Mercurial > hg > blitz_stable

annotate src/org/dancres/blitz/config/Persistent.java @ 0:3dc0c5604566

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Initial checkin of blitz 2.0 fcs - no installer yet.
author Dan Creswell <dan.creswell@gmail.com>
date Sat, 21 Mar 2009 11:00:06 +0000
parents
children cd96fcac1487
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3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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1 package org.dancres.blitz.config;
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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2
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Dan Creswell <dan.creswell@gmail.com>
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3 /**
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Dan Creswell <dan.creswell@gmail.com>
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4 Configures Blitz to be maximally durable with all operations being recorded
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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5 on disk immediately they are commited.
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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6
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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7 @todo Add MAX_LOGS_BEFORE_SYNC disable
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Dan Creswell <dan.creswell@gmail.com>
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8 */
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9 public class Persistent extends PersistentBase {
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10
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11 private boolean useConcurrentBatcher;
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12 private int theBatchWriteWindowSize;
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13
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Dan Creswell <dan.creswell@gmail.com>
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14 /**
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15 @param shouldReset specifies whether to reset the ObjectOutputStream
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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16 used for logging. This is a performance vs memory tradeoff
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17
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18 @param shouldClean specifies whether old log files and snapshots should
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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19 be cleaned up or left for archiving.
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Dan Creswell <dan.creswell@gmail.com>
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20
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21 @param aBatchWriteWindowSize specifies a batch-write window for logging.
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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22 Set this to zero to disable batching. Batch-writing can reduce the
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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23 number of forced flushes to disk whilst increasing the amount of data
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24 written with each flush. This has a positive effect on throughput
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25 under concurrent load. Time is specified in ms, first thread into
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26 barrier waits this amount of time for other writers. Other writers
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27 entering the barrier are now blocked until the first entrant commits all
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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28 writes to log.
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29
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30 @param useConcurrent should increase log throughput by allowing the
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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31 next batch to form whilst the current batch is being written to log.
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32
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33 @param aMaxLogsBeforeSync is the maximum number of log entries before
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34 a checkpoint is forced.
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35
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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36 @param aLogBufferSize especially useful when doing batching.
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37 All commands are rendered to the buffer before going to disk in one
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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38 large block. Without the buffer, each command will trickle to disk as a
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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39 small update which isn't good for throughput!
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40 */
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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41 public Persistent(boolean shouldReset, boolean shouldClean,
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42 int aBatchWriteWindowSize, boolean useConcurrent,
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
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43 int aMaxLogsBeforeSync, int aLogBufferSize) {
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44
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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45 super(shouldReset, shouldClean, aLogBufferSize, aMaxLogsBeforeSync);
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46 useConcurrentBatcher = useConcurrent;
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47 theBatchWriteWindowSize = aBatchWriteWindowSize;
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Dan Creswell <dan.creswell@gmail.com>
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48 }
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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49
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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50 public boolean useConcurrentWriteBatcher() {
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51 return useConcurrentBatcher;
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52 }
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53
3dc0c5604566 Initial checkin of blitz 2.0 fcs - no installer yet.
Dan Creswell <dan.creswell@gmail.com>
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54 public int getBatchWriteWindowSize() {
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55 return theBatchWriteWindowSize;
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56 }
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57 }