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The server process attaches to the shared memory used for the SGA and can
read from it and write to it.
As the name implies, the server process works for the client process??”it reads and
passes back the requested data, accepts and makes changes on behalf of the client,
and so on. For example, when a client wants to read a row of data stored in a particular
database block, the server process identifies the desired block and either
retrieves it from the database buffer cache or reads it from the correct datafile and
loads it into the database buffer cache. Then, if the user requests changes, the server
process modifies the block in the cache and generates and stores the necessary redo
information in the redo log buffer in the SGA. The server process, however, does not
Accessing a Database | 71
write the redo information from the log buffer to the redo log files, and it does not
write the modified database block from the buffer cache to the datafile. These
actions are performed by the Log Writer (LGWR) and Database Writer (DBWR)
processes, respectively.


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