I have a django application that does some heavy computation. It works very good with less data on my machine and on 'aws -elasticbeanstalk' as well. But When the data becomes large it on aws, gives, internal server error, and in the logs it shows:
[core:error]End of script output before headers: wsgi.py
However works fine on my machine
The code where it constantly gives this error is :
[my_big_lst[int(i[0][1])-1].appendleft((int(i[0][0]) - i[1])) for i in itertools.product(zipped_list,temp_list)]
where:
my_big_lst is a big list of deques
zipped_list is a large list of tuples
temp_list is a large list of numbers
It is notable, that as data grows large, the processing time also increases, and also that this problem is only coming on aws when data is large, and on my machine, it always works fine.
Update:
I worked out, that this error happens when the processing time exceeds 60 seconds, I also changed the Idle Loadbalancer time to 3600, but no effect, still error is there
Please anyone suggest a solution ?
If you are using a c-extension module, You could try setting
WSGIApplicationGroup %{GLOBAL}
in your virtualhost.
Something about python subinterpreters not working with c-extension modules. However since your code works for a smaller data set, your problem might be solved by setting memory-specific directives.
https://code.google.com/archive/p/modwsgi/wikis/ApplicationIssues.wiki#Python_Simplified_GIL_State_API
Related
I am following the tutorial on
Center for High Throughput Computing and Introduction to Configuration in the HTCondor website to set up a Partitionable slot. Before any configuration I run
condor_status
and get the following output.
I update the file 00-minicondor in /etc/condor/config.d by adding the following lines at the end of the file.
NUM_SLOTS = 1
NUM_SLOTS_TYPE_1 = 1
SLOT_TYPE_1 = cpus=4
SLOT_TYPE_1_PARTITIONABLE = TRUE
and reconfigure
sudo condor_reconfig
Now with
condor_status
I get this output as expected. Now, I run the following command to check everything is fine
condor_status -af Name Slotype Cpus
and find slot1#ip-172-31-54-214.ec2.internal undefined 1 instead of slot1#ip-172-31-54-214.ec2.internal Partitionable 4 61295 that is what I would expect. Moreover, when I try to summit a job that asks for more than 1 cpu it does not allocate space for it (It stays waiting forever) as it should.
I don't know if I made some mistake during the installation process or what could be happening. I would really appreciate any help!
EXTRA INFO: If it can be of any help have have installed HTCondor with the command
curl -fsSL https://get.htcondor.org | sudo /bin/bash -s – –no-dry-run
on Ubuntu 18.04 running on an old p2.xlarge instance (it has 4 cores).
UPDATE: After rebooting the whole thing it seems to be working. I can now send jobs with different CPUs requests and it will start them properly.
The only issue I would say persists is that Memory allocation is not showing properly, for example:
But in reality it is allocating enough memory for the job (in this case around 12 GB).
If I run again
condor_status -af Name Slotype Cpus
I still get something I am not supposed to
But at least it is showing the correct number of CPUs (even if it just says undefined).
What is the output of condor_q -better when the job is idle?
I got an ER_NET_PACKETS_OUT_OF_ORDER error when running a multithreaded C++ app using Poco::Data::MySQL and Poco::Data::SessionPool. The error message looks like this:
MySQL: [MySQL]: [Comment]: mysql_stmt_prepare error [mysql_stmt_error]: Got packets out of order [mysql_stmt_errno]: 1156 [mysql_stmt_sqlstate]: 08S01 [statemnt]: ...
The app is making queries from multiple threads every 100ms. The connections are provided by a common SessionPool.
I got around this problem by adding reset=true to the connection string. However, as stated in the official docs, adding this option may result in problems with encoding.
I am building a website with NextJS that takes some time to build. It has to create a big dictionary, so when I run next dev it takes around 2 minutes to build.
The issue is, when I run next export to get a static version of the website there is a timeout problem, because the build takes (as I said before), 2 minutes, whihc exceeds the 60 seconds limit pre-configured in next.
In the NEXT documentation: https://nextjs.org/docs/messages/static-page-generation-timeout it explains that you can increase the timeout limit, whose default is 60 seconds: "Increase the timeout by changing the staticPageGenerationTimeout configuration option (default 60 in seconds)."
However it does not specify WHERE you can set that configuration option. In next.config.json? in package.json?
I could not find this information anywhere, and my blind tries of putting this parameter in some of the files mentioned before did not work out at all. So, Does anybody know how to set the timeout of next export? Thank you in advance.
They were a bit more clear in the basic-features/data-fetching part of the docs that it should be placed in the next.config.js
I added this to mine and it worked (got rid of the Error: Collecting page data for /path/[pk] is still timing out after 2 attempts. See more info here https://nextjs.org/docs/messages/page-data-collection-timeout build error):
// next.config.js
module.exports = {
// time in seconds of no pages generating during static
// generation before timing out
staticPageGenerationTimeout: 1000,
}
I am running an Aerospike cluster in Google Cloud. Following the recommendation on this post, I updated to the last version (3.11.1.1) and re-created all servers. In fact, this change cause my 5 servers to operate in a much lower CPU load (it was around 75% load before, now it is on 20%, as show in the graph bellow:
Because of this low load, I decided to reduce the cluster size to 4 servers. When I did this, my application started to receive the following error:
All batch queues are full
I found this discussion about the topic, recommending to change the parameters batch-index-threads and batch-max-unused-buffers with the command
asadm -e "asinfo -v 'set-config:context=service;batch-index-threads=NEW_VALUE'"
I tried many combinations of values (batch-index-threads with 2,4,8,16) and none of them solved the problem, and also changing the batch-index-threads param. Nothing solves my problem. I keep receiving the All batch queues are full error.
