lec03.468

lec03.468 - . . Spring 2008 . CSC 468: DBMS Implementation...

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. Spring 2008 CSC 468: DBMS Implementation Alexander Dekhtyar . . Buffer Manager and Buffer Management Buffer Manager Overview Buffer Manager is a component of a DBMS responsible for the following opera- tions and services: Management and maintenance of buffer space : the main memory space des- ignated to store data read from disk; Reading data from disk into buffer space; Flushing data from buffer space onto disk; Providing access to the relational data to the query execution layer of the DBMS; Buffer space consists of M chunks of memory. The size of each chunk is equal to the size of a disk block. Each chunk (buffer) stores data from a single disk block. The Buffer Manager has one key property: The Buffer Manager operates asynchronously w.r.t. other compo- nents of the DBMS 1 . When a Read() request is processed, the Buffer Manager ensures that by the end of the request the necessary data re- sides in the buffer. However, when a Write() request is processed by the Buffer Manager , the updated page does not immediately get writ- ten back to disk. Rather, it stays in the buffer space until a later time, when the Buffer Manager chooses to flush the page back to disk. 1 The components include query execution layer, transaction scheduler and crash recovery mod- ule. 1
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This note was uploaded on 05/19/2008 for the course CSC 468 taught by Professor Dehktyar during the Spring '08 term at Cal Poly.

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lec03.468 - . . Spring 2008 . CSC 468: DBMS Implementation...

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