# UDF performance

**URL:** <https://discuss.aerospike.com/t/udf-performance/1403>\
**Category:** Tuning\
**Created:** [June 19, 2015, 8:40pm UTC](https://discuss.aerospike.com/t/udf-performance/1403 "2015-06-19T20:40:55Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![jiten](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jiten](https://discuss.aerospike.com/u/jiten)\
**Post date:** [June 19, 2015, 8:40pm UTC](https://discuss.aerospike.com/t/udf-performance/1403/1 "2015-06-19T20:40:55Z")

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Hi,

```
 We're evaluating Aerospike as one of the in-memory NoSQL solutions. The primary goal is to have very low latency and very high ingestion rate. 

Environment
   . Aerospike 3.5.x server installed on a single machine
   . CentOS, 20 cores (in HT mode) , so 40 virtual cores
   . 125Gb memory.
   . This is a dedicated "bare metal" machine for Aerospike.

We ingested 2 million records on this instance (each record has about 7 bins, mostly integer and a couple of string type)
 We're using the count UDF described on your website to get a row count. Executing a query like "aggregate count() on <ns>.<set> takes 1.4 secs as measured using aql. While this query is executing, top shows barely 3/4 cores are used out of 40 with utilization around 45%. The rest are idle. Also, most of the memory on this box is also available for use.

The question is - What is preventing us from getting a millsecond response time for this miniscule data when CPU/memory are obviously not a limiting factors? Do we need to tweak any other configuration parameter? 

These results were captured after executing "afterburner.sh" script.

```

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**Author:** ![ManuelSchmidt](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.aerospike.com/manuelschmidt/32/424_2.png) [@ManuelSchmidt](https://discuss.aerospike.com/u/ManuelSchmidt)\
**Post date:** [June 20, 2015, 9:47am UTC](https://discuss.aerospike.com/t/udf-performance/1403/2 "2015-06-20T09:47:29Z")

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Not sure if the following applies but I remember to have seen a lua instance pool size set to about 5 instances. Not sure if it was client- or serverside configuration. Anyways, if you want only counters I would not use UDFs. I had a similiar usecase where I needed to get a count on something and ended up implementing one in application logic using only AS kvs-functionality (incrementing a counter record on inserts, decrementing on deletes) which provides me with sub-millisecond response no matter what ( o(log(1) ). Aggregation counts will become slower and slower with every new entry ( o(log(n) ) and I think you shouldn’t consider any stream UDF as ‘realtime’ as they may take a few secs or even longer.

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**Author:** ![rbotzer](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.aerospike.com/rbotzer/32/2114_2.png) [@rbotzer](https://discuss.aerospike.com/u/rbotzer)\
**Post date:** [June 20, 2015, 2:24pm UTC](https://discuss.aerospike.com/t/udf-performance/1403/3 "2015-06-20T14:24:17Z")

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Unrelated to UDFs, make sure your transaction-queues and service-threads are configured to the number of cores as described in the [configuration reference](http://www.aerospike.com/docs/reference/configuration/).

As Manuel described, UDFs are added functionality to the key-value operations, using Lua scripts. The server includes LuaJIT which should provide better performance for repeated calls, but still not at the same order of speed as the core key-value operations. If you try to run the same command through AQL several times in a row does the execution time improve?

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**Author:** ![jiten](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jiten](https://discuss.aerospike.com/u/jiten)\
**Post date:** [June 20, 2015, 6:50pm UTC](https://discuss.aerospike.com/t/udf-performance/1403/4 "2015-06-20T18:50:45Z")

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Running the same command multiple times in AQL doesn’t help. We’ll configure transaction-queues and service-threads as suggested and keep you posted.

Thanks for your suggestion and comments.

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**Author:** ![jiten](https://avatars.discourse-cdn.com/v4/letter/j/e9c0ed/32.png) [@jiten](https://discuss.aerospike.com/u/jiten)\
**Post date:** [June 22, 2015, 8:54pm UTC](https://discuss.aerospike.com/t/udf-performance/1403/5 "2015-06-22T20:54:14Z")

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Hi,

The transaction-queues and service-threads parameters were already configured to the number of cores. It still uses only 4 cores for some reason.

Thanks