Exasol, from the company of the same name in Nuremberg, is presented by the vendor as a high-performance in-memory analytics database that aims to transform how organizations works with data, on-premises, in the cloud or both.
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PostgreSQL
Score 8.5 out of 10
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PostgreSQL (alternately Postgres) is a free and open source object-relational database system boasting over 30 years of active development, reliability, feature robustness, and performance. It supports SQL and is designed to support various workloads flexibly.
Exasol is suited to applications requiring fewer & larger queries (reporting/data analytics/business intelligence tools). Its per-query overhead makes it unsuitable as an operational database (those are optimized for many & smaller queries.)
PostgreSQL, unlike other databases, is user-friendly and uses an open-source database. Ideal for relational databases, they can be accessed when speed and efficiency are required. It enables high-availability and disaster recovery replication from instance to instance. PostgreSQL can store data in a JSON format, including hashes, keys, and values. Multi-platform compatibility is also a big selling point. We could, however, use all the DBMS’s cores. While it works well in fast environments, it can be problematic in slower ones or cause multiple master replication.
We have found Exasol to be very fast at summarizing large data sets. It has been a great backend for both reporting tools and data analytics/business intelligence. Combined with the fact that data import is also very fast it makes it ideal for a real-time ELT architecture.
Exasol is low maintenance. No indexes to maintain (The database auto-manages them) and very little tuning is required.
Query processing is optimized for high throughput and high parallelization. This means that even under high loads performance degrades gracefully as opposed to having "pile-ups" and "meltdowns". This has made it a very reliable database for us.
The stability it offers, its speed of response and its resource management is excellent even in complex database environments and with low-resource machines.
The large amount of resources it has in addition to the many own and third-party tools that are compatible that make productivity greatly increase.
The adaptability in various environments, whether distributed or not, [is a] complete set of configuration options which allows to greatly customize the work configuration according to the needs that are required.
The excellent handling of referential and transactional integrity, its internal security scheme, the ease with which we can create backups are some of the strengths that can be mentioned.
Exasol doesn't have some of the advanced enterprise-y features found in some other large corporate database systems (e.g. native row-level and column-level security). However it's pretty customizable (SQL pre-processing, virtual schemas, powerful user-defined-function frameworks) so many of these features can be implemented manually.
The query syntax for JSON fields is unwieldy when you start getting into complex queries with many joins.
I wish there was a distinction (a flag) you could set for automated scripts vs working in the psql CLI, which would provide an 'Are you sure you want to do X?' type prompt if your query is likely to affect more than a certain number of rows. Especially on updates/deletes. Setting the flag in the headless(scripted) flow would disable the prompt.
Better documentation around JSON and Array aggregation, with more examples of how the data is transformed.
I gave it 9/10 instead of 10/10 only because it lacks in a few advanced enterprise features that require manual workarounds. Otherwise our users have had no problem getting up to speed with it (other than SQL syntax issues that are specific to it, but that's true of any DB)
Postgresql is the best tool out there for relational data so I have to give it a high rating when it comes to analytics, data availability and consistency, so on and so forth. SQL is also a relatively consistent language so when it comes to building new tables and loading data in from the OLTP database, there are enough tools where we can perform ETL on a scalable basis.
The data queries are relatively quick for a small to medium sized table. With complex joins, and a wide and deep table however, the performance of the query has room for improvement.
I have had only positive experiences with their support. They are fast, knowledgeable, and courteous. Online support requests get picked up within hours. I've only once had to use their hotline and that was for an emergency. There was even one minor non-security bug report that I reported and which they fixed in the following week's minor release. I was quite impressed.
There are several companies that you can contract for technical support, like EnterpriseDB or Percona, both first level in expertise and commitment to the software.
But we do not have contracts with them, we have done all the way from googling to forums, and never have a problem that we cannot resolve or pass around. And for dozens of projects and more than 15 years now.
The online training is request based. Had there been recorded videos available online for potential users to benefit from, I could have rated it higher. The online documentation however is very helpful. The online documentation PDF is downloadable and allows users to pace their own learning. With examples and code snippets, the documentation is great starting point.
We looked at some others too, but was 5 yrs ago so I don't recall the list. Exasol had the best performance per cost, outstanding performance, and was easy to evaluate. Even their community addition running on my laptop was faster than our existing reporting solution.
Postgres stacks up just [fine] along the other big players in the RDBMS world. It's very popular for a reason. It's very close to MySQL in terms of cost and features - I'd pick either solution and be just as happy. Compared to Oracle it is a MUCH cheaper solution that is just as usable.
When we first migrated to Exasol (from a MySQL-backed reporting tool) our clients spent over an order of magnitude less time waiting on reports and since then it has opened up possibilities for reporting and analyzing data that were simply not possible beforehand.
The user-role system has saved us tons of time and thus money. As I mentioned in the "Use Case" section, Postgres is not only used by engineering but also finance to measure how much to charge customers and customer support to debug customer issues. Sure, it's not easy for non-technical employees to psql in and view raw tables, but it has saved engineering hundreds of man-hours that would have had to be spent on building equivalent tools to serve finance or customer support.
It provides incredibly trustworthy storage for wherever customer data dumped in. In our 6 years of Postgres existence, we have not lost a byte of customer data due to Postgres messing up a transaction or during the multiple times the hard-drives failed (thanks to ACID compliance!).
This is less significant, but Postgres is also quite easy to manage (unless you are going above and beyond to squeeze out every last bit of performance). There's not much to configure, and the out of the box settings are quite sane. That has saved us engineers lots of time that would have gone into Postgres administration.
