[
https://issues.apache.org/jira/browse/PDFBOX-5823?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17847855#comment-17847855
]
Jonathan Prates edited comment on PDFBOX-5823 at 5/20/24 12:44 PM:
-------------------------------------------------------------------
Sure, I mean, contains() is slower for big strings, but not for small ones. My
suggestion is to use a set, in order to avoid memory allocation and resolve in
O ( 1 ) time.
{code:java}
var SPACES = Set.of(" ", "\t", "\n", "\r", "\f", " x0B");{code}
Attached I've provided a simple benchmark: [^Main.java]I can see a similar
pattern on memory allocation for regexp here.
Regarding GC, yes, memory will be cleaned in the next cycle, but since we are
working in a web environment that has concurrent requests and a limited amount
of memory per container, I believe less memory allocation can be beneficial.
was (Author: JIRAUSER305510):
Sure, I mean, contains() is slower for big strings, but not for small ones. My
suggestion is to use a set, in order to avoid memory allocation and resolve in
O ( 1 ) time.
{code:java}
var SPACES_SET = Set.of(" ", "\t", "\n", "\r", "\f", " x0B");{code}
Attached I've provided a simple benchmark: [^Main.java]I can see a similar
pattern on memory allocation for regexp here.
Regarding GC, yes, memory will be cleaned in the next cycle, but since we are
working in a web environment that has concurrent requests and a limited amount
of memory per container, I believe less memory allocation can be beneficial.
> StringUtil.PATTERN_SPACE memory optmisation
> -------------------------------------------
>
> Key: PDFBOX-5823
> URL: https://issues.apache.org/jira/browse/PDFBOX-5823
> Project: PDFBox
> Issue Type: Improvement
> Components: PDModel
> Affects Versions: 3.0.3 PDFBox
> Reporter: Jonathan Prates
> Priority: Minor
> Attachments: Main.java, Screenshot 2024-05-19 at 22.39.10.png,
> Screenshot 2024-05-19 at 22.40.17.png
>
>
> PDAbstractContentStream uses StringUtil.PATTERN_SPACE regexp to evaluate if a
> word has a space in it
> ([https://github.com/apache/pdfbox/blob/trunk/pdfbox/src/main/java/org/apache/pdfbox/pdmodel/PDAbstractContentStream.java#L1624])
> For large documents ~800 pages and small string sequences (like a regular
> word), it causes a memory overhead (see attached), due to the several extra
> allocations. I've replaced the regexp for space and \t using word.contains,
> and since it's a O ( 1 ) operation that does not require extra allocations,
> memory used has been reduced.
> What would be the implications of replacing this block for contains()?
> Since \s is [ \t\n\x0B\f\r], I believe we have a simplified version to
> allocate less memory.
>
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@pdfbox.apache.org
For additional commands, e-mail: dev-h...@pdfbox.apache.org
