lob writing performance issue

Discussion of open issues, suggestions and bugs regarding ODAC (Oracle Data Access Components) for Delphi, C++Builder, Lazarus (and FPC)
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a-s-z
Posts: 106
Joined: Wed 03 Dec 2008 06:01

lob writing performance issue

Post by a-s-z » Thu 02 Jul 2009 05:46

Hello,

I want to optimize the performance, when writing lob values to the database. The Odac help says that I should change MemData.DefaultPieceSize, but this is declared as a const :(

Standard transfer rate is around 300-500kb/s in a 100MBit network.
When changing the value to 512k within the debugger, I can improve the performance to more than 2Mb/s, but only in oci mode. Direct mode does not seem to consider DefaultPieceSize, the piece size seems to be fixed around 32k (standard DefaultPieceSize/2?) and performance stays at 300-500k/s:(

Is it possible to improve writing performance in direct mode? Why is DefaultPieceSize ignored in direct mode?
Reading performance seems to be good in both modes.
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Plash
Devart Team
Posts: 2844
Joined: Wed 10 May 2006 07:09

Post by Plash » Wed 15 Jul 2009 09:39

We will change DefaultPieceSize to var in the next ODAC build.

We'll also fix the Direct mode. So DefaultPieceSize will have influence on the LOB performance in this mode.
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