Insane DBA...

Some decisions are actually not taken by the optimizer. I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there. We started to experience a performance problem with an SQL query which we cannot change the software code and tried to find a solution in solely the database layer.  SQL query was a sophisticated one, but the problem can be summarized with the short one below. Here is the plan output. Products table was a large table exceeding 50 Gb size and query's execution time was 180 - 200 seconds.  Query was searching in PRODUCTS table for the HTML_CONTENT with not null records, but for all rows,  HTML_CONTENT column values were null, and as this column is not indexed, the query was performing a full ...

No more frequent remastering of objects. I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there. As default value of "_gc_policy_minimum"(formerly known as _gc_affinity_minimum) is quite low for busy environments, Those who are setting this parameter to 15000 according to the Best Practices and Recommendations for RAC databases with SGA size over 100GB (Doc ID 1619155.1) , I have good news for you.  From 19.20 (19c DBRU JUL '23) on, You may reset it to its default value.  Due to internal bug 34729755, 15000 is the new default in 23c, 19c DBRU JUL '23, and 19c ADB.  DBAs having compulsive tuning disorder like me won't have to tune this parameter any more in those releases or later. According to the  DRM - Dynamic Resource management (Doc ID 390483.1) , DRM attribu...

Bonus Step - What a Wonderful Patch (Patching Tips) I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there. Failure to patch your database software may lead to losses of data that can cost money and reputation. That is the point of security. Also there are many other benefits, including adding features, and fixing bugs that make your applications run slow or not work as intended.   Every database administrator should have a patching strategy that suits up with his/her organization. I will share my tips that can also be useful for others and may not be suitable for some. Because every organization has their own constraints and unique environment. Generally Applicable  * First know your database environment and identify all the features you are using actively. Kno...

Step 5 - Another one Patches the Dust. (Cleaning Old Oracle Homes) I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there. After you patch your database servers grid and database homes whether using out-of-place method or fleet patching method, you should remove the old Oracle Homes.  As a precautionary measure, I keep old Oracle Homes at least 15 days and once i am comfortable with the new ones, then i remove old ones. Removing old Oracle Grid Infrastructure Home with deinstall command:  The deinstall command detects cluster nodes, displays a short summary, asks for confirmation, operates on all nodes and warns you to run root.sh on all nodes, and usually leaves some leftovers. I also remove the old directory. After deinstallation, old grid home is flagged as deleted ...

Step 4 - Patchin' Alive. (Oracle RAC Database Patching using Fleet Maintenance) I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there.   I will patch all my database servers database software from 19.16 to 19.20. As there are more than 20 servers to patch, we will use fleet patching. First, I have patched a 2-node cluster database homes by using out of place (OOP) patching methodology through runInstaller in silent mode in Step 2 - Patch My Breath Away(DB OOP Patching) . Now I will use patched an Oracle RAC database home to create a gold image for fleet patching of all Oracle RAC database homes. Some useful references:       *  Primay Note for Database Patching Using Enterprise Manager 13c Cloud Control Fleet Maintenance (Doc Id 2435251.1)   ...

Step 3 - Patching in the Deep. (Grid Patching using Fleet Maintenance) I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there.        I will patch all my database servers grid infrastructure from 19.16 to 19.20. As there are more than 20 servers to patch, we will use fleet patching. First i have patched a 2 node cluster grid infrastructure by using out of place ( OOP ) patching  methodology through gridSetup.sh in silent mode in Step 1 - Patch Me If You Can (Grid OOP Patching)      Now i will use patched grid homes to create a gold image for fleet patching of all grid homes. Some useful references:      *  Primay Note for Database Patching Using Enterprise Manager 13c Cloud Control Fleet Maintenance (Doc Id 2435251.1)   ...

Step 2 - Patch My Breath Away. (DB OOP Patching) I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there. I will patch all my database servers database software from 19.16 to 19.20. As there are more than 20 servers to patch, we will use fleet patching. First, I will patch a 2-node cluster database homes by using out-of-place (OOP) patching methodology through runInstaller in silent mode. Later, I will use patched database homes to create a gold image for fleet patching of all database homes. Setup List:  * Database 19.3 Base Release (LINUX.X64_193000_db_home.zip)  * Database 19.20 RU (p35320081_190000_Linux-x86-64.zip)  * Grid 19.20 August MRP involves DB August MRP. (p35656840_1920000DBRU_Linux-x...

Step 1 - Patch Me If You Can. (Grid OOP Patching) I’ve moved my blog from https://insanedba.blogspot.com to https://dincosman.com Please update your bookmarks and follow/subscribe at the new address for all the latest updates and content. More up-to-date content of this post may be available there. I will patch all my database servers grid infrastructure from 19.16 to 19.20. As there are more than 20 servers to patch, we will use fleet patching. First i will patch a 2 node cluster grid infrastructure by using out of place ( OOP ) patching  methodology through gridSetup.sh in silent mode.  Doc ID 2853839.1   and Patching Oracle Grid Infrastructure 19c using out-of-place SwitchGridHome video by Daniel Overby Hansen   can be used a reference.  Later i will use patched grid homes to create a gold image for fleet patching of all grid homes. Setup List:  * Grid 19.3 Base Release (LINUX.X64_193000_grid_home.zip)  * Grid 19.20 RU (p35319490_190...