Sybase Adaptive Server IQ 12.4.2, Administration And Performance Manual

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Overview of transactions and versioning
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Figure 8-2: One writer, multiple readers
Multiple writers and readers in a database
Within an IQ database that is not multiplex, multiple read-only and read/write
users can operate concurrently, as long as the writers are inserting data into (or
deleting it from) different tables. So, for example, while User 1’s transaction is
inserting and deleting in the
customer
table, User 2 can begin a transaction that
loads data into the
employee
table, as shown in Figure 8-3. At the same time
other users can execute transactions that issue queries to both of these tables,
or to any other tables in the database.
In an IQ Multiplex database, read/write users must all connect to the write
server, whereas read-only users can connect to any query server or the write
server. For more information, see Adaptive Server IQ Multiplex User’s Guide.