Tuesday, 13 March 2012

Buffer management

SQL Server buffers pages in RAM to abbreviate disc I/O. Any 8 KB folio can be buffered in-memory, and the set of all pages currently buffered is alleged the absorber cache. The bulk of anamnesis accessible to SQL Server decides how abounding pages will be buried in memory. The absorber accumulation is managed by the Absorber Manager. Either account from or autograph to any folio copies it to the absorber cache. Subsequent reads or writes are redirected to the in-memory copy, rather than the on-disc version. The folio is adapted on the disc by the Absorber Manager alone if the in-memory accumulation has not been referenced for some time. While autograph pages aback to disc, asynchronous I/O is acclimated whereby the I/O operation is done in a accomplishments cilia so that added operations do not accept to delay for the I/O operation to complete. Each folio is accounting forth with its checksum aback it is written. Aback account the folio back, its checksum is computed afresh and akin with the stored adaptation to ensure the folio has not been damaged or tampered with in the meantime.42

No comments:

Post a Comment