296 lines
8.8 KiB
Groff
296 lines
8.8 KiB
Groff
.\" Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.
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.\" DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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.\"
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.\" This code is free software; you can redistribute it and/or modify it
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.\" under the terms of the GNU General Public License version 2 only, as
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.\" published by the Free Software Foundation.
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.\"
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.\" This code is distributed in the hope that it will be useful, but WITHOUT
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.\" ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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.\" FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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.\" version 2 for more details (a copy is included in the LICENSE file that
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.\" accompanied this code).
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.\"
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.\" You should have received a copy of the GNU General Public License version
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.\" 2 along with this work; if not, write to the Free Software Foundation,
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.\" Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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.\"
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.\" Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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.\" or visit www.oracle.com if you need additional information or have any
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.\" questions.
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.\"
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.\" Automatically generated by Pandoc 2.3.1
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.\"
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.TH "JFR" "1" "2023" "JDK 20\-ea" "JDK Commands"
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.hy
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.SH NAME
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.PP
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jfr \- parse and print Flight Recorder files
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.SH SYNOPSIS
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.PP
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To print the contents of a flight recording to standard out:
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.PP
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\f[CB]jfr\f[R] \f[CB]print\f[R] [\f[I]options\f[R]] \f[I]file\f[R]
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.PP
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To print metadata information about flight recording events:
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.PP
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\f[CB]jfr\f[R] \f[CB]metadata\f[R] \f[I]file\f[R]
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.PP
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To assemble chunk files into a flight recording file:
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.PP
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\f[CB]jfr\f[R] \f[CB]assemble\f[R] \f[I]repository\f[R] \f[I]file\f[R]
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.PP
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To disassemble a flight recording file into chunk files:
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.PP
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\f[CB]jfr\f[R] \f[CB]disassmble\f[R] [\f[I]options\f[R]] \f[I]file\f[R]
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.PP
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To view the summary statistics for a flight recording file:
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.PP
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\f[CB]jfr\f[R] \f[CB]summary\f[R] \f[I]file\f[R]
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.TP
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.B \f[I]options\f[R]
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Optional: Specifies command\-line options separated by spaces.
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See the individual subcomponent sections for descriptions of the
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available options.
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.RS
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.RE
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.TP
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.B \f[I]file\f[R]
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Specifies the name of the target flight recording file
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(\f[CB]\&.jfr\f[R]).
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.RS
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.RE
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.TP
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.B \f[I]repository\f[R]
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Specifies the location of the chunk files which are to be assembled into
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a flight recording.
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.RS
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.RE
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.SH DESCRIPTION
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.PP
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The \f[CB]jfr\f[R] command provides a tool for interacting with flight
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recorder files (\f[CB]\&.jfr\f[R]).
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The main function is to filter, summarize and output flight recording
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files into human readable format.
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There is also support for merging and splitting recording files.
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.PP
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Flight recording files are created and saved as binary formatted files.
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Having a tool that can extract the contents from a flight recording and
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manipulate the contents and translate them into human readable format
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helps developers to debug performance issues with Java applications.
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.SS Subcommands
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.PP
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The \f[CB]jfr\f[R] command has several subcommands:
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.IP \[bu] 2
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\f[CB]print\f[R]
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.IP \[bu] 2
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\f[CB]summary\f[R]
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.IP \[bu] 2
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\f[CB]assemble\f[R]
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.IP \[bu] 2
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\f[CB]disassemble\f[R]
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.IP \[bu] 2
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\f[CB]metadata\f[R]
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.SS \f[CB]jfr\ print\f[R] subcommand
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.PP
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Use \f[CB]jfr\ print\f[R] to print the contents of a flight recording file
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to standard out.
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The syntax is:
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.PP
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\f[CB]jfr\ print\f[R] [\f[CB]\-\-xml\f[R]|\f[CB]\-\-json\f[R]]
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[\f[CB]\-\-categories\f[R] <\f[I]filters\f[R]>] [\f[CB]\-\-events\f[R]
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<\f[I]filters\f[R]>] [\f[CB]\-\-stack\-depth\f[R] <\f[I]depth\f[R]>]
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<\f[I]file\f[R]>
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.PP
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where:
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.TP
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.B \f[CB]\-\-xml\f[R]
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Print the recording in XML format
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.RS
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.RE
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.TP
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.B \f[CB]\-\-json\f[R]
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Print the recording in JSON format
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.RS
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.RE
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.TP
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.B \f[CB]\-\-categories\f[R] <\f[I]filters\f[R]>
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Select events matching a category name.
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The filter is a comma\-separated list of names, simple and/or qualified,
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and/or quoted glob patterns
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.RS
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.RE
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.TP
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.B \f[CB]\-\-events\f[R] <\f[I]filters\f[R]>
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Select events matching an event name.
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The filter is a comma\-separated list of names, simple and/or qualified,
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and/or quoted glob patterns
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.RS
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.RE
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.TP
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.B \f[CB]\-\-stack\-depth\f[R] <\f[I]depth\f[R]>
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Number of frames in stack traces, by default 5
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.RS
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.RE
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.TP
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.B <\f[I]file\f[R]>
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Location of the recording file (\f[CB]\&.jfr\f[R])
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.RS
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.RE
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.PP
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The default format for printing the contents of the flight recording
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file is human readable form unless either \f[CB]xml\f[R] or \f[CB]json\f[R]
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is specified.
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These options provide machine\-readable output that can be further
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parsed or processed by user created scripts.
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.PP
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Use \f[CB]jfr\ \-\-help\ print\f[R] to see example usage of filters.
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.PP
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To reduce the amount of data displayed, it is possible to filter out
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events or categories of events.
