ORA-12545: Connect failed because target host or object does not exist

[Oracle @ ybdbtest oradata] $ sqlplus/nolog


SQL * Plus: Release 9.2.0.4.0-Production on Thu Jun 26 10:16:29 2014


Copyright (c) 1982,200 2, Oracle Corporation. All rights reserved.

SQL> conn/as sysdba

ERROR:
ORA-12545: Connect failed because target host or object does not exist

I remember what happened when I got connected yesterday. Check whether the oracle process exists and the process is running.

[Oracle @ ybdbtest ~] $ Ps-ef | grep ora _
Oracle 5013 4499 0 00:00:00 pts/1 grep ora _
Oracle 11806 1 0 2013? 00:00:00 ora_q0020.szyb
Oracle 12212 1 0 2013? 00:08:51 ora_pmon_szyb
Oracle 12214 1 0 2013? 00:00:02 ora_psp0_szyb
Oracle 12216 1 0 2013? 00:00:00 ora_mman_szyb
Oracle 12218 1 0 2013? 00:03:25 ora_dbw0_szyb
Oracle 12220 1 0 2013? 00:03:35 ora_dbw1_szyb
Oracle 12222 1 0 2013? 00:03:36 ora_dbw2_szyb
Oracle 12224 1 0 2013? 00:05:56 ora_lgwr_szyb
Oracle 12226 1 0 2013? 02:13:23 ora_ckpt_szyb
Oracle 12228 1 0 2013? 00:19:35 ora_smon_szyb
Oracle 12230 1 0 2013? 00:00:00 ora_reco_szyb
Oracle 12232 1 0 2013? 00:06:43 ora_cjq0_szyb
Oracle 12234 1 0 2013? 00:40:47 ora_mmon_szyb
Oracle 12236 1 0 2013? 01:23:21 ora_mmnl_szyb
Oracle 12238 1 0 2013? 00:00:00 ora_d000_szyb
Oracle 12240 1 0 2013? 00:00:00 ora_s000_szyb
Oracle 12280 1 0 2013? 00:00:00 ora_qmnc_szyb
Oracle 12300 1 0 2013? 00:00:00 ora_q000_szyb

SQL * Plus: Release 9.2.0.4.0-Production on Thu Jun 26 10:16:29 2014 shows that the database version is 9i, and the version of yesterday is 10 Gb,

Check that both 9i and 10g versions are installed. Check the. bash_profile file and find that $ ORACLE_HOME points to 9i. Modify $ ORACLE_HOME to point

10g (mainly executable programs under the bin directory), connect again, successful:

[Oracle @ ybdbtest ~] $ Sqlplus/as sysdba


SQL * Plus: Release 10.2.0.5.0-Production on Thu Jun 26 11:01:17 2014


Copyright (c) 1982,201 0, Oracle. All Rights Reserved.




Connected:
Oracle Database 10g Enterprise Edition Release 10.2.0.5.0-64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

When multiple oracle versions are installed, pay attention to them.