lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Shawn Heisey (JIRA)" <>
Subject [jira] [Commented] (SOLR-13446) Improve default heap size and related handling
Date Fri, 03 May 2019 23:37:00 GMT


Shawn Heisey commented on SOLR-13446:

{quote}Just let the JVM do it's thing?
I'm ambivalent about this idea.

On the negative side, I think that doing this would contribute to the general misconception
people have that "Java is a memory hog." Although I do not agree with that perception, I'm
not going to try and disprove it here.

On the plus side, there's near zero chance that the heap will be too large.  It could end
up being too small!

Incorporating your idea, here's a more fleshed out proposal:
 * If explicit memory options are such that the max heap is above the threshold, or the admin
has configured the option to disable logging, then nothing will be logged. We could consider
trying to detect when the heap size is way too big for the available memory in the server,
but I'm not sure we need to do that.
 * If no memory options are given, and/or the max heap size is below a certain threshold,
we log one or two warnings, with text like the following:
 ** "The heap size was not restricted at startup. Java has chosen a max heap size of XXXX.
If this is not acceptable, please configure Solr to use a specific heap size. See [https://blahblah|https://blahblah/]
for details."
 ** "Solr is running with a heap size of XXXX. This is a small heap, which might cause operational
or performance problems. See [https://blahblah|https://blahblah/] for details."


> Improve default heap size and related handling
> ----------------------------------------------
>                 Key: SOLR-13446
>                 URL:
>             Project: Solr
>          Issue Type: Improvement
>      Security Level: Public(Default Security Level. Issues are Public) 
>          Components: scripts and tools
>    Affects Versions: 8.0
>            Reporter: Shawn Heisey
>            Priority: Minor
> Solr's scripts have a default max heap setting of 512MB.  I think it's fair to say that
for a production install, this is ridiculously small.  Nearly everyone who runs a Solr server
will need to increase this value.
> I think it would be useful to issue a warning in the log when the heap size is below
a certain value.  Text like "Detected max heap size is XXXX.  It might be necessary to increase
the heap size for proper operation.  See
for details."
> For people who are running very small servers, there should be a config option to turn
off that logging when somebody knows that the default heap size is perfectly fine for their
> At the same time, we also need to improve the default heap size.  I'm going to ask everyone
to bikeshed about what the new default should be.  Initial thought is a 2GB default, to be
made smaller automatically if detected system memory is low.  If the admin has explicitly
set the heap size, then none of this will take place.

This message was sent by Atlassian JIRA

To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message