Daily Archives: 07.09.2023

Get history of Switchover and Failover of an Oracle database

This entry was posted in Audit Oracle on by

For physical standbys, there is no DBA_* view that I know which tracks the history of switchover and failover. For Logical standby there is DBA_LOGSTDBY_HISTORY.

Ways to find the information are the Dataguard Broker log – when Broker is in use -, or using the database alert log and the following grep command:

$ grep -EB1 '^ALTER DATABASE (SWITCHOVER|FAILOVER) TO' alert_*.log

2023-03-06T14:12:38.905705+01:00
ALTER DATABASE SWITCHOVER TO 'mydb2'
--
2023-03-06T14:37:43.209653+01:00
ALTER DATABASE FAILOVER TO MYDB1
--
2023-03-06T14:38:03.352141+01:00
ALTER DATABASE SWITCHOVER TO PRIMARY (MYDB1)
--
2023-03-11T16:00:22.224218+01:00
ALTER DATABASE SWITCHOVER TO 'mydb2'

Goldengate 21 for DB2 on z/OS and segmentation fault

This entry was posted in DB2 zOS GoldenGate on by

These days I’ve been trying Goldengate 21 for DB2 on z/OS (Extract). And still surprises!

Last year, with Goldengate 21.6, it would simply corrupt trailfiles if the extract abended.

This year, with Goldengate 21.10, After adding a new extract,the extract abends without any error or explanation. The report file would remain with this:

2023-06-21 15:11:31 INFO OGG-25184

Using DB2 subsystem DBZOS.

Only in the /var/log/messages one could see:

Jun 21 15:11:31 oraclevm1 kernel: extract[281329]: segfault at 0 ip 00007f1c5cca609f sp 00007ffcabd65c28 error 4 in libc-2.17.so[7f1c5cc0b000+1c4000]

SR open and Oracle says, it is fixed with Goldengate 21.11, which is released in two weeks. Well… almost. With Goldengate 21.11 the extract still crashes but only about five minutes after the start command. And the error on /var/log/messages is little different:

Aug 28 13:29:50 oraclevm1 kernel: extract[154775]: segfault at 170 ip 00005569d4916a82 sp 00007ffe69d1e600 error 4 in extract[5569d4415000+aaa000]

Oracle says – yes, sorry. Please try the workaround to create the extract with:

ADD EXTRACT e_ab, TRANLOG, EOF

When I check the Goldengate 21 documentation for “ADD EXTRACT” , this option is not valid for DB2 for z/OS, but ok. I try and it works.

Checking with Oracle, the information is that when doing:

ADD EXTRACT e_ab, TRANLOG, BEGIN NOW

It stores the time we run the command and, when we start the extract, it will scan the DB2 log to find the LSN (Log Sequence Number or the CSN from DB2) corresponding to that time. In this scan operation is the bug that makes the segmentation fault. Using EOF, it will always use the end of the Transaction Log at the time we start the Extract.

The Goldengate documentation will be updated soon to add that EOF is also valid for DB2 for z/OS.

My ADRCI cheatsheet

This entry was posted in Oracle on by

Check last problems

adrci> show problem -last 10
adrci> show incident -last 10

adrci> show incident -p "incident_id=180781" -mode detail

Create Package

adrci> ips create package problem 5
adrci> ips generate package 1 in "/tmp"

Purge

Value for control is hours

adrci> show control
adrci> set control (SHORTP_POLICY = 720)   /* 30 days */
adrci> set control (LONGP_POLICY= 8760)   /* 1 year */

Value for purge is minutes

adrci> purge -age 1440  /* 1 day */

Fix “No ADR base is set”

Sometimes also “DIA-48494: ADR home is not set”

SQL> select value from v$diag_info where name='ADR Base';
VALUE
------------------
/u01/app/oracle

Create a ${ORACLE_HOME}/log/diag/adrci_dir.mif file with:

$ mkdir -p ${ORACLE_HOME}/log/diag/
$ printf "%s\0" "/u01/app/oracle" > ${ORACLE_HOME}/log/diag/adrci_dir.mif

DIA-48448: This command does not support multiple ADR homes

Use set home diag/xxxxx (remove the ORACLE_BASE path)

adrci> show problems -last 10

ADR Home = /u01/app/oracle/diag/rdbms/mydb1/MYDB1:
...

adrci>  set home diag/rdbms/mydb1/MYDB1