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https://issues.apache.org/jira/browse/PDFBOX-1337?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13292870#comment-13292870
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Alexis commented on PDFBOX-1337:
--------------------------------

I added a dump with 32 threads BLOCKED et 3 threads RUNNABLE on 
"PDFOperator.java:68"
I'll do a test with 1.7.0
                
> Improve PDFOperator performance on multithreading environment
> -------------------------------------------------------------
>
>                 Key: PDFBOX-1337
>                 URL: https://issues.apache.org/jira/browse/PDFBOX-1337
>             Project: PDFBox
>          Issue Type: Bug
>          Components: Parsing, Utilities
>    Affects Versions: 1.6.0
>            Reporter: Alexis
>         Attachments: thread_dump_pdfbox_1.6.0_PDFOperator_BLOCKED.txt
>
>   Original Estimate: 1h
>  Remaining Estimate: 1h
>
> With more than 6 threads, the API PDFOperator#getOperator(String operator) is 
> still blocked :
> Sample with 48 threads :
> pool-1-thread-46" - Thread t@72
>    java.lang.Thread.State: RUNNABLE
>       at org.apache.pdfbox.util.PDFOperator.getOperator(PDFOperator.java:76)
>       at 
> org.apache.pdfbox.pdfparser.PDFStreamParser.parseNextToken(PDFStreamParser.java:441)
>       at 
> org.apache.pdfbox.pdfparser.PDFStreamParser.access$000(PDFStreamParser.java:46)
>       at 
> org.apache.pdfbox.pdfparser.PDFStreamParser$1.tryNext(PDFStreamParser.java:175)
>       at 
> org.apache.pdfbox.pdfparser.PDFStreamParser$1.hasNext(PDFStreamParser.java:187)
>       at 
> org.apache.pdfbox.util.PDFStreamEngine.processSubStream(PDFStreamEngine.java:266)
> I propose to remove the synchronization of the attribute "operators" and set 
> up a synchronization 
> on the put operation. (This optimization saves 30 percent of time)
> public class PDFOperator
> {
>     [...]
>     // private static Map operators = Collections.synchronizedMap( new 
> HashMap() );
>     private static Map operators = new HashMap();
>     [...]
>     public static PDFOperator getOperator( String operator )
>     {
>         PDFOperator operation = null;
>         if( operator.equals( "ID" ) || operator.equals( "BI" ) )
>         {
>             //we can't cache the ID operators.
>             operation = new PDFOperator( operator );
>         }
>         else
>         {
>             operation = (PDFOperator)operators.get(operator);
>             if( operation == null )
>             {
>               synchronized (operators) {
>                 operation = (PDFOperator)operators.get(operator);
>                 if ( operation == null ) {
>                   operation = new PDFOperator( operator );
>                   operators.put( operator, operation );
>                 }
>               }
>             }
>         }
>         return operation;
>     }
>     [...]
> }

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