Here is my aerospace.conf relevant information:
service {
user root
group root
paxos-single-replica-limit 1 # Number of nodes where the replica count is automatically reduced to 1.
paxos-recovery-policy auto-reset-master
pidfile /var/run/aerospike/asd.pid
service-threads 32
transaction-queues 32
transaction-threads-per-queue 4
batch-index-threads 40
proto-fd-max 15000
batch-max-requests 30000
replication-fire-and-forget true
}
I use 300GB SSD disks on these servers.
A quick note which may or may not pertain to you:
A common mistake we have seen in the past is that developers decide to use 'batch get' as a general purpose 'get' for single and multiple record requests. The single record get will perform better for single record requests.
It's possible that you are being constrained by the network between the clients and servers. Reducing from 5 to 4 nodes reduced the aggregate pipe. In addition, removing a node will start cluster migrations which adds additional network load.
I would look at the batch-max-buffer-per-queue config parameter.
Maximum number of 128KB response buffers allowed in each batch index
queue. If all batch index queues are full, new batch requests are
rejected.
In conjunction with raising this value from the default of 255 you will want to also raise the batch-max-unused-buffers to batch-index-threads x batch-max-buffer-per-queue + 1 (at least). If you do not do that new buffers will be created and destroyed constantly, as the amount of free (unused) buffers is smaller than the ones you're using. The moment the batch response is served the system will strive to trim the buffers down to the max unused number. You will see this reflected in the batch_index_created_buffers metric constantly rising.
Be aware that you need to have enough DRAM for this. For example if you raise the batch-max-buffer-per-queue to 320 you will consume
40 (`batch-index-threads`) x 320 (`batch-max-buffer-per-queue`) x 128K = 1600MB
For the sake of performance the batch-max-unused-buffers should be set to 13000 which will have a max memory consumption of 1625MB (1.59GB) per-node.
Referring to the docs, you can specify the number of concurrent connection when pushing large files to Amazon Web Services s3 using the multipart uploader. While it does say the concurrency defaults to 5, it does not specify a maximum, or whether or not the size of each chunk is derived from the total filesize / concurrency.
I trolled the source code and the comment is pretty much the same as the docs:
Set the concurrency level to use when uploading parts. This affects
how many parts are uploaded in parallel. You must use a local file as
your data source when using a concurrency greater than 1
So my functional build looks like this (the vars are defined by the way, this is just condensed for example):
use Aws\Common\Exception\MultipartUploadException;
use Aws\S3\Model\MultipartUpload\UploadBuilder;
$uploader = UploadBuilder::newInstance()
->setClient($client)
->setSource($file)
->setBucket($bucket)
->setKey($file)
->setConcurrency(30)
->setOption('CacheControl', 'max-age=3600')
->build();
Works great except a 200mb file takes 9 minutes to upload... with 30 concurrent connections? Seems suspicious to me, so I upped concurrency to 100 and the upload time was 8.5 minutes. Such a small difference could just be connection and not code.
So my question is whether or not there's a concurrency maximum, what it is, and if you can specify the size of the chunks or if chunk size is automatically calculated. My goal is to try to get a 500mb file to transfer to AWS s3 within 5 minutes, however I have to optimize that if possible.
Looking through the source code, it looks like 10,000 is the maximum concurrent connections. There is no automatic calculations of chunk sizes based on concurrent connections but you could set those yourself if needed for whatever reason.
I set the chunk size to 10 megs, 20 concurrent connections and it seems to work fine. On a real server I got a 100 meg file to transfer in 23 seconds. Much better than the 3 1/2 to 4 minute it was getting in the dev environments. Interesting, but thems the stats, should anyone else come across this same issue.
This is what my builder ended up being:
$uploader = UploadBuilder::newInstance()
->setClient($client)
->setSource($file)
->setBucket($bicket)
->setKey($file)
->setConcurrency(20)
->setMinPartSize(10485760)
->setOption('CacheControl', 'max-age=3600')
->build();
I may need to up that max cache but as of yet this works acceptably. The key was moving the processor code to the server and not relying on the weakness of my dev environments, no matter how powerful the machine is or high class the internet connection is.
We can abort the process during upload and can halt all the operations and abort the upload at any instance. We can set Concurrency and minimum part size.
$uploader = UploadBuilder::newInstance()
->setClient($client)
->setSource('/path/to/large/file.mov')
->setBucket('mybucket')
->setKey('my-object-key')
->setConcurrency(3)
->setMinPartSize(10485760)
->setOption('CacheControl', 'max-age=3600')
->build();
try {
$uploader->upload();
echo "Upload complete.\n";
} catch (MultipartUploadException $e) {
$uploader->abort();
echo "Upload failed.\n";
}