Package org.h2.mvstore.tx

Class Transaction

java.lang.Object
org.h2.mvstore.tx.Transaction
public final class Transaction extends Object
A transaction.

  • Field Details

    • STATUS_CLOSED

      public static final int STATUS_CLOSED
      The status of a closed transaction (committed or rolled back).
      See Also:

    • STATUS_OPEN

      public static final int STATUS_OPEN
      The status of an open transaction.
      See Also:

    • STATUS_PREPARED

      public static final int STATUS_PREPARED
      The status of a prepared transaction.
      See Also:

    • STATUS_COMMITTED

      public static final int STATUS_COMMITTED
      The status of a transaction that has been logically committed or rather marked as committed, because it might be still listed among prepared, if it was prepared for commit. Undo log entries might still exists for it and not all of it's changes within map's are re-written as committed yet. Nevertheless, those changes should be already viewed by other transactions as committed. This transaction's id can not be re-used until all of the above is completed and transaction is closed. A transactions can be observed in this state when the store was closed while the transaction was not closed yet. When opening a store, such transactions will automatically be processed and closed as committed.
      See Also:

  • Method Details

    • getId

      public int getId()

    • getSequenceNum

      public long getSequenceNum()

    • getStatus

      public int getStatus()

    • hasChanges

      public boolean hasChanges()
      Determine if any database changes were made as part of this transaction.
      Returns:
      true if there are changes to commit, false otherwise

    • setName

      public void setName(String name)

    • getName

      public String getName()

    • getBlockerId

      public int getBlockerId()

    • setSavepoint

      public long setSavepoint()
      Create a new savepoint.
      Returns:
      the savepoint id

    • hasStatementDependencies

      public boolean hasStatementDependencies()
      Returns whether statement dependencies are currently set.
      Returns:
      whether statement dependencies are currently set

    • getIsolationLevel

      public IsolationLevel getIsolationLevel()
      Returns the isolation level of this transaction.
      Returns:
      the isolation level of this transaction

    • allowNonRepeatableRead

      public boolean allowNonRepeatableRead()
      Whether this transaction has isolation level READ_COMMITTED or below.
      Returns:
      true if isolation level is READ_COMMITTED or READ_UNCOMMITTED

    • markStatementStart

      public void markStatementStart(HashSet<MVMap<Object,VersionedValue<Object>>> maps)
      Mark an entry into a new SQL statement execution within this transaction.
      Parameters:
      maps - set of maps used by transaction or statement is about to be executed

    • markStatementEnd

      public void markStatementEnd()
      Mark an exit from SQL statement execution within this transaction.

    • openMap

      public <K, V> TransactionMap<K,V> openMap(String name)
      Open a data map.
      Type Parameters:
      K - the key type
      V - the value type
      Parameters:
      name - the name of the map
      Returns:
      the transaction map

    • openMap

      public <K, V> TransactionMap<K,V> openMap(String name, DataType<K> keyType, DataType<V> valueType)
      Open the map to store the data.
      Type Parameters:
      K - the key type
      V - the value type
      Parameters:
      name - the name of the map
      keyType - the key data type
      valueType - the value data type
      Returns:
      the transaction map

    • openMapX

      public <K, V> TransactionMap<K,V> openMapX(MVMap<K,VersionedValue<V>> map)
      Open the transactional version of the given map.
      Type Parameters:
      K - the key type
      V - the value type
      Parameters:
      map - the base map
      Returns:
      the transactional map

    • prepare

      public void prepare()
      Prepare the transaction. Afterwards, the transaction can only be committed or completely rolled back.

    • commit

      public void commit()
      Commit the transaction. Afterwards, this transaction is closed.

    • rollbackToSavepoint

      public void rollbackToSavepoint(long savepointId)
      Roll back to the given savepoint. This is only allowed if the transaction is open.
      Parameters:
      savepointId - the savepoint id

    • rollback

      public void rollback()
      Roll the transaction back. Afterwards, this transaction is closed.

    • getChanges

      public Iterator<TransactionStore.Change> getChanges(long savepointId)
      Get the list of changes, starting with the latest change, up to the given savepoint (in reverse order than they occurred). The value of the change is the value before the change was applied.
      Parameters:
      savepointId - the savepoint id, 0 meaning the beginning of the transaction
      Returns:
      the changes

    • setTimeoutMillis

      public void setTimeoutMillis(int timeoutMillis)
      Sets the new lock timeout.
      Parameters:
      timeoutMillis - the new lock timeout in milliseconds

    • waitFor

      public boolean waitFor(Transaction toWaitFor, String mapName, Object key, int timeoutMillis)
      Make this transaction to wait for the specified transaction to be closed, because both of them try to modify the same map entry.
      Parameters:
      toWaitFor - transaction to wait for
      mapName - name of the map containing blocking entry
      key - of the blocking entry
      timeoutMillis - timeout in milliseconds, -1 for default
      Returns:
      true if other transaction was closed and this one can proceed, false if timed out

    • removeMap

      public <K, V> void removeMap(TransactionMap<K,V> map)
      Remove the map.
      Type Parameters:
      K - the key type
      V - the value type
      Parameters:
      map - the map

    • toString

      public String toString()
      Overrides:
      toString in class Object