Hello, Igniters. > Why test on TC can allocate Data Region bigger than the amount of available > RAM?
Seems, we are using `echo 1 > /proc/sys/vm/overcommit_memory` on TC. So I should fix my test :). В Пн, 15/04/2019 в 13:41 +0300, Nikolay Izhikov пишет: > Hello, Ilya. > > > Ignite does not touch every page of data region, and until you touch a page > > OS will not allocate any specific physical RAM to the virtual RAM address > > of that page. > > This is not true. > Take a look into this discussion [1] > > > Moreover, AFAIK Ignite will not even allocate all the memory permitted by > > data region until it is needed > > May be I miss something, but > > 1. If persistenEnabled = false Ignite will allocate 1 segment on start [2] > 2. If persistenEnabled = true Ignite will allocate all segments on start [3] > > > If you would use Pre-Touch feature which was suggested in this developer > > list a few months ago, you will see it fail explicitly. > > Locally, test already work as expected. > But on TC it fails and DataRegion of 1024GiB can be created. > > Seems, there is some flag on TC that enable this behaviour. > > [1] > http://apache-ignite-developers.2346864.n4.nabble.com/Data-regions-on-client-nodes-td32834.html > [2] > https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/pagemem/impl/PageMemoryNoStoreImpl.java#L245 > [3] > https://github.com/apache/ignite/blob/master/modules/core/src/main/java/org/apache/ignite/internal/processors/cache/persistence/pagemem/PageMemoryImpl.java#L386 > > > В Пн, 15/04/2019 в 10:18 +0300, Ilya Kasnacheev пишет: > > Hello! > > > > Ignite does not touch every page of data region, and until you touch a page > > OS will not allocate any specific physical RAM to the virtual RAM address > > of that page. > > > > Moreover, AFAIK Ignite will not even allocate all the memory permitted by > > data region until it is needed. It will allocate memory in chunks, which > > means your system will slow to grind trying to find RAM for the next chunk > > as you try to load data into such node. > > > > If you would use Pre-Touch feature which was suggested in this developer > > list a few months ago, you will see it fail explicitly. > > > > Regards,
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