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Difference between checkpoint_interval_in_mins and page_flush_interval_in_msecs?

CUBRID Official Forum » General Discussions » Difference between checkpoint_interval_in_mins and page_flush_interval_in_msecs?

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[Level:0]majidazimi

Post subject: Difference between checkpoint_interval_in_mins and page_flush_interval_in_msecs?

registered: 03/09/2013

IP: *.42.54.159

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Hi guys,

I'm confused about difference between checkpoint_interval_in_mins and page_flush_interval_in_msecs? They are both writing dirty pages in buffers to data volume at specific interval. 

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[Level:3]Esen Sagynov

# Post subject:Re: Difference between checkpoint_interval_in_mins and page_flush_interval_in_msecs?

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registered: 05/31/2011

IP: *.91.139.82

Hello Majid Azimi,

Thank you for such a nice question! It's indeed good!

First, you are right about the fact that both flush dirty pages form buffer to a disk (data volume). The difference is thatpage_flush_interval_in_msecs exists for backward compatibility only. This parameter was actionable in earlier versions of CUBRID. However, in the newer version of CUBRID (8.4+), despite a user sets this value, the database engine will ignore it and will use only checkpoint_interval_in_mins or checkpoint_ever_npages parameters to control when the dirty pages must be flushed to the disk. Depending on which of the checkpoint parameters comes first in the current checkpoint cycle, the engine will trigger the checkpoint operation.

So, at this moment, you can focus on checkpoint parameters as they include the functionality of the page flush parameter.

One more thing that I need to tell you is that in the future versions of CUBRID we may remove the checkpoint parameters alltogether as well. In fact, no other relational database allows to configure when and how the engine flushes the data to the disk. This is derived from the idea that the engine must decide based on the current load and disk activity. Allowing users to configure these parameters creates a risk of misconfigurations.

Though these are just plans at this moment, the checkpoint parameters will stay effective for quite some time.

Please let me know if you have other questions.

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