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
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
Create a Clone DB from Backup on the Same Server (or remote) Mustafa, 2021-04-262021-04-27 Hi, I wanted to create a post series about cloning/duplicating database on the same or remote servers. There are so many options and combinations about this like rman duplicate database with/without target/source db connection, rman restore using backups, ASM to OS or OS to ASM, same server or remote server,… Continue Reading
ORA-24244: invalid host or port for access control list (ACL) assignment Mustafa, 2020-12-24 Hello everyone, So you wanted to migrate your ACLs to another database or you are trying to add a new acl entity but you got ORA-24244. There are many reasons for that error unfortunately. I wish Oracle provides us more detail about what is the error but I wanted to… Continue Reading
export import ACL & ORA-24244 error during import Mustafa, 2020-12-16 Hello everyone, it’s been a while since my last post. So, I wanted to write about export and import ACL privileges. They always become a pain (at least for me). after 12c, Oracle introduce us a new and easy way of ACL copying from db to db. export&import. so here… Continue Reading
Direct Path Insert &/vs Conventional Insert Mustafa, 2020-10-27 Hi there, I couldn’t write anything for a while. Those days were busy. So I would talk to about direct path insert and conventional insert. Many people think that they are using “direct path insert” when used sqlldr utility but they are not. it is easy to confused batch insert… Continue Reading
Flashback Data Archive Problems! Mustafa, 2020-09-102020-09-10 Hi, if you don’t know about flashback data archive you can check this post first: https://mustafakalayci.me/2019/03/02/goodbye-log-triggers-welcome-flashback-data-archive/ I mentioned about flashback data archive (FDA) in that post and really flattered it. Well, maybe I shouldn’t! FDA is really fast dml tracking method but thanks to Peter Schlaeger, I noticed some potential… Continue Reading