So I have some historical data on S3 in .csv/.parquet format. Everyday I have my batch job running which gives me 2 files having the list of data that needs to be deleted from the historical snapshot, and the new records that needs to be inserted to the historical snapshot. I cannot run insert/delete queries on athena. What are the options (cost effective and managed by aws) do I have to execute my problem?
Objects in Amazon S3 are immutable. This means that be replaced, but they cannot be edited.
Amazon Athena, Amazon Redshift Spectrum and Hive/Hadoop can query data stored in Amazon S3. They typically look in a supplied path and load all files under that path, including sub-directories.
To add data to such data stores, simply upload an additional object in the given path.
To delete all data in one object, delete the object.
However, if you wish to delete data within an object, then you will need to replace the object with a new object that has those rows removed. This must be done outside of S3. Amazon S3 cannot edit the contents of an object.
See: AWS Glue adds new transforms (Purge, Transition and Merge) for Apache Spark applications to work with datasets in Amazon S3
Data Bricks has a product called Delta Lake that can add an additional layer between queries tools and Amazon S3:
Delta Lake is an open source storage layer that brings reliability to data lakes. Delta Lake provides ACID transactions, scalable metadata handling, and unifies streaming and batch data processing. Delta Lake runs on top of your existing data lake and is fully compatible with Apache Spark APIs.
Delta Lake supports deleting data from a table because it sits "in front of" Amazon S3.
Related
I have a bunch of tables in DynamoDB (80 right now but can grow in future) and looking to sync data from these tables to either Redshift or S3 (using Glue on top of it to query using Athena) for running analytics query.
There are also very frequent updates (to existing entries) and deletes happen in the DynamoDB tables which I want to sync along with addition of newer entries.
Checked the Write capacity units (WCU) consumed for all tables and the rate is coming out to be around 35-40 WCU per second at peak times.
Solutions I considered:
Use Kinesis Firehose along with lambda (which reads updates from DDB streams) to push data to Redshift in small batches (Issue: it cannot support updates and deletes and is only good for adding new entries because it uses Redshift COPY command under the hood to upload data to Redshift)
Use Lambda (which reads updates from DDB streams) to copy data to S3 directly as json with each entry being a separate file. This can support updates and deletes if we have S3 filepath same as primary key of DynamoDB tables (Issue: It will result in tons of small files in S3 which might not scale for querying using AWS Glue)
Use Lambda (which reads updates from DDB streams) to update data to Redshift directly as soon as a new update happens. (Issue: Too many small writes to Redshift can cause scaling issues for Redshift as it is more suited for batch writes/updates)
My Amazon S3 path is as follows:
s3://dev-mx-allocation-storage/ph_test_late_waiver/{year}/{month}/{day}/{flow_number}*.csv
I need to create a pipeline from S3 to Snowflake where for each day of the month a new csv file would fall into the bucket and that csv file should be inserted into a snowflake table.
I am very new to this, can I please get a command in snowflake which can do that?
Snowpipe lends itself well to real-time requirements of data, as it loads data based on triggers and can manage vast and continuous loading. Data volumes and the compute/storage resources to load data are managed by the Snowflake cloud, which is why it is promoted as a serverless feature. If it’s one less thing to manage, all the better to focus our energies on our own application development!
Step by step guide: https://medium.com/#walton.cho/auto-ingest-snowpipe-on-s3-85a798725a69
I am using BigQuery Data Transfer Service to migrate all data from redshift to bigquery.
After that, i want to perform backfilling for specific time, if any data is missing. But i don't see any backfilling option in Transfer job.
How can i achieve that in bigquery?
Reading your question under the light of your comments I would proceed differently from what you describe. You reach the same goal however :) .
Using your ETL pipeline, the first step would be to accumulate raw data in a datalake.
Let's take a storage service like S3 to do so. For this ETL pipeline, S3 is your datasink.
Note that your pipeline does nothing more than taking raw data from A to put it into S3. Also, the location in S3 should be under a timestampted folder on day for instance (e.g: yyyymmdd) so that you can sort and consume your data on time dimension.
Obviously the considered data is ahead in time from the one you already have in Redshift.
Maybe it is also a different structure from the one you already put in redshift due to potential transformation you set in your initial pipeline.
In case you set raw data directly into redshift, then just export the data into the same S3 bucket under the name legacy/*. (In case it is transformed, then you have to put a second S3 datasink in your pipeline with this intermediary transformation an keep the same S3 naming strategy).
Let's take a break to understand what we have. We filled an S3 bucket with raw data that we can now replay at will on a specific day using a cron or an orchestrating tool such as Apache Airflow. Moreover you can freely modified the content of each timestamped folder in case you missed data to replay the following pipelines => the backfill you want.
