The BTree page dialog interprets a BTree page and it's various fields.

btreepage.png

At the top of this dialog is the "File Range Control". The file range control gives you a quick graphical view of where in the file this page is located.

Next comes the BTPage Trailer. This is located at the end of the page, right before the page trailer. It includes basic information about how to interpret this page, such as:
  • cEnt The number of entries on this page
  • cEntMax The maximum number of entries allowed on this page
  • cbEnt The size of each entry
  • cLevel The level of this page (zero for a leaf page, or distance from a leaf page)

The page trailer area includes an interpretation of the fields of the page trailer structure. They include:
  • ptype The type of this page
  • ptypeRepeat The type of this page. Should match ptype.
  • wSig The page signature. This is based on the id and location of the page on disk
  • dwCRC The CRC of the page. This is validated everytime the page is read from disk.
  • bid The id of the page.

Below the page trailer is the contents of the page. This is a tree control, graphically displaying the various entries on this BTree page. Note that for non-leaf pages only the immediate children of the displayed root node actually represent data on this page. this tree control will dynamically load other BTree pages from the file in order to fill out the tree control as you expand further nodes.

Last edited Apr 5, 2010 at 5:34 PM by terrymah, version 4

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