Quiescing and Suspending the Database
You can temporarily quiesce or suspend the database during your maintenance operations. Using
these options allows you to keep the database open during application maintenance, avoiding the
time or availability impact associated with database shutdowns.
While the database is quiesced, no new transactions will be permitted by any accounts other
than SYS and SYSTEM. New queries or attempted logins will appear to hang until you unquiesce
the database. The quiesce feature is useful when performing table maintenance or complicated
data maintenance. To use the quiesce feature, you must first enable the Database Resource
Manager, as described earlier in this chapter. In addition, the RESOURCE_MANAGER_PLAN
initialization parameter must have been set to a valid plan when the database was started, and
it must not have been disabled following database startup.
While logged in as SYS or SYSTEM (other SYSDBA privileged accounts cannot execute these
commands), quiesce the database as follows:
alter system quiesce restricted;
Any non-DBA sessions logged into the database will continue until their current command
completes, at which point they will become inactive. In Real Application Clusters configurations,
all instances will be quiesced.
To see if the database is in quiesced state, log in as SYS or SYSTEM and execute the following
query:
select Active_State from V$INSTANCE;
The Active_State column value will be either NORMAL (unquiesced), QUIESCING (active non-
DBA sessions are still running), or QUIESCED.
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