Segmentation Fault What are segmentation faults (segfaults), and how can I identify what’s causing them? Debugging Segmentation Faults and Pointer Problems Debugging with GDB GDB Command Reference (gdb) info frame Stack level 0, frame at 0xb75f7390: eip = 0x804877f in base::func() (testing.cpp:16); saved eip 0x804869a called by frame at 0xb75f73b0 source language c++.… Continue reading Segmentation Fault

Tcp Zero Window TCP Zero Windows – and Why They Can Be VERY Bad TCP zero windows FIN says “i finished talking to you, but i’ll still listen to everything you have to say until you’re done” RST says “there is no conversation. i won’t say anything and i won’t listen to anything you say” –… Continue reading Tcp Zero Window

Breaking yum infinite loop

When executing “yum update openssl*”, it seems yum runs into infinite loop: –> Running transaction check —> Package gmp.x86_64 0:4.3.1-7.el6_2.2 will be updated –> Processing Dependency: for package: cloog-ppl-0.15.7-1.2.el6.x86_64 –> Processing Dependency: for package: ppl-0.10.2-11.el6.x86_64 —> Package python.x86_64 0:2.6.6-29.el6_2.2 will be updated –> Processing Dependency: python(abi) = 2.6 for package: pygtksourceview-2.8.0-1.el6.x86_64 –> Processing… Continue reading Breaking yum infinite loop

Useful docs regarding Application Continuity

Graceful Application Switchover in RAC with No Application Interruption (Doc ID 1593712.1) Client and Application Failover Validation Matrix (Doc ID 1617163.1) PDB Failover in a Data Guard environment: Unplugging a Single Failed PDB from a Standby Database and Plugging into a New Container (Doc ID 2088201.1) Understanding Transparent Application Failover (TAF) and Fast Connection Failover… Continue reading Useful docs regarding Application Continuity

Why doesn’t SELECT release IS lock in DB2

I came across this question when analyzing the following application snapshot: Application Snapshot Application handle = 56710 Application status = UOW Waiting <<<<<<<<<<< UOW Waiting means DB2 server is waiting for application submit the next statement, does NOT indicate the current transaction has committed. Status change time = 02/26/2017 12:30:01.381390 Application code page = 1208… Continue reading Why doesn’t SELECT release IS lock in DB2

Step-by-step guide on installing Oracle RAC on RHEL7.3 (part VI)

9. Configure database 9.1 Configure redo log files By default, dbca will only create 2 redo log groups for each thread and the size of each redo log file is only 50M. We need to increase redo log file size to 1G and redo log group to 5 for each thread. — add 3 additional… Continue reading Step-by-step guide on installing Oracle RAC on RHEL7.3 (part VI)