Speaking of which, S3 would act as a data source for these following pipelines that would set wanted transformations on the raw data from S3 and choose BigQuery and potentially Redshift as Datasink. Now please take in consideration the price of these operations. Streaming API in BQ is expensive. As high of 0.50$ per Gb. Do that only if you need real time result. If you can afford latency of more than 5 minutes a better strategy would to set GCS as the datasink of your ETL and transfer the data from there into BQ (note to put the data in the same file naming pattern yyyymmdd to enable potential backfill). This transfer is free if GCS bucket and BQ dataset are in the same region. You would trigger the transfer with GCS events for instance (trigering a cloud function on blob creation that put the data into BQ).
Last but not least, backfilling should be done wisely especially in BQ where update or creation at row level is not peformant and is an open door for duplication. What you should consider is BigQuery partition that you can set on a column that contains a timestamp or an hidden one if your data contains none. Which timestamp? Well the one set in GCS folder name!
Once again you can modify data in your GCS bucket per day and replay the transfer into BQ.
But each transfer from a given day must overwrtite the partition the considered data belongs to. (e.g: the data under 20200914 would overwrite the associated partition in BQ. We abide by the concept of pure task doing so which a guarantee for idempotency and non duplication).
Please read this article to have more insights.
Note: If you intend to get rid off Redshit, you can choose to do it directly and forget about S3 as a datasink of your first ETL. Choose directly GCS (ingress is free) and migrate your already present Redshift data into GCS using S3 as an intermediary service and the Google transfer service from S3 to GCS.
We are trying to take our data from an AWS S3 (external stage) and load it into a Snowflake internal stage. Snowflake should act as our data lake, and can reduce the amount of storage we use from AWS. Is there any built in functionality that can transfer data from external stage --> internal stage?
The goal is to load the data into the internal Snowflake stage and subsequently delete the data from AWS. We want Snowflake to be the data lake.
What do you mean internal stage?
If you are planning to load into Snowflake tables, your scenario is perfect use case for Snowpipe, for more info Automating Snowpipe for Amazon S3
An internal stage would just be a different S3 bucket utilized by Snowflake. So it's not really "reducing" the amount of storage, just changing its location. If you still wanted to do this, you could GET from your external stage and PUT to the internal stage. Or you could just load from the external stage to your tables in Snowflake via any of the available methods.
You've got to stop thinking that a "data lake" means a bunch of raw data files stored in a cloud bucket somewhere. That's the 2010 version of a data lake.
In Snowflake, you can load the raw data into tables that mirror those files (either structured column-by-column, or semi-structured JSON,XML,Parquet...). Think of these tables as your "raw" zone. With Streams and Tasks, you can automate the curation of the data in the raw zone into a second set of tables - the "curated" zone. Another set of Streams/Tasks might go another step and pre-aggregate the curated data into an "aggregated" zone. The design of the workflows is up to you.
The cloud storage just becomes a "landing area" for raw extracted data, and can be deleted after ingestion into Snowflake. You now have a single platform for your raw data, curated data, and aggregated data. Hook up a data governance tool like Alation or Collibra to maintain the lineage of the data through its journey.
-Paul-
I see there is tons of examples and documentation to copy data from DynamoDB to Redshift, but we are looking at an incremental copy process where only the new rows are copied from DynamoDB to Redshift. We will run this copy process everyday, so there is no need to kill the entire redshift table each day. Does anybody have any experience or thoughts on this topic?
Dynamo DB has a feature (currently in preview) called Streams:
Amazon DynamoDB Streams maintains a time ordered sequence of item
level changes in any DynamoDB table in a log for a duration of 24
hours. Using the Streams APIs, developers can query the updates,
receive the item level data before and after the changes, and use it
to build creative extensions to their applications built on top of
DynamoDB.
This feature will allow you to process new updates as they come in and do what you want with them, rather than design an exporting system on top of DynamoDB.
You can see more information about how the processing works in the Reading and Processing DynamoDB Streams documentation.
The copy from redshift can only copy the entire table. There are several ways to achieve this
Using an AWS EMR cluster and Hive - If you set up an EMR cluster then you can use Hive tables to execute queries on the dynamodb data and move to S3. Then that data can be easily moved to redshift.
You can store your dynamodb data based on access patterns (see http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/GuidelinesForTables.html#GuidelinesForTables.TimeSeriesDataAccessPatterns). If we store the data this way, then the dynamodb tables can be dropped after they are copied to redshift
This can be solved with a secondary DynamoDB table that tracks only the keys that were changed since the last backup. This table has to be updated wherever initial DynamoDB table is updated (add, update, delete). At the end of a backup process you will delete them or after you backup a row (one by one).
If your DynamoDB table can have
Timestamps as an attribute or
A binary flag which conveys data freshness as attribute
then you can write a hive query to export only current day's data or fresh data to s3 and then 'KEEP_EXISTING' copy this incremental s3 data to Redshift.