# Berkeley DB Reference Guide: Release 3.1: log file pre-allocation
Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++

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Berkeley DB Reference Guide:
  Upgrading Berkeley DB Applications

### Release 3.1: log file pre-allocation

This change only affects Win/32 applications.

On Win/32 platforms Berkeley DB no longer pre-allocates log files. The problem was a noticeable performance spike as each log file was created. To turn this feature back on, search for the flag DB_OSO_LOG in the source file log/log_put.c and make the change described there, or contact us for assistance.

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