[Bigdata-developers] Analytic Mode and concurrent queries

[Edgar Rodriguez-D. <ed...@sy...>]

Hi,

We’ve been experimenting with analytic mode using a dataset with ~12M
quads.
While running a particular query, a bit complex, it produces the following
running times consistently:

Blazegraph version: 2.0.1

Using Java Heap
Mem Configurations tried: (Xms4g, Xmx8g)

Concurrency Level | Approx avg. execution time
------------------|---------------------------
1                 | 3.5
3                 | 5.0
5                 | 5.5
9                 | 8
10                | 9

Using Analytic Mode
Mem Configurations tried:
(Xms2g, Xmx2g, -XX:MaxDirectMemorySize=6g),
(Xms4g, Xmx4g, -XX:MaxDirectMemorySize=4g)

Concurrency Level | Approx avg. execution time
------------------|---------------------------
1                 | 3.09
3                 | 5.95
5                 | 10.58
9                 | 19.24
10                | 22.87

On levels of concurrency > 3, queries are highly penalized on performance,
being at least
2x slower. I know that there may be an overhead on performance for BG doing
it's own memory management, but
2x slower queries on relatively low levels of concurrency seems like a bit
too high.

So, the questions are:
Is the previous outcome something expected or an exception?, if it's an
exception I could follow up with a bug report.
What can be expected on the performance of concurrent queries while on
analytic mode?