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Database Administrator's Guide

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COMPATIBILITY DIRECT_IO

COMPATIBILITY DIRECT_IO

The FairCom Server for Solaris uses O_DSYNC synchronous writes for the transaction logs when the COMPATIBILITY SYNC_LOG or COMPATIBILITY LOG_WRITETHRU configuration options are specified in the server configuration file.

Furthermore, it is expected the O_DSYNC writes are more efficient than O_SYNC writes. The FairCom Server uses O_DSYNC on systems that define this file open mode and uses O_SYNC on systems that do not define the O_DSYNC file open mode.

COMPATIBILITY DIRECT_IO, is available to revert to the previous behavior of direct I/O.

When the FairCom Server starts up, it writes either the message "Transaction logs using direct I/O." or "Transaction logs using synchronous I/O." to CTSTATUS.FCS to indicate which method of synchronous writes is in use. If neither COMPATIBILITY SYNC_LOG nor COMPATIBILITY LOG_WRITETHRU is specified in ctsrvr.cfg, neither of these messages is written to CTSTATUS.FCS as in that case the server performs asynchronous writes that are flushed by a separate call.

Default: OFF

Also See

COMPATIBILITY LOG_WRITETHRU

COMPATIBILITY SYNC_LOG

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