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What are the causes of query failures in databases?

For a database, the query returns the correct result in 99% of cases, but in 1% of cases it returns the wrong output. What could be the possible reasons?

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There are several reasons why a query returns an “incorrect” or “expected” result set:

  • "Invalid" data has been added to the database / table.
  • The request reads uncommitted or phantom records (see database isolation levels)
  • Your data has not yet been indexed (in the case of a full-text index), or the full-text service rebuilds the index
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, , 500 000 . UserA Transact-SQL, ( ) . 100 000 , UserB Transact-SQL, . 100 001 . 200 000- , UserC Transact-SQL, . 200,001, Database Engine . , 500 000- , UserA , UserB UserC , 1. Database Engine 100 000, UserB . UserC , 200 000. . :

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cache, synchronization / duplication, lack of resources, etc.

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