Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

Krum Tsvetkov (SAP)

Andrew Johnson (IBM)

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

Krum Tsvetkov, Andrew Johnson 2

Memory Analyzer overview

Works with heap dumps – post-mortem analysis UI and programmatic access to data in the heap dumps Automatic problem recognition Extendable

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

Krum Tsvetkov, Andrew Johnson 3

Demo

Introduction to Memory Analyzer

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

Krum Tsvetkov, Andrew Johnson 4

Introduction to extending MAT

Why extend MAT? To save time doing the same thing repeatedly To help others use the same technique as you To do things not possible from the GUI To build in application specific logic

Examples Eclipse bundle explorer – shown as a tree (provided with MAT) JRuby (recent contribution to MAT)

How to extend MAT MAT provides a set of Eclipse extension points User writes an extension plug-in MAT provides an API for reading the data from a dump

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Name Resolver

Used to give meaningful descriptions of objects Text result (similar to a toString()) Useful for 'Group by Value' query Extension point: org.eclipse.mat.nameResolver

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Implement a Name Resolver

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Query

Used for exploring dumps or detailed analysis May interact with existing queries (context menus) Integrated into MAT’s menus Extension point: org.eclipse.mat.api.query

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Implement a Query

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Results from a Query

IResult

ObjectList

(a

tree

)

ListResult

(a

tabl

e)

Com

posi

tion

of

resu

lts in

HT

ML

Histogram

(a

tabl

e)

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Using a Predefined Result

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Request Resolver

Used to identify what a thread was doing

Appears in the leak suspects report

Extension point - org.eclipse.mat.api.requestResolver

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

Krum Tsvetkov, Andrew Johnson 21

Implement a Request Resolver

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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Other extension points

Reports - org.eclipse.mat.report.report HTML results of queries – also used for batch mode

Thread resolver – additional thread data such as native stacks Ticket resolver – can identify appropriate routing for problem

Based on classes and classloaders of problem objects

Rendering – org.eclipse.mat.api.renderer Additional to HTML and CSV

Trigger heap dump – org.eclipse.mat.api.heapDumpProvider For new VM types

Parser – for new dump types and VMs, such as for Jikes RVM Snapshot factory – org.eclipse.mat.api.factory

Unlikely to use this as replaces whole snapshot

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

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In Summary, MAT Offers …

Helpful memory analysis features out-of-the-box API for extracting data Application specific analysis can be added as extensions

Distilling Heap Dumps: a Guide to Using and Extending Memory Analyzer

Krum Tsvetkov, Andrew Johnson 24

Thank You!

Memory Analyzer @ Eclipse: http://www.eclipse.org/mat

Wiki page for extending Memory Analyzer:http://wiki.eclipse.org/MemoryAnalyzer/Extending_Memory_Analyzer

Forum: http://www.eclipse.org/forums/eclipse.memory-analyzer

Blogs:http://dev.eclipse.org/blogs/memoryanalyzer