<html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:w="urn:schemas-microsoft-com:office:word" xmlns:m="http://schemas.microsoft.com/office/2004/12/omml" xmlns="http://www.w3.org/TR/REC-html40">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Generator" content="Microsoft Word 15 (filtered medium)">
<style><!--
/* Font Definitions */
@font-face
        {font-family:"Cambria Math";
        panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
        {font-family:Calibri;
        panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
        {font-family:"Segoe UI";
        panose-1:2 11 5 2 4 2 4 2 2 3;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
        {margin:0cm;
        margin-bottom:.0001pt;
        font-size:12.0pt;
        font-family:"Times New Roman",serif;}
a:link, span.MsoHyperlink
        {mso-style-priority:99;
        color:blue;
        text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
        {mso-style-priority:99;
        color:purple;
        text-decoration:underline;}
p
        {mso-style-priority:99;
        mso-margin-top-alt:auto;
        margin-right:0cm;
        mso-margin-bottom-alt:auto;
        margin-left:0cm;
        font-size:12.0pt;
        font-family:"Times New Roman",serif;}
p.msonormal0, li.msonormal0, div.msonormal0
        {mso-style-name:msonormal;
        mso-margin-top-alt:auto;
        margin-right:0cm;
        mso-margin-bottom-alt:auto;
        margin-left:0cm;
        font-size:12.0pt;
        font-family:"Times New Roman",serif;}
span.EmailStyle18
        {mso-style-type:personal-reply;
        font-family:"Calibri",sans-serif;
        color:#1F497D;}
.MsoChpDefault
        {mso-style-type:export-only;
        font-family:"Calibri",sans-serif;
        mso-fareast-language:EN-US;}
@page WordSection1
        {size:612.0pt 792.0pt;
        margin:72.0pt 72.0pt 72.0pt 72.0pt;}
div.WordSection1
        {page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
</head>
<body lang="EN-GB" link="blue" vlink="purple">
<div class="WordSection1">
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">(I put this in the PR, but maybe drafts don’t get updates put on the mailing list?)<o:p></o:p></span></p>
<p style="margin-bottom:12.0pt;background:white"><span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">HeapDumpOverwrite sounds quite general, there are different ways of heap dumping and this doesn't affect all of them. This could
 be HeapDumpOnOutOfMemoryErrorOverwrite, which is a long option even for us 8-) so could be abbreviated perhaps, BUT that option might not be the way to do it…<o:p></o:p></span></p>
<p style="margin-bottom:12.0pt;background:white;box-sizing: border-box;font-variant-ligatures: normal;font-variant-caps: normal;orphans: 2;text-align:start;widows: 2;-webkit-text-stroke-width: 0px;text-decoration-thickness: initial;text-decoration-style: initial;text-decoration-color: initial;word-spacing:0px">
<span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">Is it really that all heap dumps should be permitted to an existing file, IF that file is a FIFO? From the email I think that's the problem? ..and if so, we have:<o:p></o:p></span></p>
<p style="mso-margin-top-alt:0cm;margin-right:0cm;margin-bottom:12.0pt;margin-left:0cm;background:white;box-sizing: border-box;font-variant-ligatures: normal;font-variant-caps: normal;orphans: 2;text-align:start;widows: 2;-webkit-text-stroke-width: 0px;text-decoration-thickness: initial;text-decoration-style: initial;text-decoration-color: initial;word-spacing:0px">
<span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">8267666: Add option to jcmd GC.heap_dump to use existing file<br>
<a href="https://bugs.openjdk.org/browse/JDK-8267666"><span style="text-decoration:none">https://bugs.openjdk.org/browse/JDK-8267666</span></a><o:p></o:p></span></p>
<p style="margin-top:0cm;background:white;box-sizing: border-box;font-variant-ligatures: normal;font-variant-caps: normal;orphans: 2;text-align:start;widows: 2;-webkit-text-stroke-width: 0px;text-decoration-thickness: initial;text-decoration-style: initial;text-decoration-color: initial;word-spacing:0px">
<span style="font-size:10.5pt;font-family:"Segoe UI",sans-serif;color:#1F2328">So if jcmd to create a dump can use an existing file, -XX:OnError= can trigger such a jcmd? 
