When sifting through a sql_trace file from Oracle version 12.2, I noticed a new wait event: ‘PGA memory operation’: The current documentation has no description for it. Let’s see what V$EVENT_NAME says: Well, that doesn’t help… Let’s look a bit deeper then, if Oracle provides no clue. Let’s start with the strace and sql_trace combination. …
This is the 4th post in a series of posts on PGA behaviour of Oracle. Earlier posts are: here (PGA limiting for Oracle 12), here (PGA limiting for Oracle 11.2) and the quiz on using PGA with AMM, into which this blogpost dives deeper. As laid out in the quiz blogpost, I have a database …
This is a series of blogposts on how the Oracle database makes use of PGA. Earlier posts can be found here (PGA limiting for Oracle 12) and here (PGA limiting for Oracle 11.2). Today a little wednesday fun: a quiz. What do you think will happen in the following situation (leave a response as comment …
This is the second part of a series of blogpost on Oracle database PGA usage. See the first part here. The first part described SGA and PGA usage, their distinction (SGA being static, PGA being variable), the problem (no limitation for PGA allocations outside of sort, hash and bitmap memory), a resolution for Oracle 12 …
This post is about memory management on the operating system level of an Oracle database. The first question that might pop in your head is: isn’t this a solved problem? The answer is: yes, if you use Oracle’s AMM (Automatic Memory Management) feature, which let’s you set a limit for the Oracle datababase’s two main …
This blogpost takes a look at the technical differences between Oracle database 19 RU 8 (july 2020) and RU 9 (october 2020). This gives technical specialists an idea of the differences, and gives them the ability to assess if the RU impacts anything. Functions This is a poor, yet one of the only ways to …
For the difference between Oracle database versions 12.2.0.1.191015 and 12.2.0.1.200114 this too follows the line of a low amount of differences. There have been two spare parameters that have been changed to named undocumented parameters, and no data dictionary changes. On the C function side, there have been a group of AWR functions that have …
It seems that the most eye-catching difference between Oracle database versions 19.5 and 19.4 is three underscore parameters spare parameters being changed to specifically named underscore parameters, two of them have a bug number in them which is not publicly visible. In v$sysstat/v$sesstat, a group of statistics are renamed from ‘OS %’ to ‘Server %’. …
In the article oracle memory troubleshooting using analysis on heap dumps I introduced heap_analyze.awk. The reason the tool exists is because I am using it myself. Therefore, I ran into additional things that I wanted the tool to do. I added some stuff, which is that significant, that I decided to make another blogpost to …
This blogpost is about analysing Oracle heap dumps. It is an extension to earlier work, Tanel Poder’s heap dump analyzer. So hat tip to Tanel, he’s done the hard work, I merely increased the presentation options. The heap analyser script that I wrote analyses Oracle heapdumps from the trace file that the dump was written …
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