Shared-Memory Connections (UNIX)

A shared-memory connection uses an area of shared-memory as the channel through which the client and database server communicate with each other. Figure 3 illustrates a shared-memory connection.

Figure 3. A Shared-Memory Connection

Shared memory provides fast access to a database server, but it poses some security risks. Errant or malicious applications could destroy or view message buffers of their own or of other local users. Shared-memory communication is also vulnerable to programming errors if the client application performs explicit memory addressing or overindexes data arrays. Such errors do not affect the database server if you use network communication or stream pipes. For an example of a shared-memory connection, see Using a Shared-Memory Connection (UNIX).

A client cannot have more than one shared-memory connection to a database server.

For information about the portion of shared memory that the database server uses for client/server communications, see Communications Portion of Shared Memory (UNIX). For additional information, you can also see How a Client Attaches to the Communications Portion (UNIX).