Inheritance diagram for DatabaseHeader:
|Data segment version number at last checkpoint. |
|Memento for state of txn log at last checkpoint. |
|PageId of the oldest page in the shadow log needed for recovery. |
|Whenever a database is opened, except during recovery, a new UUID is generated to represent the online lifetime of the database. |
|Magic number identifying the derived StoredNode class. |
Static Public Attributes
|static const MagicNumber||MAGIC_NUMBER = 0xa513a9e27bc336acLL|
(Two pages because an identical copy is stored as part of a careful-write protocol when checkpointing.)
Definition at line 41 of file DatabaseHeader.h.
Data segment version number at last checkpoint.
Referenced by Database::checkpointImpl(), Database::closeImpl(), Database::createDataSegment(), Database::init(), Database::loadHeader(), Database::openSegments(), Database::recoverPhysical(), and Database::restoreFromBackup().
Whenever a database is opened, except during recovery, a new UUID is generated to represent the online lifetime of the database.
The primary use is for marking log pages so that disk blocks written by previous instances can't masquerade as usable log pages during recovery.