How to improve TempDB performance?
1) TempDB file size and physical placement on harddrive can affect the performance of a system
2) Set the tempdb recovery model to simple
3) Do the capacity planning of the TempDB database and pre allocate the appropriate size to MDF files, which will improve performance for allocating size
4) Put TempDB on fast I/O System
5) Create as many tempdb data files by considering the number of cpu
6) make all the tempdb data file size same
Problem
How to troubleshoot suspect database problem? How to bring it back online? What are the do you need to perform once the database is online?
Solution
Step 1: Bring the database online using below script
USE Master
GO
— Determine the original database status
SELECT [Name], DBID, Status
FROM master.dbo.sysdatabases
GO
— Enable system changes
sp_configure ‘allow updates’,1
GO
RECONFIGURE WITH OVERRIDE
GO
— Update the database status
UPDATE master.dbo.sysdatabases
SET Status = 24
WHERE [Name] = ‘SuspectedDatabaseName’
GO
— Disable system changes
sp_configure ‘allow updates’,0
GO
RECONFIGURE WITH OVERRIDE
GO
— Determine the final database status
SELECT [Name], DBID, Status
FROM master.dbo.sysdatabases
GO
Step 2: Check for database corruption. This is very important step please execute it.
Step 3: To resolve the corruption issue, please execute below commands
Step 4: Repeat Step 2 to validate all the corruption occurred
The easiest solution to implement clustering in MySQL is DRBD and Heartbeat.
DRBD: The Distributed Replicated Block Device (DRBD) is a software-based, shared-nothing, replicated storage solution mirroring the content of block devices (hard disks, partitions, logical volumes etc.) between servers.
DRBD mirrors data
You can download DRDB from below site
memcached (pronunciation: mem-cash-dee.) is a general-purpose distributed memory caching system that was originally developed by Danga Interactive for LiveJournal, but is now used by many other sites. It is often used to speed up dynamic database-driven websites by caching data and objects in memory to reduce the number of times an external data source (such as a database or API) must be read. Memcached is distributed under a permissive free software license. Memcached lacks authentication and security features, meaning it should only be used on servers with a firewall set up appropriately. By default, memcached uses the port 11211. Among other technologies, it uses libevent. Memcached’s APIs provides a giant hash table distributed across multiple machines. When the table is full, subsequent inserts cause older data to be purged in least recently used (LRU) order. Applications using memcached typically layer memcached requests and additions into core before falling back on a slower backing store, such as a database. You can download memcached API from http://www.danga.com/memcached/
How to search error from SQL Server error log or SQL Server Agent Log?
We can find the particular error or information from error log by passing below parameters to XP_ReadErrorLog extended procedure.
EXEC sys.xp_readerrorlog @p1,@p2,@p3,@p4
@P1 = Value of error log file you want to read: 0 = current, 1 = Archive #1, 2 = Archive #2, etc…
@P2 = Log file type: 1 or NULL = error log, 2 = SQL Agent log
@P3 = Search string 1: String one you want to search for
@P4 = Search string 2: String two you want to search for to further refine the results
Please note all the parameters are optional.
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