<br>
<br>
i.e. Maybe there is a way of doing what you want.  A code change could still be required to make this easier for heap dumps on out of memory.  Writing a JBS bug first is useful to define the problem.<br>
<br>
Thanks<br>
Kevin<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> jdk-dev <jdk-dev-retn@openjdk.org>
<b>On Behalf Of </b>Elon Azoulay<br>
<b>Sent:</b> 25 May 2023 21:21<br>
<b>To:</b> Daniel Daugherty <daniel.daugherty@oracle.com><br>
<b>Cc:</b> serviceability-dev@openjdk.org; jdk-dev@openjdk.org<br>
<b>Subject:</b> Re: [External] : Re: Proposal: Add overwrite heapdump flag to java<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<p class="MsoNormal">Sounds good, thanks so much!<o:p></o:p></p>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">On Thu, May 25, 2023 at 12:13 PM <<a href="mailto:daniel.daugherty@oracle.com">daniel.daugherty@oracle.com</a>> wrote:<o:p></o:p></p>
</div>
<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm">
<div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:"Courier New"">Pointing the older thread to this newer incarnation would be a good idea.<br>
<br>
Dan<br>
<br>
</span><o:p></o:p></p>
<div>
<p class="MsoNormal">On 5/25/23 3:11 PM, Elon Azoulay wrote:<o:p></o:p></p>
</div>
<blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
<div>
<p class="MsoNormal">Hi Dan, <o:p></o:p></p>
<div>
<p class="MsoNormal">That's great! Should I follow up in that thread as well?<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</div>
<p class="MsoNormal"><o:p> </o:p></p>
<div>
<div>
<p class="MsoNormal">On Thu, May 25, 2023 at 12:04 PM <<a href="mailto:daniel.daugherty@oracle.com" target="_blank">daniel.daugherty@oracle.com</a>> wrote:<o:p></o:p></p>
</div>
<blockquote style="border:none;border-left:solid #CCCCCC 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm">
<p class="MsoNormal" style="margin-bottom:12.0pt">Greetings,<br>
<br>
A similar request came up on the hotspot-dev alias back in 2022.11:<br>
<br>
<a href="https://mail.openjdk.org/pipermail/hotspot-dev/2022-November/066956.html" target="_blank">https://mail.openjdk.org/pipermail/hotspot-dev/2022-November/066956.html</a><br>
<br>
Dan<br>
<br>
<br>
On 5/25/23 1:48 AM, David Holmes wrote:<br>
> Hi Elon,<br>
><br>
> I would suggest taking this up on serviceability-dev - cc'd.<br>
><br>
> On 25/05/2023 3:46 am, Elon Azoulay wrote:<br>
>> Hi,<br>
>> I submitted a pull request <br>
>> <<a href="https://urldefense.com/v3/__https:/github.com/openjdk/jdk/pull/13276__;!!ACWV5N9M2RV99hQ!P4XNOUSVFXTWEIX8H89o1hhVY4MkuYC-SezupmhJPMkq4ytSpJqLz-jQjNkp906DjKBK_EuRIoL1MtBM2AGEbVqkI0M$" target="_blank">https://github.com/openjdk/jdk/pull/13276</a>>
 to expose the overwrite <br>
>> flag to HeapDumpOnOutOfMemoryError.<br>
>> The flag is already exposed to jcmd as -overwrite.This is to <br>
>> facilitate creating a heapdump within a container native environment.<br>
>> We use this internally to dump the heap dump to a fifo so that we <br>
>> could read it in a separate container.Let me know what needs to be <br>
>> done in terms of creating an issue and getting my pr merged.<br>
><br>
> Have you gone through the guide:<br>
><br>
> <a href="https://openjdk.org/guide/" target="_blank">https://openjdk.org/guide/</a><br>
><br>
> ?<br>
><br>
> You will need a JBS issue and also a CSR request as this proposes to <br>
> add a new manageable product flag.<br>
><br>
> Cheers,<br>
> David<br>
><br>
>> I am a new contributor and would be happy to contribute more!<br>
>><br>
>> Cheers,<br>
>><br>
>> Elon<o:p></o:p></p>
</blockquote>
</div>
</blockquote>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
</blockquote>
</div>
</div>
</body>
</html>