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Different memory utilization

We did 2 similar test installations of Vertica database on virtual RedHat system (the same OS version, RAM and CPU core used, standalone version). Both intances had the same data loaded but we observed strange difference in memory utilization. First instance used average 16-20% of memory (reported by memory_usage table) during normal workload and second one reported always 70%-80% of memory usage (even after database stop and start it goes immediately up to 70% with no workload). The only difference I found was different VMWare version and different hardware configuration, but OS and Vertica files and configuration (especially Vertica parameters) were exactly the same. Is it possible that different hardware or VMWare version can have such impact on memory consumption by HP Vertica? We used version HP Vertica 6.1.2 and RHEL 6.4 64bit.

Comments

  • Hi! >> Is it possible that different hardware or VMWare version can have such impact on memory consumption by HP Vertica? Yes, it's possible. Do you know how VMWare utilize memory? Different VMWare versions can utilize different. Do you see "better utilization" with more modern VMWare version or with an older version?
  • Hi, We found the solution, the difference in WMware configuration was related with balloon driver. Instance with better (lower) memory utilization had this feature turned off. It was enough to turn off "ballooning" in new enviroment and Vertica utilize memory as expected. So you are right, that WMware configuration have important impact on Vertica memory performance, thanks for this clue.
  • Hi! Once I saw a big difference in memory allocation between VMWare and physical host for long char fields (varchar(1024) and bigger). Same request, same data, but on VMWare query used in much more memory. It was in version 8, in version 9 I didn't saw a difference (bug fixed :))). BTW: I tested data type length and my tests shows that Vertica prefers length in power 2, for example its better to define length as 1024 than 980 or 16 than 13 (but for small lengths its almost has no impact). But it require a new test for current Vertica version(may be it changed).

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