CODEWITHSUNDEEP
sql-serverthread-safetyidentity
raf
raf

Reputation: 1141

Is a SQL Server IDENTITY auto-incremented field thread-safe?

I've some questions regarding the SQL Server IDENTITY auto-incremented column.

Does someone know if that field is thread-safe?

Can I use SQL Server IDENTITY column in a multitask application that attempt to parallel insert some records with an IDENTITY auto-incremented column?

Do you have any docs link about that?

Upvotes: 2

Views: 1099

Answers (1)

usr
usr

Reputation: 171206

It is thread-safe in the sense that every number will be handed out at most once. Numbers can be skipped, though.

This is a well-accepted fact. SQL Server would be garbage if this was not so. It is the point of identity fields to hand out unique values.

Be aware that you can circumvent these guarantees by reseeding the column. That way you can have it hand out whatever you want.

Also note, that an IDENTITY constraint does not enforce uniqueness of values in that column.

Upvotes: 3

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