in doubt transaction

Distributed transactions allows you to have multiple DML’s over multiple databases within a single transaction For instance, one local and one remote insert into t values(1); insert into t@db02 values(2); commit; If you lose connection to db02 and wants to commit, your database server may/does not know about the state of the remote transaction. The […]

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How to migrate non-cdb to pdb

In case you are desesperately looking for an upgrade from non-cdb to pdb with two clicks, here is the answer from Mike : you can’t Nope – not via "upgrade". You can use Data Pump, Transportable Tablespaces or Full Transportable Export/Import as a direct option but you can't upgrade and plugin in one pass unfortunately […]

FBI = function based index

Let me today tell you, I now hate FBI for real. Let’s start with an easy working example SQL> CREATE TABLE t(x NUMBER PRIMARY KEY) Table created. SQL> insert into t(x) values (1) 1 row created. SQL> insert into t(x) values (2) 1 row created. SQL> insert into t(x) values (3) 1 row created. SQL> […]

Administrative privileges like SYSDBA

The most well-known administrative privilege is sysdba. Back in Oracle 7.2, oracle recommended to no longer use the INTERNAL but to connect as sysdba. A second one, seldom used, is SYSOPER. When you use sqlplus / as sysdba, or connect / as sysdba in sqlplus / srvmgrl, the you log as SYS. That’s the most […]

check invalid directories


check invalid database link for the DBA

followup of check invalid database link If you need to check db link in another schema, you need to create code that run with that schema. base on the example from yesterday, here is an extended version for the dba CREATE FUNCTION dba_status (owner VARCHAR2, db_link VARCHAR2) RETURN VARCHAR2 IS PRAGMA AUTONOMOUS_TRANSACTION; status VARCHAR2 (4000); […]

check invalid database link

If one database link is invalid, you cannot select through it SQL> select * from dual@z; select * from dual@z * ERROR at line 1: ORA-02019: connection description for remote database not found However, there is no STATUS command in your user_db_links table that you could use. For this purpose, write a function. create function […]

execute sql script from pl/sql

When you want to run a SQL script, you rather use sqlplus. If you want to run it within a PL/SQL stored procedure, you are screwed. You could redo the logic of sqlplus, this is what any decent IDE and code runnner does, and it’s a pile of work and you will get lot’s of […]

What is the instance name?

If your Oracle SID doesn’t match your instance name in init.ora, this is quite confusing. Check my previous post, what is sid in oracle In the instance_name column of the view v$instance, as well as in USERENV context, it matches the ORACLE_SID of the underlying operating system. SQL> var ORACLE_SID varchar2(9) SQL> set autoprint on […]

Generate 11g password hash

An easy way to generate a value string from the ssl is to use openssl Let’s take a random salt of ABCDEFGHIJ. The length of 10 is important. The hexadecimal representation is -41-42-43-44-45-46-47-48-49-4A- $ echo “SafePassw0rDABCDEFGHIJ\c” | openssl dgst -sha1 (stdin)= 47cc4102144d6e479ef3d776ccd9e0d0158842bb With this hash, I can construct my value SQL> create user testuser identified […]

delete all data

How do you delete all data? The simplistic approach would be to truncate all tables SQL> select table_name from user_tables; TABLE_NAME ———- T1 SQL> truncate table t1; Table truncated. You cannot truncate if you have referential integrity constraints. SQL> truncate table t2; ORA-02266: unique/primary keys in table referenced by enabled foreign keys Ok, let’s disable […]

tracefile tim to readable date format

In trace file, the time is recorded, this could be used to measure time between two timestamps But how do you convert 31796862227375 to a human format? This is how I proceeded : SQL> oradebug SETMYPID Statement processed. SQL> oradebug tracefile_name /u01/log/oracle/diag/rdbms/db01/DB01/trace/DB01_ora_32440740.trc SQL> alter session set nls_date_format=’YYYY-MM-DD_HH24:MI:SS’ sql_trace=true; Session altered. SQL> select ‘&_DATE’,’Start’ from dual; […]

job_name cannot be null

exec dbms_scheduler.create_job(job_name=>null,job_type=>’PLSQL_BLOCK’,job_action=>’BEGIN NULL; END;’) ORA-27451: JOB_NAME cannot be NULL ORA-06512: at “SYS.DBMS_ISCHED”, line 146 ORA-06512: at “SYS.DBMS_SCHEDULER”, line 288 ORA-06512: at line 1 This sounds like a proper error message. A bit less obvious is the drop_job message SQL> exec dbms_scheduler.drop_job(job_name=>null) ORA-20001: comma-separated list invalid near ORA-06512: at “SYS.DBMS_UTILITY”, line 236 ORA-06512: at “SYS.DBMS_UTILITY”, line […]

DELETE is faster than TRUNCATE

Truncate is useful in some serial batch processing but it breaks the read-write consistency, generates stranges errors and results for running selects, and it needs DROP ANY TABLE when run over a table that you do not own. But also, DELETE is faster in the following test case. In 12c, you could have over one […]

Irrecoverable part III : a fix

After part I:the problem, Part II: two reports here is part III. We have backed up archivelog during a full and deleted them before the full completed. RMAN> list backup of archivelog all; List of Backup Sets =================== BS Size Type Elapsed Completion — —— —- ——– ———- 15 4.00K DISK 00:00:00 13:31:08 BP Key: […]

Irrecoverable full backup part II : reporting

After my post Can you restore from a full online backup ?, I needed to come up with a report. Assuming that each backup goes in a different directory, I just wrote two reports. Report gaps in v$backup_redolog (or rc_backup_redolog if you use the catalog) DIR FIRST_CHANGE# NEXT_CHANGE# ——- ————- ———— /bck01/ 284891 285140 /bck01/ […]

Can you restore from a full online backup ?

