Replicate & Update SQL Server DB to AWS - sql

We need to sync a client's on-premise SQL Server DB to AWS and keep it updated on a scheduled basis.
By client's request I feel forced to ask the following:
Is there any way to do this without RDS, DMS &/or EC2?
I believe this could be achieved in a somewhat unorthodox way through AWS Lambda, but since the original SQL Server DB contains a few +50gb tables I think the Lambda function would constantly run out of memory.
I've looked everywhere and haven't found an answer yet.
Thanks!

That's certainly possible with Lambda but it presents some challenges. You would have to split the jobs into tasks that would fit within the limits of the Lambda runtime, which at this time include 15 minutes max execution time, 3,008 MB RAM, and 512 MB disk space. If the CSVs are too large to fit within those limits, and you want the entire CSV to be processed in a single database transaction, then it may not be possible to implement using Lambda.
I would suggest having a process that pushes the CSVs to S3 which can then trigger Lambda functions directly, or add the file ingest tasks to an SQS queue or Kinesis stream to then be processed by Lambda functions.

Related

Cloud Pub/Sub to BigQuery through Dataflow SQL

I Would like to understand the working of Dataflow pipeline.
In my case, I have something published to cloud pub/sub periodically which Dataflow then writes to BigQuery. The volume of messages that come through are in the thousands so my publisher client has a batch setting for 1000 messages, 1 MB and 10 sec of latency.
The question is: When published in a batch as stated above, Does Dataflow SQL take in the messages in the batch and writes it to BigQuery all in one go? or, Does it writes one message at a time?
On the other hand, Is there any benefit of one over the other?
Please comment if any other details required. Thanks
Dataflow SQL is just a way to define, with SQL syntax, an Apache Beam pipeline, and to run it on Dataflow.
Because it's PubSub, it's a streaming pipeline that is created based on your SQL definition. When you run your SQL command, a Dataflow job starts and wait the messages from pubSub.
If you publish a bunch of messages, Dataflow is able to scale up to process them as soon as possible.
Keep in ming that Dataflow streaming never scale to 0 and therefore you will always pay for 1 or more VM to keep your pipeline up and running.

SQS and AWS Lambda Integration

I am developing an Audit Trail System, that will act as a central location for all the critical events happening around the organization. I am planning to use Amazon SQS as a temporary queue to hold the messages that in turn will trigger the AWS lambda function to write the messages into AWS S3 store. I want to segregate the data at tenantId level (some identifiable id) and persist the messages as batches in S3, that will reduce the no of calls from lambda to S3. Moreover, I want to trigger the lambda every hour. But, I have 2 issues here, one the max batch size provided by SQS is 10, also the lambda trigger polls the SQS service on regular basis, that's gonna increase the no of calls to my S3. I want to create a manual batch of 1000 messages(say) before calling the S3 batch api. I am not very much sure how to architecture my system, so that above requirements can be met. Help or idea provided is very much appreciable!
Simplified Architecture:
Thanks!
I would recommend that you instead use Amazon Kinesis Data Firehose. It basically does what you're wanting to do:
Accepts incoming messages
Buffers them for a period of time
Writes output to S3 or Elasticsearch
This is all done as a managed service, and can also integrate with AWS Lambda to provide custom processing (eg filter out certain records).
However, you might have to do something special to segregate the data at tenantId. See: Can I customize partitioning in Kinesis Firehose before delivering to S3?

Different ways of updating bigquery table

In gcp, I need to update a bigquery table whenever a file (multiple formats such as json,xml) gets uploaded into a bucket. I have two options but not sure what are the pros/cons of each of them. Can someone suggest which is a better solution and why?
Approach 1 :
File uploaded to bucket --> Trigger Cloud Function (which updates the bigquery table) -->Bigquery
Approach 2:
File uploaded to bucket --> Trigger Cloud Function (which triggers a dataflow job) -->Dataflow-->Bigquery.
In production env, which approach is better suited and why? If there are alternative approaches,pls let me know.
This is quite a broad question, so I wouldn't be surprised if it gets voted to be closed. That said however, I'd always go #2 (GCS -> CF -> Dataflow -> BigQuery).
Remember, with Cloud Funtions there is a max execution time. If you kick off a load job from the Cloud Function, you'll need to bake logic into it to poll and check the status (load jobs in BigQuery are async). If it fails, you'll need to handle it. But, what if it's still running and you hit the max execution of your Cloud Function?
At least by using Dataflow, you don't have the problem of max execution times and you can simply rerun your pipeline if it fails for some transient reason e.g. network issues.

