TNS-12535: TNS:operation timed out — Oracle DB

Another way is to use this command in the batch file:

echo exit | sqlplus user/pass@connect @scriptname

Via OEM 10g,

1. Connect to the database as usual
2. Click on the Schema tab
3. On the Tables link within Database Objects
4. Enter the schema name and object name (optional) and click Go
5. Use the radio button to select the table you want to look at and click on Edit (Don't click on the table name link)
6. Click on the Segments tab (and wait...)
7. You will see the size of the table data and the indexes used.

OK, that technically answered your question. But a better way is:

1. Logon using SQLPLUS
2. Run the script from Vincent.

I like to save the script as t.sql as a quick reference

COLUMN size_mb      FORMAT '999,999,990.0'
COLUMN num_rows     FORMAT '999,999,990'
COLUMN fmt_short    FORMAT A24


COLUMN owner        FORMAT A16
COLUMN table_name   LIKE fmt_short
COLUMN tablespace_name  LIKE fmt_short

SET LINESIZE 200
SET AUTOTRACE OFF

COMPUTE SUM OF size_mb ON REPORT
BREAK ON REPORT

SELECT 
    lower( owner )      AS owner
    ,lower(table_name)  AS table_name
    ,tablespace_name
    ,num_rows
    ,blocks*8/1024      AS size_mb
    ,pct_free
    ,compression 
    ,logging
FROM    all_tables 
WHERE   owner           LIKE UPPER('&1')
OR  owner           = USER
ORDER BY 1,2;

CLEAR COMPUTES
CLEAR BREAKS