VersionedPageFooter Struct Reference

Information stored in the footer of each page of a VersionedSegment. More...

List of all members.

Public Attributes
PageId	dataPageId
	For an old version stored in the log, this is the PageId of the latest version in the data segment.
SegVersionNum	versionNumber
	The version number of this page.
PseudoUuid	onlineUuid
	The UUID of the online instance that logged this version.
uint64_t	checksum
	For an old version stored in the log, this is a checksum of the logged contents, used to find the last good page during recovery.

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Detailed Description

Information stored in the footer of each page of a VersionedSegment.

Note that some of this information is only relevant in old page versions stored in the log segment, but the footer size has to be reserved for logging.

Definition at line 41 of file VersionedSegment.cpp.

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Member Data Documentation

PageId VersionedPageFooter::dataPageId

For an old version stored in the log, this is the PageId of the latest version in the data segment.

For the latest version in the data segment, this is NULL_PAGE_ID.

Definition at line 48 of file VersionedSegment.cpp.

Referenced by VersionedSegment::notifyPageDirty(), and VersionedSegment::recover().

SegVersionNum VersionedPageFooter::versionNumber

The version number of this page.

Definition at line 53 of file VersionedSegment.cpp.

Referenced by VersionedSegment::getPageVersion(), VersionedSegment::notifyPageDirty(), and VersionedSegment::recover().

PseudoUuid VersionedPageFooter::onlineUuid

The UUID of the online instance that logged this version.

Definition at line 58 of file VersionedSegment.cpp.

Referenced by VersionedSegment::notifyPageDirty(), and VersionedSegment::recover().

uint64_t VersionedPageFooter::checksum

For an old version stored in the log, this is a checksum of the logged contents, used to find the last good page during recovery.

For the latest version in the data segment, this is 0.

Definition at line 65 of file VersionedSegment.cpp.

Referenced by VersionedSegment::notifyPageDirty(), and VersionedSegment::recover().

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The documentation for this struct was generated from the following file:

• /home/pub/open/dev/fennel/segment/VersionedSegment.cpp

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