The PostgreSQL Global Development Group has released an important update with fixes for multiple security issues to all supported versions of the PostgreSQL database system, which includes minor versions 9.4.1, 9.3.6, 9.2.10, 9.1.15, and 9.0.19. This update includes both security fixes and fixes for issues discovered since the last release. In particular for the 9.4 update, there is a change to the way unicode strings are escaped for the JSON and JSONB data types.
The PostgreSQL memory at first sight looks simple. If compared with the complex structures implemented in the other DBMS to a careless reader could seem rudimentary. However, the memory and in particular the shared buffers implementation is complex and sophisticated. This chapter will dig down deep into the PostgreSQL’s memory.
3.1 The shared buffer The shared buffer is a segment allocated at cluster’s startup. Its size is determined by the GUC parameter shared_buffers and the size can be changed only restarting the cluster.
2.4 The background writer Before the spread checkpoints the only solution to ease down the IO spike caused by the checkpoint was to tweak the background writer. This process were introduced with the revolutionary PostgreSQL 8.0. The writer, as the name suggests, works in the background searching for dirty buffers to write on the data files. The writer works in rounds. When the process awakes scans the shared buffer for dirty buffers.
The cluster in action PostgreSQL delivers his services ensuring the ACID rules are enforced at any time. This chapter will give an outlook of a ``day in the life’' of a PostgreSQL’s cluster. The chapter approach is purposely generic. At this stage is very important to understand the global picture rather the technical details.
After the startup When the cluster completes the startup procedure it starts accepting the connections. When a connection is successful then the postgres main process forks into a new backend process which is assigned to the connection for the connection’s lifetime.
The acronym RTFM stands for Read The Fucking Manual. It’s quite obvious that reading the manual is the perfect approach for finding the correct information or at least a hint for finding the solution.
The false confidence or a lack of humbleness make people to forget how important is to read the documents. Understanding the documents is the next step, and is not simple indeed. In particular if the background is poor or the reader have preconceptions which alter the word meanings.
The failure is not an option. Despite this statement is quite pretentious is also the rule number zero of any decent DBA. The task failure, should this be a simple alter table or an emergency restore, is not acceptable. The database is the core of any application and therefore is the most important element of the infrastructure.
In order to achieve this impossible level, any task should be considered single shot.
I’ve already started writing the second volume of the database administration series.
The first volume was quite basic with enough information to be useful but not too much to scare people.
The second volume is strongly focused on the database administration and I decided to start it with a chapter explaining what it means to be a DBA.
Probably this will dissuade many people to start this exciting career.
So, here we go again.
Finally I finished the first volume of the PostgreSQL book administration.
The book is free to download on slideshare or, if you want the hard copy there is the button to order on lulu.com.
I’ll build an ebook version in the next days and I’ll make it available on amazon’s kindle and the kobo.
I hope this book will spread the knowledge on PostgreSQL.
Anyway, I’ve not finished. I’ve already started a second volume and a manual for the developers willing to learn the noble art of the SQL writing.
So finally PostgreSQL 9.4 has been released. This version introduces a new schema less type, the jsonb which joins the other fantastic features abused and misused by the developers all around the globe.
The DBA improvements in this release is much more interesting and can push seriously the adoption in the enterprises of this DBMS.
Alter system Finally is possible to change the postgresql.conf settings using the ALTER SYSTEM SET command.
Because an industrial action is taking place in Italy my flight was cancelled.
I’m not going to the Linux Day in person but, thanks Google, I should be able to talk.
PostgreSQL, The Big, The Fast and The Ugly from Federico Campoli
I’ll start Saturday 15.00 CEST.