The question is not HOW TO DO IT but WHETHER YOU CAN DO IT ! A typical backup script would contains something like BACKUP DATABASE PLUS ARCHIVELOG: backup database format ‘/u99/backup/DB01/20150518/full_0_%d_s%s_p%p’ plus archivelog format ‘/u99/backup/DB01/20150518/arc_%d_s%s_p%p’; Starting backup at 2015-05-18_18:27:55 current log archived input archived log thread=1 sequence=469 … piece handle= /u99/backup/DB01/20150518/arc_DB01_s86_p1 Finished backup at 2015-05-18_18:27:58 […]

bypass ora-20

When you really need to run one script, at all cost, an annoying error is ORA-00020: maximum number of processes (40) exceeded, which can even occurs as sysdba. Test case (21 is a not something to do in real life): SQL> alter system set processes=21 scope=spfile; System altered. SQL> startup force quiet ORACLE instance started. […]

switch user in Oracle

Almost a decade ago I wrote about su in sqlplus. This 10gR2 “new” feature allows delegation à la sudo. By checking the DBA_USERS in 12c I found PROXY_ONLY_CONNECT. According to Miguel Anjo, there is a secret syntax for allowing only the proxy user. SQL> ALTER USER app_user PROXY ONLY CONNECT; SQL> CONNECT app_user/xyz ERROR:ORA-28058: login […]

Unusable index

After table maintenance, like move or split partition, underlying indexes are marked as unusable. This boils down to segment reorganisation, not dictionary change. For instance : CREATE TABLE t(x NUMBER) PARTITION BY RANGE(x) (PARTITION p1 VALUES LESS THAN (MAXVALUE)); CREATE INDEX i ON t (x); INSERT INTO t VALUES (1); ALTER TABLE T SPLIT PARTITION […]

Did you forget to run

Not easy to detect, and depending on the product (agent/database), it may have only limited side effects. Like external jobs not running, operating systems statistics not collected. But it is not always easy to diagnose. For instance if you patch from OMS 12cR2 to 12cR3, and you run the only in 12cR2, they are […]

last partition

if you really need to quickly find the latest partition per table, I have written this little gem WITH FUNCTION d (b BLOB, len number) RETURN DATE IS d DATE; BEGIN IF DBMS_LOB.SUBSTR (b, 1, 1) = hextoraw(’07’) and len=83 THEN DBMS_STATS.convert_raw_value (DBMS_LOB.SUBSTR (b, 12, 2), d); ELSE d := NULL; END IF; RETURN d; […]

Do you have a partition in 2015

You need to check the high_value from dba_tab_partitions. Or you you could metadata. With metadata, it is not a long, it either clob or clob-xml. SELECT t.table_name, MAX ( TO_DATE ( REGEXP_SUBSTR ( EXTRACT ( (VALUE (x)), ‘HIBOUNDVAL’).getStringVal (), ‘ \d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}’), ‘YYYY-MM-DD HH24:MI;:SS’)) high_value FROM user_tables t, TABLE ( XMLSEQUENCE ( EXTRACT ( xmltype […]

poor man ActiveDirectory password checker

To have the same users in multiple databases and no single sign on is quite a nightmare for password expiration, synchronisation and validation. You probably were discouraged by the long long route to kerberos, where the bugs are fixed in, the 12.1 bugs are fixed in 12.2. And lot’s of system changes that […]

import into UTF8 database

A common error when you import single-byte characters (e.g. iso8859p1 or mswin1252) into multi-bytes databases (e.g. utf8) is ORA-12899: value too large for column. The root cause is the default semantics in a database being BYTE SQL> select VALUE, ISDEFAULT from v$parameter where NAME=’nls_length_semantics’ VALUE ISDEFAULT ——- ——— BYTE TRUE It means, one char equals […]

ssl version

I wrote about ssl version in jdbc thin yesterday The default version also no longer works for the thick client with 12c client and 11g Server. With 11gR2 : C:> tnsping (DESCRIPTION=(ADDRESS=(PROTOCOL=TCPS)(HOST=SRV01)(PORT=1521))) TNS Ping Utility for 64-bit Windows: Version OK (100 msec) with 12cR1 : C:> tnsping (DESCRIPTION=(ADDRESS=(PROTOCOL=TCPS)(HOST=SRV01)(PORT=1521))) TNS Ping Utility for 64-bit Windows: […]

check if using tcps part II

in your current session, as written there, check sys_context(‘USERENV’, ‘NETWORK_PROTOCOL’) in another session, you could grab some hints out of the network service banner. Do the maths, when it is not-not using ssl, it probably is… select sid,program, case when program not like ‘ora___@% (P%)’ then (select max(case when NETWORK_SERVICE_BANNER like ‘%TCP/IP%’ then ‘TCP’ when […]