Hehe, goofup on my side. Spoiler alert:Needed swap.

But I think monet could do something smart about it.

Further observations:

Followed Fabian's idea and installed the nightly build@ http://monetdb.cwi.nl/testweb/web/44451:5aebbb6f96b0/MonetDB-11.11.0.tar.bz2

This is a different machine. Same config though.($G RAM, 2.27GHz single core Intel(R) Xeon(R))

This time it topped 65% of the RAM. However the client still failed with the same thing.

Fabian pointed out the possibility of the OOM assassin.

So I checked my box using the "free" command. It had no swap.

Added some 4GB swap file using instructions on https://help.ubuntu.com/community/SwapFaq

sudo dd if=/dev/zero of=/mnt/4096MiB.swap bs=1024 count=4194304

sudo chmod 600 /mnt/4096MiB.swap

sudo mkswap /mnt/4096MiB.swap

sudo swapon /mnt/4096MiB.swap

Add "/mnt/4096MiB.swap none swap sw 0 0" as last line of /etc/fstab

This solved the issue.

Ran 20 queries from single remote machine: RAM usage topped 81% and kept fluctuating 35-70% approx.

Average exec time 195 sec

Ran case 2- 20 queries, 10 from one machine, 10 from another concurrently. Queries were fired at 5 sec intervals.(Case 2 if u see my last post)

Average exec time 348 sec

I guess its the overhead due to lack of main memory. At least its not being killed anymore.

Takes up around 650 MB of swap.

For comparison of the nightly build with earlier box with stable build, ran the 10 queries from single remote box ( with the given data this succeeds even without swap).

New box(nightly build) with swap: 65 sec avg.

Earlier box(Stable build) without swap: 47 sec avg.

Two components in change involved:

1. Environment change(machine, network etc.). Best candidate causing the delay.

2. Algo changes in the nightly build. I am guessing this must be towards better..

Now,

any pointers as to if and how do I optimise when the data bulges into swap.

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Adding swap to earlier machine (stable build) to test the case 2 again - 20 queries - two remote machines firing 10 clients each

179 sec avg.

Thanks and Regards,

Tapomay.