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Improvements to LinearHistoryPageCacheTracer
* Significantly improve the print-out speed of large histories by buffering output to reduce the system call overhead on non-buffered PrintStreams. * Fix a couple of formatting errors where two events could end up on the same line. * Always record the PageSwapper in eviction events, even when the flush fails.
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community/io/src/test/java/org/neo4j/test/LinearHistoryPageCacheTracerTest.java
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| /** | ||
| * Copyright (c) 2002-2015 "Neo Technology," | ||
| * Network Engine for Objects in Lund AB [http://neotechnology.com] | ||
| * | ||
| * This file is part of Neo4j. | ||
| * | ||
| * Neo4j is free software: you can redistribute it and/or modify | ||
| * it under the terms of the GNU General Public License as published by | ||
| * the Free Software Foundation, either version 3 of the License, or | ||
| * (at your option) any later version. | ||
| * | ||
| * This program is distributed in the hope that it will be useful, | ||
| * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
| * GNU General Public License for more details. | ||
| * | ||
| * You should have received a copy of the GNU General Public License | ||
| * along with this program. If not, see <http://www.gnu.org/licenses/>. | ||
| */ | ||
| package org.neo4j.test; | ||
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| import org.junit.Ignore; | ||
| import org.junit.Test; | ||
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| import java.io.File; | ||
| import java.util.concurrent.ThreadLocalRandom; | ||
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| import org.neo4j.adversaries.RandomAdversary; | ||
| import org.neo4j.adversaries.fs.AdversarialFileSystemAbstraction; | ||
| import org.neo4j.graphdb.mockfs.EphemeralFileSystemAbstraction; | ||
| import org.neo4j.io.pagecache.PageCursor; | ||
| import org.neo4j.io.pagecache.PageSwapperFactory; | ||
| import org.neo4j.io.pagecache.PagedFile; | ||
| import org.neo4j.io.pagecache.impl.SingleFilePageSwapperFactory; | ||
| import org.neo4j.io.pagecache.impl.muninn.MuninnPageCache; | ||
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| import static org.neo4j.io.pagecache.PagedFile.PF_EXCLUSIVE_LOCK; | ||
| import static org.neo4j.io.pagecache.PagedFile.PF_SHARED_LOCK; | ||
|
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| public class LinearHistoryPageCacheTracerTest | ||
| { | ||
| @Ignore( "This test is only here for checking that the output from the LinearHistoryPageCacheTracer looks good. " + | ||
| "This is pretty subjective and requires manual inspection. Therefore there's no point in running it " + | ||
| "automatically in all our builds. Instead, run it as needed when you make changes to the printout code." ) | ||
| @Test | ||
| public void makeSomeTestOutput() throws Exception | ||
| { | ||
| RandomAdversary adversary = new RandomAdversary( 0.1, 0.1, 0.0 ); | ||
| adversary.setProbabilityFactor( 0.0 ); | ||
| EphemeralFileSystemAbstraction fs = new EphemeralFileSystemAbstraction(); | ||
| AdversarialFileSystemAbstraction afs = new AdversarialFileSystemAbstraction( adversary, fs ); | ||
| PageSwapperFactory swapperFactory = new SingleFilePageSwapperFactory( afs ); | ||
| int maxPages = 10; | ||
| int cachePageSize = 8192; | ||
| LinearHistoryPageCacheTracer tracer = new LinearHistoryPageCacheTracer(); | ||
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| File fileA = new File( "a" ); | ||
| File fileB = new File( "b" ); | ||
| fs.open( fileA, "rw" ).close(); | ||
| fs.open( fileB, "rw" ).close(); | ||
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| try ( MuninnPageCache cache = new MuninnPageCache( swapperFactory, maxPages, cachePageSize, tracer ); | ||
| PagedFile pfA = cache.map( fileA, 8192 ); | ||
| PagedFile pfB = cache.map( fileB, 8192 ) ) | ||
| { | ||
| adversary.setProbabilityFactor( 1.0 ); | ||
| ThreadLocalRandom rng = ThreadLocalRandom.current(); | ||
| for ( int i = 0; i < 200; i++ ) | ||
| { | ||
| try | ||
| { | ||
| boolean readOnly = rng.nextBoolean(); | ||
| int flags = readOnly ? PF_SHARED_LOCK : PF_EXCLUSIVE_LOCK; | ||
| int startPage = rng.nextInt( 0, 10 ); | ||
| int iterations = rng.nextInt( 1, 10 ); | ||
| PagedFile file = rng.nextBoolean()? pfA : pfB; | ||
| try ( PageCursor cursor = file.io( startPage, flags ) ) | ||
| { | ||
| for ( int j = 0; j < iterations; j++ ) | ||
| { | ||
| cursor.next(); | ||
| Thread.sleep( 1 ); | ||
| if ( !readOnly ) | ||
| { | ||
| for ( int k = 0; k < 8192 / 4; k++ ) | ||
| { | ||
| cursor.putInt( rng.nextInt() ); | ||
| } | ||
| } | ||
| } | ||
| } | ||
| if ( rng.nextDouble() < 0.1 ) | ||
| { | ||
| file.flush(); | ||
| } | ||
| else if ( rng.nextBoolean() ) | ||
| { | ||
| cache.flush(); | ||
| } | ||
| } | ||
| catch ( Throwable ignore ) | ||
| { | ||
| } | ||
| } | ||
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| // Don't fail when we close or unmap. | ||
| adversary.setProbabilityFactor( 0.0 ); | ||
| } | ||
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| tracer.printHistory( System.out ); | ||
| } | ||
| } |