Concatenate files in S3 using AWS Lambda

Is there a way to use Lambda for S3 file concatenation?
I have Firehose streaming data into S3 with the longest possible interval (15 minutes or 128mb) and therefore I have 96 data files daily, but I want to aggregate all the data to a single daily data file for the fastest performance when reading the data later in Spark (EMR).
I created a solution where Lambda function gets invoked when Firehose streams a new file into S3. Then the function reads (s3.GetObject) the new file from source bucket and the concatenated daily data file (if it already exists with previous daily data, otherwise creates a new one) from the destination bucket, decode both response bodies to string and then just add them together and write to the destination bucket with s3.PutObject (which overwrites the previous aggregated file).
The problem is that when the aggregated file reaches 150+ MB, the Lambda function reaches its ~1500mb memory limit when reading the two files and then fails.
Currently I have a minimal amount of data, with a few hundred MB-s per day, but this amount will be growing exponentially in the future. It is weird for me that Lambda has such low limits and that they are already reached with so small files.
Or what are the alternatives of concatenating S3 data, ideally invoked by S3 object created event or somehow a scheduled job, for example scheduled daily?
I would reconsider whether you actually want to do this:
The S3 costs will go up.
The pipeline complexity will go up.
The latency from Firehose input to Spark input will go up.
If a single file injection into Spark fails (this will happen in a distributed system) you have to shuffle around a huge file, maybe slice it if injection is not atomic, upload it again, all of which could take very long for lots of data. At this point you may find that the time to recover is so long that you'll have to postpone the next injection…
Instead, unless it's impossible in the situation, if you make the Firehose files as small as possible and send them to Spark immediately:
You can archive S3 objects almost immediately, lowering costs.
Data is available in Spark as soon as possible.
If a single file injection into Spark fails there's less data to shuffle around, and if you have automated recovery this shouldn't even be noticeable unless some system is running full tilt at all times (at which point bulk injections would be even worse).
There's a tiny amount of latency increase from establishing TCP connections and authentication.
I'm not familiar with Spark specifically, but in general such a "piped" solution would involve:
A periodic trigger or (even better) an event listener on the Firehose output bucket to process input ASAP.
An injector/transformer to move data efficiently from S3 to Spark. It sounds like Parquet could help with this.
A live Spark/EMR/underlying data service instance ready to receive the data.
In case of an underlying data service, some way of creating a new Spark cluster to query the data on demand.
Of course, if it is not possible to keep Spark data ready (but not queriable ("queryable"? I don't know)) for a reasonable amount of money, this may not be an option. It may also be possible that it's extremely time consuming to inject small chunks of data, but that seems unlikely for a production-ready system.
If you really need to chunk the data into daily dumps you can use multipart uploads. As a comparison, we're doing light processing of several files per minute (many GB per day) from Firehose with no appreciable overhead.
You may create a Lambda function that will be invoked only once a day using Scheduled Events and in your Lambda function you should use Upload Part - Copy that does not need to download your files on the Lambda function. There is already an example of this in this thread

What are different/benefit between S3->Redshift and S3->EMR->Redshift?

I have simple question what are pros/cons for import data from S3 directly into redshift and S3 to redshift via EMR. The reason that I post this question is about If I choose S3->redshift I could do transfrom in redshift using SQL. In other hand If I choose EMR that means using pig/hive or java instead of SQL. Which way I should go?
Thanks.
It depends on the amount of data you have to process and how much of the processing you can offload to Hadoop. Redshift has pretty good performance but it doesn't support too many concurrent operations so data transformation in Redshift may affect your user's querying performance. Also, in Hadoop you can process many types of data and file formats - Redshift is obviously more limited.
I am using S3 -> Redshift, and the performance is pretty good. Like the previous comment, there is a trade off, if you dont want block the user queries, either use Redshift WLM or EMR. In Redshift WLM, your process will be throttled, where as in EMR you will be charged for the aws resources.