How to Restore Dropped PDB Mustafa, 2022-02-04 Hi, it seems easy, right? Well, not that much but not that hard either. if you drop a pdb in a cdb, you cannot restore it using current database because when you drop the pdb, all information about the pdb is lost. So, what is the solution? you need a… Continue Reading
CONTAINER_DATA for Common Users Mustafa, 2022-01-062022-01-06 Hello Everyone (if anyone reading this 🙂 ), it has been a long year and I am glad it is over. As always, we hope the for “a time of period” like new year, birthday etc etc but hope is the only thing that we can hold on. I hope… Continue Reading
How to Demonize Apex V Function! Mustafa, 2021-10-312021-11-04 Hi, Answer of the question in the subject is “Using too much V in SQL statements”. Let’s see why and what should you do. First things first, I am NOT a APEX developer. I am a DBA and Database Developer but some of my clients are using APEX and I… Continue Reading
Hierarchical Blocking Session List Mustafa, 2021-10-19 Hi, Today, I needed to list all blocking sessions hierarchically. As you know, all information about sessions (and blocking sessions) are in gv$session (or just v$session if you are using single instance) view. I wanted to see who is blocking who and blocker at the top. you can write simple… Continue Reading
Subquery Caching Mustafa, 2021-10-172021-11-19 Hi, I want to talk about very sweet performance “trick”. I love when I do something small and gain a lot 🙂 Today, I will demonstrate subquery caching in Oracle and try to explain how it works and it’s limitations. Probably, you are using some plsql functions in your select… Continue Reading
Why should you use PLSQL_OPTIMIZE_LEVEL as 3 Mustafa, 2021-10-08 Hi, As you know PLSQL_OPTIMIZE_LEVEL parameter is used to optimize the codes while compiling them and it is really important. By default it’s value is 2 but you can increase it to 3 and you should, here is why. before begin, this is an extension for this post: https://mustafakalayci.me/2020/06/26/performance-gain-of-nocopy-parameters/ Very… Continue Reading
ORA-04036: PGA memory used by the instance exceeds PGA_AGGREGATE_LIMIT While Compiling a Huge PLSQL package Mustafa, 2021-09-28 Hello everyone, Lately, I faced with an interesting ORA-04036 errors at one of my clients’ development database. My notification modules alerted me about ORA-04036 error and I was just started to investigate trace files (and saw a package name frequently) and one of the developer sent me an email about… Continue Reading
Enable Unified Audit on Linux and Windows Mustafa, 2021-09-08 Hi, As you know, since 12c Oracle introduce Unified Auditing which has much more capabilities than standard auditing. Creating policies, audit conditions, top level auditing etc. By default Oracle uses “mixed” mode which allows you to run unified auditing commands and standard auditing. you can check if you are using… Continue Reading
Blockchain vs Immutable tables Mustafa, 2021-08-202021-10-26 Hi, as you know 21c is here for linux and some new features are (as always) pretty exciting. two of them are Blockchain and Immutable tables. Let’s explain and test. first of all, those are new features for 21c but they are backported to 19c. at 19.10 you are able… Continue Reading