleepycat.db

Class LockMode

java.lang.Object
com.sleepycat.db.LockMode
public final class LockMode extends Object
Locking modes for database operations. Locking modes are required parameters for operations that retrieve data or modify the database.

  • Field Details

    • DEFAULT

      public static final LockMode DEFAULT
      Acquire read locks for read operations and write locks for write operations.

    • READ_UNCOMMITTED

      public static final LockMode READ_UNCOMMITTED
      Read modified but not yet committed data.

    • READ_COMMITTED

      public static final LockMode READ_COMMITTED
      Read committed isolation provides for cursor stability but not repeatable reads. Data items which have been previously read by this transaction may be deleted or modified by other transactions before the cursor is closed or the transaction completes.

      Note that this LockMode may only be passed to Database get methods, not to Cursor methods. To configure a cursor for Read committed isolation, use CursorConfig.setReadCommitted(boolean).

    • RMW

      public static final LockMode RMW
      Acquire write locks instead of read locks when doing the retrieval. Setting this flag can eliminate deadlock during a read-modify-write cycle by acquiring the write lock during the read part of the cycle so that another thread of control acquiring a read lock for the same item, in its own read-modify-write cycle, will not result in deadlock.

    • DIRTY_READ

      public static final LockMode DIRTY_READ
      Deprecated.
      This has been replaced by READ_UNCOMMITTED to conform to ANSI database isolation terminology.
      Read modified but not yet committed data.

    • DEGREE_2

      public static final LockMode DEGREE_2
      Deprecated.
      This has been replaced by READ_COMMITTED to conform to ANSI database isolation terminology.
      Read committed isolation provides for cursor stability but not repeatable reads. Data items which have been previously read by this transaction may be deleted or modified by other transactions before the cursor is closed or the transaction completes.

      Note that this LockMode may only be passed to Database get methods, not to Cursor methods. To configure a cursor for Read committed isolation, use CursorConfig.setReadCommitted(boolean).

    • IGNORE_LEASES

      public static final LockMode IGNORE_LEASES
      Return the data item irrespective of the state of master leases. The item will be returned under all conditions: if master leases are not configured, if the request is made to a client, if the request is made to a master with a valid lease, or if the request is made to a master without a valid lease.

  • Method Details