Not necessarily. If it is just a query (select), rather than an update, delete, or insert, then locks might not be involved. I meant the term "transaction" to be technical, that is possibily involving a lock. So it depends on the type of transaction, and the database. Some databases require table locking and some row locking. Some databases have different requirements depending on the table type (MySQL comes to mind).

This still assumes that the jobs are running concurrently. Are they?
It might also help if we knew the OS and which database product.

In reply to Re^3: Perl concurrent access by cdarke
in thread Perl concurrent access by TienLung

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