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I didn't see any properties for limiting the size of memory used by voltdb,when I config voltdb, so I want to ask: Can I config the max size of memory used by voltdb? If I can, how to config?Where is the configuration file? Can voltdb work in mixed mode of memory and disk?

Xu Zhenxue
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1 Answers1

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You can set VoltDB to pause when a certain memory limit is reached. You do this in the configuration file that you start VoltDB with, specifically within the resource monitor section. It would look something like this:

<systemsettings>
  <resourcemonitor frequency="30">
    <memorylimit size="70%" alert="60%"/>
  </resourcemonitor>
</systemsettings>

You can read more about it in the VoltDB documentation: https://docs.voltdb.com/AdminGuide/MonitorSysResource.php

As for your other question, VoltDB doesn't work in a mixed mode of memory and disk. In fact, it is highly recommended that swapping be disabled. You should review the memory management optimizations listed here: https://docs.voltdb.com/AdminGuide/adminmemmgt.php

Full disclosure: I work at VoltDB.

Andrew
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  • Does Voltdb has elimination strategies like LRU for deleting some data or swapping to disk when memory usage reach memory limit? – Xu Zhenxue Aug 22 '19 at 02:05
  • What you want could be achieved by exporting your data to an external server with VoltDB's export feature. We also have a Time To Live (TTL) feature for SQL tables. As of V9.1, you can also configure TTL to export to an external server before deletion. You can read more about TTL here: https://docs.voltdb.com/UsingVoltDB/ddlref_createtable.php – Andrew Aug 22 '19 at 14:36
  • I already know TTL feature. Our team want to use a in-memory ralation database as a cache for data analysis, which can automatically eliminates data that has not been used recently . Does voltdb has this feature? – Xu Zhenxue Aug 24 '19 at 07:20