Using QuickPDF DLL in multiple threads

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   Hi,

At the moment I open the same PDF using DAFileOpenReadOnly in 4 separate processes and in each one process different pages from this PDF.

I am trying to switch to using a single process, and to use 4 threads instead. I access the DLL in each thread separately (as the docs say) but performance is dismal compared to the separate processes approach. 

Is there any kind of 'global mutex' or similar that could be a choke point for a multithreaded approach?

Thanks.

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quickpdfdeveloper Members Profile Find Members Posts Team Player Joined: 19 Mar 17 Status: Offline Points: 32	Post Options Post Reply Quote quickpdfdeveloper Report Post Thanks(0) Quote Reply Topic: Using QuickPDF DLL in multiple threads Posted: 25 Feb 18 at 8:39PM
	Hi, At the moment I open the same PDF using DAFileOpenReadOnly in 4 separate processes and in each one process different pages from this PDF. I am trying to switch to using a single process, and to use 4 threads instead. I access the DLL in each thread separately (as the docs say) but performance is dismal compared to the separate processes approach. Is there any kind of 'global mutex' or similar that could be a choke point for a multithreaded approach? Thanks.

kevindebenu Members Profile Find Members Posts Moderator Group Joined: 16 Apr 12 Status: Offline Points: 7	Post Options Post Reply Quote kevindebenu Report Post Thanks(0) Quote Reply Posted: 20 Mar 18 at 9:58AM
	Hello quickpdfdeveloper, A global mutex is used in each function in QPL to access the internal list of QPL instances, but this is only for accessing the instance. Once the instance has been retrieved from the list there isn't a lock on the actual internal function call. The slow performance could be caused by the particular functions you're using. Once you've called DAFileOpenReadOnly, what other QPL functions are you using? Regards, Kevin

quickpdfdeveloper Members Profile Find Members Posts Team Player Joined: 19 Mar 17 Status: Offline Points: 32	Post Options Post Reply Quote quickpdfdeveloper Report Post Thanks(0) Quote Reply Posted: 23 Mar 18 at 3:35PM
	I use the following functions (here shown in alphabetical order) after unlocking DPL: da_close_file da_extract_page_text da_extract_page_text_blocks da_find_page da_get_page_count da_get_page_height da_get_text_block_bound da_get_text_block_char_width da_get_text_block_count da_get_text_block_text da_normalize_page da_open_file_read_only da_release_text_blocks da_set_text_extraction_word_gap last_error_code Thanks.