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"control file parallel write" wait event occurs too frequent on BLOB operations

user12024388Dec 30 2021

Hello!
I would like to transfer BLOB data from one table to another in my Oracle APEX application. Oracle Database version is 19.9.0.0.201020.
Here is my code:
1.jpgWhen I try to execute this code it takes too many time to get completed. I have found that some wait events occur when this code is executed.
Here is an information about wait events at moment about three minutes later from code execution start point.
2.jpgAnd here is an information about wait events at moment about ten minutes later from code execution start point.
3.jpgAs you could see there are a lots of "control file parallel write" events occur. And performance is really poor.
The table where I insert BLOB data is defined as:
CREATE TABLE FILES
(
ID_FILE NUMBER NOT NULL,
FILE_NAME VARCHAR2(128 CHAR),
CONTENT BLOB NOT NULL,
MIME_TYPE VARCHAR2(128 CHAR),
FILE_SIZE NUMBER
)
LOB (CONTENT) STORE AS BASICFILE (
TABLESPACE ASIO_NPI_LOB
ENABLE STORAGE IN ROW
CHUNK 32768
PCTVERSION 10
NOCACHE
NOLOGGING
STORAGE (
INITIAL 100M
NEXT 100M
MINEXTENTS 1
MAXEXTENTS UNLIMITED
PCTINCREASE 0
BUFFER_POOL DEFAULT
))
TABLESPACE ASIO_NPI
PCTUSED 0
PCTFREE 10
INITRANS 1
MAXTRANS 255
STORAGE (
INITIAL 64K
NEXT 1M
MINEXTENTS 1
MAXEXTENTS UNLIMITED
PCTINCREASE 0
BUFFER_POOL DEFAULT
)
LOGGING
NOCOMPRESS
NOCACHE
MONITORING;
And tablespace where the LOB segment placed is defined as:
CREATE TABLESPACE ASIO_NPI_LOB DATAFILE '/u02/oradata/CPNDB/asio_npi_lob01.dbf' SIZE 100M AUTOEXTEND ON NEXT 10M MAXSIZE 25G NOLOGGING EXTENT MANAGEMENT LOCAL AUTOALLOCATE SEGMENT SPACE MANAGEMENT AUTO;
So my question is quite simple: how to decrease "control file parallel write" events occur?
Best regards and hope your help.

This post has been answered by Jonathan Lewis on Dec 30 2021
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Comments

843807
I use a program by PDFGo.com to view pdf files right in a jpanel.
Get it at http://www.pdfgo.com
Use the jar file and in about 4 lines of code you can view a PDF file right in your jpanel. They give you the code to pretty much cut and paste into your program. Pretty nifty.
843810
hi

this url is under construction... can you send me this library??? I have to convert a pdf to an image... can you help me??

thanks in advance...
843810
PDY GO is not longer available
I would be very please to obtain a copy of this software for an internal use in my company
Thank's in advance
Regards
843810
the software is still available by registering at www.pdfgo.com
843810
Theres a LGPL version of JPedal that views PDFs in swing pretty easy. http://www.jpedal.org/all_download.php. They've got a bunch of tutorials plus in the source you can see their AppletViewer class, its only a few lines.
PhHein
You're 8 (eight !) years late.

Welcome to the forum. Please don't post in threads that are long dead and don't hijack other threads. When you have a question, start your own topic. Feel free to provide a link to an old post that may be relevant to your problem.

I'm locking this thread now.
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