Objective: Solution for ORA-27102 : out of memroy error & TNS Protocol adapter error ORA12505 in Oracle Dtaabase 11g r2 on Windows
ORA-2702:
Sometimes there is the possiblity that your database will be shutsown by some process and then you will be unable to connect to the database either because of not enough shared memery
available or TNS protocol adapter . If you get ORA-27102 : out of memory error as shown in below screen shot.
Move to the folder containing init.ora . Open this init.ora file and update the memory_target variable to 2.5G , so that out of memory problem is solved . You will find the init.ora file in
app/oracle/product/11.2.0/dbhome_1/dbs.
And then try to startup the database after restarting the machine you should be able to connect
SQL> startup force;
ORACLE instance started.
Total System Global Area 2622255104 bytes
Fixed Size 2216224 bytes
Variable Size 1627393760 bytes
Database Buffers 973078528 bytes
Redo Buffers 19566592 bytes
Database mounted.
Database opened.
Cause of ORA-12505:
The listener received a request to establish a connection to a database or other service. The connect descriptor received by the listener specified a SID for an instance (usually a database
instance) that either has not yet dynamically registered with the listener or has not been statically configured for the listener. This may be a temporary condition such as after the listener has started,
but before the database instance has registered with the listener.
To solve the protocol adapter error ORA-12505 open the tnsnames.ora file available in dbhome_1/network/admin and update the correcr SERVICE_NAME which was given while installation of
11gR2.