oracle 也推出来了数据库的top命令，叫做oratap,是使用c语言写的，目前只支持linux x86与x64的11gR2与12cR1
使用说明

[oracle@xifenfei tmp]$ ./oratap  -h
oratop: Release 13.2.4
Usage:
         oratop [ [Options] [Logon] ]
         Logon:
                {username[/password][@connect_identifier] | / }
                [AS {SYSDBA|SYSOPER}]
         Options:
             -i : Interval Delay (requires value in seconds, default: 3s)
             -f : Long format for header & section 4 (default: 80 column)
             -r : IORL mode for Section 2 (default is IOPS)
             -d : Real-Time Top 5 Wait Events (default: Cumulative)
             -m : MODULE/ACTION mode for Section 4 (default: USER/PROGRAM_NAME)
             -b : Batch mode
             -n : maximum number of iterations (requires number)
             -h : Help

使用说明
1. Log in to the system as the Oracle RDBMS software installation owner
2. Stage the oratop executable on the server on which the tool will be executed. On a RAC system it is only necessary to stage the executable on one node as it is RAC aware.
3. Change the name of the executable, eg.

$ mv oratop* oratop

4. Validate the permissions for oratop are 755 (-rwxr-xr-x). If the permissions are not currently set to 755, set the permissions on oratop as follows:

$ chmod 755 oratop

5. Configure the execution environment as follows (if not already set accordingly)

$ export TERM=xterm #or vt100
$ export ORACLE_HOME=<11.2 database home>
$ export LD_LIBRARY_PATH=$ORACLE_HOME/lib
$ export PATH=$ORACLE_HOME/bin:$PATH
$ export ORACLE_SID=<local 11.2 database SID to be monitored> #only needed if connecting to a local database

6. Invoke the tool to monitor a local database as follows (interval can be any interval in seconds):

$ ./oratop -i 10 / as sysdba

7. Non-dba privileged user requires specific grants to use the tool. See User Guide for grants required.
8. Databases can be monitored remotely using a tns alias as described in the oratop Users Guide .

$ ./oratop -i 10 username/password@tns_alias
$ ./oratop -i 10 system/manager@tns_alias

9. To exit the program simply press the keyboard key “q”. To abort, CTRL-C.
Troubleshooting:
If you receive an error similar to
./oratop: error while loading shared libraries: libclntsh.so.11.1: cannot open shared object file: No such file or directory that is an indication that libclntsh.so.11.1 was not found in the path defined in LD_LIBRARY_PATH similar to

$ export LD_LIBRARY_PATH=$ORACLE_HOME/lib (ie., the location of libclntsh.so.11.1)

使用效果

[oracle@xifenfei tmp]$ ./oratap  -i 10 chf/xifenfei@ora11g_p
oratop: Release 13.2.4 Production on Mon Aug 26 03:10:17 2013
Copyright (c) 2011, Oracle.  All rights reserved.
Processing ...
oratop 1:  148 ora1 03:10:13 up  3.3m,  1 ins, 301M mt,   3 sn,  1 us,   6% db
ID %CU HLD MBPS IOPS %FR PGAU ASC ASI ASW ASP   AAS USN  TPS UCPS SSRT DBC DBW
 1   0   0    0    1   5 133M   1   0   0   0   0.1   3    0    2   0u   0   0
EVENT     (Cumulative)           TOT WAITS  TIME(s)  AVG_MS PCT  WAIT_CLASS
DB CPU                                          218          68
control file parallel write           5535       30     5.5   9  System I/O
db file sequential read              10080       27     2.7   8  User I/O
os thread startup                      198       25   124.9   8  Concurrency
db file async I/O submit              2575       21     8.0   7  System I/O
ID   SID  SPID USR PROG  PGA OPN SQLID/BLOCKER  E/T STATUS STE WAIT_EVENT  W/T
 1   148  8254 CHF DEDI   2M SEL 4agz3g5aajkdc    0 ACTIVE CPU wa for cpu   0u

参考文档:
oratop – utility for near real-time monitoring of databases, RAC and Single Instance (Doc ID 1500864.1)