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The filter operates on the symbolic name of an event, set by using the
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\f[CB]\@Name\f[R] annotation, or the category name, set by using the
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\f[CB]\@Category\f[R] annotation.
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If multiple filters are used, events from both filters will be included.
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If no filter is used, all the events will be printed.
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If a combination of a category filter and event filter is used, the
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selected events will be the union of the two filters.
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.PP
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For example, to show all GC events and the CPULoad event, the following
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command could be used:
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.PP
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\f[CB]jfr\ print\ \-\-categories\ GC\ \-\-events\ CPULoad\ recording.jfr\f[R]
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.PP
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Event values are formatted according to the content types that are being
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used.
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For example, a field with the \f[CB]jdk.jfr.Percentage\f[R] annotation
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that has the value 0.52 is formatted as 52%.
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.PP
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Stack traces are by default truncated to 5 frames, but the number can be
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increased/decreased using the \f[CB]\-\-stack\-depth\f[R] command\-line
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option.
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.SS \f[CB]jfr\ summary\f[R] subcommand
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.PP
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Use \f[CB]jfr\ summary\f[R] to print statistics for a recording.
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For example, a summary can illustrate the number of recorded events and
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how much disk space they used.
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This is useful for troubleshooting and understanding the impact of event
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settings.
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.PP
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The syntax is:
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.PP
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\f[CB]jfr\ summary\f[R] <\f[I]file\f[R]>
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.PP
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where:
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.TP
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.B <\f[I]file\f[R]>
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Location of the flight recording file (\f[CB]\&.jfr\f[R])
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.RS
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.RE
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.SS \f[CB]jfr\ metadata\f[R] subcommand
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.PP
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Use \f[CB]jfr\ metadata\f[R] to view information about events, such as
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event names, categories and field layout within a flight recording file.
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The syntax is:
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.PP
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\f[CB]jfr\ metadata\f[R] <\f[I]file\f[R]>
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.PP
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where:
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.TP
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.B <\f[I]file\f[R]>
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Location of the flight recording file (\f[CB]\&.jfr\f[R])
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.RS
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.RE
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.SS jfr \f[CB]assemble\f[R] subcommand
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.PP
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Use jfr \f[CB]assemble\f[R] to assemble chunk files into a recording file.
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.PP
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The syntax is:
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.PP
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\f[CB]jfr\ assemble\f[R] <\f[I]repository\f[R]> <\f[I]file\f[R]>
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.PP
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where:
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.TP
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.B <\f[I]repository\f[R]>
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Directory where the repository containing chunk files is located
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.RS
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.RE
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.TP
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.B <\f[I]file\f[R]>
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Location of the flight recording file (\f[CB]\&.jfr\f[R])
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.RS
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.RE
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.PP
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Flight recording information is written in chunks.
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A chunk contains all of the information necessary for parsing.
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A chunk typically contains events useful for troubleshooting.
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If a JVM should crash, these chunks can be recovered and used to create
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a flight recording file using this \f[CB]jfr\ assemble\f[R] command.
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These chunk files are concatenated in chronological order and chunk
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files that are not finished (.part) are excluded.
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.SS \f[CB]jfr\ disassemble\f[R] subcommand
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.PP
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Use \f[CB]jfr\ disassemble\f[R] to decompose a flight recording file into
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its chunk file pieces.
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The syntax is:
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.PP
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\f[CB]jfr\ disassemble\f[R] [\f[CB]\-\-max\-chunks\f[R] <\f[I]chunks\f[R]>]
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[\f[CB]\-\-output\f[R] <\f[I]directory\f[R]>] <\f[I]file\f[R]>
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.PP
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where:
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.TP
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.B \f[CB]\-\-output\f[R] <\f[I]directory\f[R]>
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The location to write the disassembled file, by default the current
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directory
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.RS
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.RE
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.TP
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.B \f[CB]\-\-max\-chunks\f[R] <\f[I]chunks\f[R]>
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Maximum number of chunks per file, by default 5.
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The chunk size varies, but is typically around 15 MB.
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.RS
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.RE
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.TP
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.B \f[CB]\-\-max\-size\f[R] <\f[I]size\f[R]>
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Maximum number of bytes per file.
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.RS
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.RE
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.TP
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.B <\f[I]file\f[R]>
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Location of the flight recording file (\f[CB]\&.jfr\f[R])
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.RS
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.RE
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.PP
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This function can be useful for repairing a broken file by removing the
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faulty chunk.
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It can also be used to reduce the size of a file that is too large to
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transfer.
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The resulting chunk files are named \f[CB]myfile_1.jfr\f[R],
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\f[CB]myfile_2.jfr\f[R], etc.
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If needed, the resulting file names will be padded with zeros to
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preserve chronological order.
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For example, the chunk file name is \f[CB]myfile_001.jfr\f[R] if the
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recording consists of more than 100 chunks.
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.SS jfr version and help subcommands
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.PP
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Use \f[CB]jfr\ \-\-version\f[R] or \f[CB]jfr\ version\f[R] to view the
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version string information for this jfr command.
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.PP
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To get help on any of the jfr subcommands, use:
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.PP
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\f[CB]jfr\ <\-\-help|help>\f[R] [\f[I]subcommand\f[R]]
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.PP
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where:
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.PP
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[\f[I]subcommand\f[R]] is any of:
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.IP \[bu] 2
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\f[CB]print\f[R]
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.IP \[bu] 2
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\f[CB]metadata\f[R]
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.IP \[bu] 2
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\f[CB]summary\f[R]
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.IP \[bu] 2
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\f[CB]assemble\f[R]
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.IP \[bu] 2
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\f[CB]disassemble\f[R]
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