Structure of a Blobspace Blobpage

The storage strategy used to store simple large objects in a blobspace differs from the dbspace storage strategy. The database server does not combine whole simple large objects or portions of a simple large object on a single blobspace blobpage. For example, if blobspace blobpages are 24 kilobytes each, a simple large object that is 26 kilobytes is stored on two 24-kilobyte pages. The extra 22 kilobytes of space remains unused.

The structure of a blobpage includes a blobpage header, the TEXT or BYTE data, and a page-ending time stamp. The blobpage header includes, among other information, the page-header time stamp and the blob time stamp associated with the forward pointer in the data row. If a simple large object is stored on more than one blobpage, a forward pointer to the next blobpage and another blob time stamp are also included in the blobpage header.


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