How to fix ORA-12547 TNS lost contact when try to connect to Oracle

Issue / Oracle error

sqlplus scott/tiger
SQL*Plus: Release 10.2.0.5.0 - Production on Wed May 18 09:32:35 2011
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ERROR:
ORA-12547: TNS :lost contact when try to connect to Oracle.

Issue description

I saw that TNS connection issue along with ORA-12547 Oracle error several times, usually when trying to connect to Oracle database server on Unix / Linux host with an OS user that does not belong to oinstall group (Oracle binaries owner group).  In this case, interesting enough that local TNS connection to database (when using tnsnames alias) works fine: Read more »

Oracle Data Pump (expdp) schema export fails with ORA-01801

Platform

Oracle Database Server 10gR2 (10.2.0.5)

Problem

Data Pump (expdp) schema export fails on Oracle 10gR2 with following Oracle error:

ORA-39125: Worker unexpected fatal error in KUPW$WORKER.UNLOAD_METADATA while calling DBMS_METADATA.FETCH_XML_CLOB [TABLE_STATISTICS]
ORA-01801: date format is too long for internal buffer
ORA-06512: at "SYS.DBMS_SYS_ERROR", line 105
ORA-06512: at "SYS.KUPW$WORKER", line 6313
Read more »

Oracle Listener refused connection ORA-12519 troubleshooting

Platform

Oracle database 11gR2 (11.2.0.2.2)

Problem

New database connection attempts to Oracle database 11gR2 fail with following Oracle error:

Listener refused the connection with the following error: ORA-12519, TNS:no appropriate service handler found   [SQLCode: 12519], [SQLState: 66000] None None

Read more »

Unable to DDL due to Oracle Spatial and XDB

I’ve just encountered an interesting Oracle database issue that was not described properly on the Internet. So, I’ve decided to give a solution in this post.

The issue is that you simply can not execute certain DDL (Data Definition Language) SQL statements due to the strange behavior of Oracle triggers and Oracle error ORA-00604 and ORA-04098. Read more »

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