Category: My SQL
-
About Us
At CLOTA Technology, we provide innovative solutions in database technologies, web development, cloud maintenance, and software support to help businesses achieve their goals. Our services include expert SQL and NoSQL database design, implementation, and maintenance with certified DBAs boasting 15+ years of experience. We specialize in custom website and app creation, cloud services for migrations,…
-
Deadlock
Deadlock is a situation where two or more transactions wait for completion of each-other for resources but none of them completes. or Deadlock occur between the transactions when 2 or more translations permanently block each-other in such a ways that each transaction having a lock on the resource where the other tasks are trying to…
-
Physical Database Architecture
Database Files SQL Server maps a DB to a set of OS files visible to SQL Server. We can create 32767 files in a DB. First page (Page 0) of every DB file is FHP file header page. Second page (Page 1) of every DB file PFS (page free space) page. PFS uses 1 byte for each…
-
Delete vs Truncate
Its a common interview question which people like to ask to know your understanding on RDMS concepts. I too few times encountered the question in interviews. Pleases don’t ask me interview result. Haha ha… DELETE: 1. DELETE is a DML Command. 2. DELETE statement is executed using a row lock, each row in the table…
-
Pages in Database
Boot Page Every DB has only one boot page. Boot page stores DB configuration information. It can find in page # 9 of the first DB data file. Bulk Changed Map (BCM) Page BCM page keep track of the extends which has modified by bulked-logged operations. Log backup thread reads this page and get the extends…
-
Wait Types in SQL Server
-
Phases of Recovery in Database
At the time of SQL instance reboot or start, database goes in the three phases of recovery… 1. Analysis Phase of recovery 2. Redo Phase of recovery 3. Undo Phase of recovery 1. Analysis Phase of recovery This phase does two things… First, construct a Dirty Page Table (DPT) Second, construct an Active Transaction Table. Dirty Page Table consist…
-
SQL Server Memory Architecture
There are four major components of SQL memory architecture… 1. Memory Broker2. Memory Object3. Memory Clerk4. Memory Node In short, BOCN. (For remember it “Boy Of Cartoon-Network”) 1. Memory Broker Purpose of Memory Broker is to provide a centralized mechanism to distribute/control memory the allocation made by each component in SQL Server. Note: Memory brokers do…
-
Mirroring Witness getting disappear from Mirroring Setup…
Recently we have faced one issue where DB mirroring witness getting disappear from mirroring setup. This is happening once Principal get down or SQL services restarts. In the case, we found DB fail-over is also is not working. Once the Principal server come online the DB start serving role as Principal DB and get in…