• DBA

    The log scan number passed to log scan in database is not valid. This error may indicate data corruption

    Database went into suspect mode database corruption One of our servers got migrated from one data center to other data center using third party tool called Zerto. After migration two databases went into suspect mode. Errors in the log: The log scan number (40359:103:2) passed to log scan in database <db name> is not valid. This error may indicate data corruption or that the log file (.ldf) does not match the data file (.mdf). If this error occurred during replication, re-create the publication. Otherwise, restore from backup if the problem results in a failure during startup During undoing of a logged operation in database <db name>  , an error occurred…

  • Performance

    MSSQL Query running fast in production and slow in non-production

     Query running fast in production and slow in non-production I have asked to look one of the queries that run fast in production and slow in non-production. Question asked – how long it took to complete the results. It is about 1.50 minutes in non-production, but in production it completed less than 5 seconds. Got the code and run myself in SSMS to compare the plan, since it will finish 1.50 minutes. It quickly showed estimated number of rows are totally different. This could be either out of stats or data skew.   I just checked the last stats update and updated the stats that fixed the issue. You can…

  • DBA

    MS SQL server remote DBA training course topics Chennai India

    Microsoft SQL server training course topics:   Overview of IT environment with daily DBA activity and health check A brief of history (RDBMS & DBMS) SQL server internal architecture SQL server overview (Editions) SQL Installation overview (System DBs) Review of new features Transact -SQL overview Normalization TABLES AND CONSTRAINTS Standard data types Tables and columns in SQL server Objects, Tables and columns in T-SQL Modifying tables and columns Database diagram architecture Constrains TRANSACT SQL QUIERES Querying SQL server tables SQL and transact SQL Using the select statement Transact SQL built-in function Summary queries Sub queries MERGING DATA WITH JOINS&UNIONS Working with inner joins Using left outer joins Multiplying data with…

  • DBA

    DR Test Backup and restore drill test

    Overview: There was requirement from business to test live server backup into DR server every month / week, not a completed DR. It was about 30+ databases with total of 500 GB. Steps: Add net use command in sp_DatabaseRestore stored procedure Share backup folder path in source server “\” Run the find the recent backup script on source server Script out and run it on target server where you have created sp_DatabaseRestore Run the restore command in SSMS or SQL agent job. Test Restore with execute N parameter and make sure everything is correct and run with Y.   I have started using Ola Hallengren’s maintenance script and searched for…