A look into Oracle redo, part 5: the log writer writing
This the the fifth blog in a series of blogposts about Oracle database redo. The previous blog looked into the ‘null write’ (kcrfw_do_null_write actually) function inside kcrfw_redo_write_driver, which...
View ArticleA look into Oracle redo, part 6: oracle post-wait commit and the on disk SCN
This is the sixth part in a blog series about Oracle database redo. The previous posts provided information about the log writer writing, this post is about the process that is waiting after issuing...
View ArticleA look into oracle redo, part 7: adaptive log file sync
This is the seventh part of a blog series about oracle redo.Adaptive log file sync is a feature that probably came with Oracle version 11.2. Probably means I looked at the undocumented parameters of...
View ArticleA look into oracle redo, part 8: generate redo
This blogpost looks at the very start of oracle redo: the generation of it. In order to do that, I start off with a very simple table, and look at the redo generation part. I guess the regular readers...
View ArticleA look into oracle redo, part 9: commit
The previous blogpost talked about a simple insert, this blogpost investigates what happens when the DML is committed. Of course this is done with regular commit settings, which means means they are...
View ArticleA look into oracle redo, part 9a: commit – concurrency considerations
During the investigations of my previous blogpost about what happens during a commit and when the data becomes available, I used breaks in gdb (GNU debugger) at various places of the execution of an...
View ArticleA look into oracle redo, part 10: commit_wait and commit_logging
The redo series would not be complete without writing about changing the behaviour of commit. There are two ways to change commit behaviour:1. Changing waiting for the logwriter to get notified that...
View ArticleA look into oracle redo: index and overview
I gotten some requests to provide an overview of the redo series of blogposts I am currently running. Here it is:read more
View ArticleA look into oracle redo, part 11: log writer worker processes
Starting from Oracle 12, in a default configured database, there are more log writer processes than the well known ‘LGWR’ process itself, which are the ‘LGnn’ processes: $ ps -ef | grep test | grep lg...
View ArticleFlamegraph with function annotation
Recently, Franck Pachot tweeted the following:read more
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