Mercurial > hg > blitz_condensed
view src/org/dancres/blitz/config/Persistent.java @ 34:6f68e94c1fb8 default tip
Add CondensedStats monitoring utility, equivalent to vmstat
author | Dominic Cleal <dominic-cleal@cdo2.com> |
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date | Thu, 05 Aug 2010 11:07:25 +0100 |
parents | a77f0a9ed93c |
children |
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package org.dancres.blitz.config; /** Configures Blitz to be maximally durable with all operations being recorded on disk immediately they are commited. @todo Add MAX_LOGS_BEFORE_SYNC disable */ public class Persistent extends PersistentBase { private boolean dontUseExpLog; private long theBatchWriteWindowSizeMs; private int theBatchWriteWindowSizeNs; /** @param shouldReset specifies whether to reset the ObjectOutputStream used for logging. This is a performance vs memory tradeoff @param shouldClean specifies whether old log files and snapshots should be cleaned up or left for archiving. @param aBatchWriteWindowSize specifies a batch-write window for logging. Set this to zero to disable batching. Batch-writing can reduce the number of forced flushes to disk whilst increasing the amount of data written with each flush. This has a positive effect on throughput under concurrent load. Time is specified in ms, first thread into barrier waits this amount of time for other writers. Other writers entering the barrier are now blocked until the first entrant commits all writes to log. @param noUseExpLog avoid using optimistic logger which should increase log throughput by allowing an optimistic flushing strategy but may still contain bugs @param aMaxLogsBeforeSync is the maximum number of log entries before a checkpoint is forced. @param aLogBufferSize especially useful when doing batching. All commands are rendered to the buffer before going to disk in one large block. Without the buffer, each command will trickle to disk as a small update which isn't good for throughput! */ public Persistent(boolean shouldReset, boolean shouldClean, int aBatchWriteWindowSize, boolean noUseExpLog, int aMaxLogsBeforeSync, int aLogBufferSize) { super(shouldReset, shouldClean, aLogBufferSize, aMaxLogsBeforeSync); dontUseExpLog = noUseExpLog; theBatchWriteWindowSizeMs = aBatchWriteWindowSize; } public boolean dontUseExperimentalBatcher() { return dontUseExpLog; } public long getBatchWriteWindowSizeMs() { return theBatchWriteWindowSizeMs; } public int getBatchWriteWindowSizeNs() { return theBatchWriteWindowSizeNs; } public Persistent(boolean shouldReset, boolean shouldClean, long aBatchWindowSizeMs, int aBatchWindowSizeNs, boolean noUseExpLog, int aMaxLogsBeforeSync, int aLogBufferSize) { super(shouldReset, shouldClean, aLogBufferSize, aMaxLogsBeforeSync); dontUseExpLog = noUseExpLog; theBatchWriteWindowSizeMs = aBatchWindowSizeMs; theBatchWriteWindowSizeNs = aBatchWindowSizeNs; } }