> Elastic has been working on this gap. The more recent ES|QL introduces a similar feature called lookup joins, and Elastic SQL provides a more familiar syntax (with no joins). But these are still bound by Lucene’s underlying index model. On top of that, developers now face a confusing sprawl of overlapping query syntaxes (currently: Query DSL, ES|QL, SQL, EQL, KQL), each suited to different use cases, and with different strengths and weaknesses.
I suppose we need a new rule, "Any sufficiently successful data store eventually sprouts at least one ad hoc, informally-specified, inconsistency-ridden, slow implementation of half of a relational database"
Funny argument on the query languages in hindsight, since the latest release (https://www.paradedb.com/blog/paradedb-0-20-0 but that was after this blog) just completely changed the API. To be seen how many different API versions you get if you make it to 15 years ;)
PS: I've worked at Elastic for a long time, so it is fun to see the arguments for a young product.
Are the folks still using ES simply unaware of the performance advantages of ClickHouse, or is there some use case that ES covers that CH is still missing?
Accenture managed to build a data platform for my company with Elasticsearch as the primary database. I raised concerns early during the process but their software architect told me they never had any issues. I assume he didn’t lie. I was only an user so I didn’t fight and decided to not make my work rely on their work.
I worked in a company that used elastic search as main db.
It worked, company made alot of money from that project. It was a wrong decision but helped us complete the project very fast. We needed search capability and a db. ES did it both.
Problems that we faced by using elastic search:
High load, high Ram usage : db goes down, more ram needed. Luckily we had ES experts in infra team, helped us alot.(ecommerce company)
To Write and read after, you need to refresh the index or wait a refresh.
More inserts, more index refreshes. Which ES is not designed for, inserts become slow. You need to find a way to insert in bulk.
Api starts, cannot find es alias because of connection issue, creates a new alias(our code did that when it cant find alias, bad idea). Oops whole data on alias is gone.
Most important thing to use ES as main db is to use "keyword" type for every field that you don't text search.
No transaction: if second insert fails you need to delete first insert by hand. Makes code look ugly.
Advantages: you can search, every field is indexed, super fast reads. Fast development. Easy to learn. We never faced data loss, even if db crashed.
ES should be thought of as a json key value store and search engine. The json key value store is fully consistent and supports read after write semantics, refresh is needed for search api. In some cases it does make sense to treat it as a database provided the key value store semantics is enough.
I used it about 7 years ago. Text search was not that heavily used, but we utilized the keyword filter heavily. It's like having a database where you can throw any query at it and it would return a response in reasonable time, because you are just creating an index on all fields.
Databases and search engines have different engineering priorities, and data integrity is not a top tier priority for search engine developers because a search engine is assumed not to be the primary data store. Search engines are designed to build an index which augments a data store and which can be regenerated when needed.
Anyone in engineering who recommends using a search engine as a primary data store is taking on risk of data loss for their organization that most non-engineering people do not understand.
In one org I worked for, we put the search engine in front of the database for retrieval, but we also made sure that the data was going to Postgres.
> Anyone in engineering who recommends using a search engine as a primary data store is taking on risk of data loss for their organization.
It is true that Elasticsearch was not designed for it, but there is no reason why another "search engine" designed for that purpose couldn't fit that role.
agree with comment. We use ES quite extensively as a database with huge documents and touchwood we haven't had any data loss. We take hourly backups and it is simple to restore.
You have to get used to eventual consistency. If you want to read after writing even by id, you have to wait for the indexing to be complete (around 1 second).
You have to design the documents in such a way that you shouldn't need to join the data with anything else. So make sure you have all the data you need for the document inside it. In an SQL db you would normalize the data and then join. Here assume you have only one table and put all the data inside the doc.
But as we evolved and added more and more fields into the document, the document sizes have grown a lot (Megabytes) and hitting limits like (max searchable fields :1000 can be increased but not recommended) search buffer limits 100MB).
My take is that ES is good for exploration and faster development but should switch to SQL as soon the product is successful if you're using it as the main db.
I’ve either been involved with or adjacent to dozens of Accenture projects at 5 companies over the last 20 years, and not a single one had a satisfactory outcome.
I’ve never heard a single story of “Accenture came in, and we got what we wanted, on time and on budget.” Cases of “we got a minimum viable solution for $100m instead of $30m, and it was four years late” seem more typical.
It's just that they're only seeing money to build and a place to make excuses on being late.
If you hire your own people you can make them feel how well the business is doing and get features out the door tomorrow and build to the larger thing over time.
I've seen some mess-ups in my life, but they started sticking out like a sore thumb long, long, long, long before anywhere close to $30 million was spent on it.
Teams of consultants on site, some remote, and many offshore. Tons of documents are created and many environments and DevOps pipelines are stood up. First code release is when the people who push buttons touch the system for the first time. It is crap. Several more code releases attempt to make the system usable. Eventually another consultant or two are brought to evaluate the project and they say the project violated every best practice and common sense rule. Most egregiously the internal stakeholders who voiced serious concerns at the beginning of the project were dismissed or forced out etc.
So much the same as what I've seen before, except instead of abandoning ship when the mess was clear and present, doubling down to see how far of a hole one can dig? Sunk cost must be one hell of a drug for the aforementioned CTO.
"A $30 million mess-up" can look like (at least) two things. It can be $30 million was spent on a project that earned $0 revenue and was ultimately canceled, or it can look like $x was spent on a project to win a $30 million contract but a competitor won the contract instead.
I really never understood how people could store very important information in ES like it was a database.
Even if they don't understand what ES is and what a "normal" database is, I'm sure some of those people run into issues where their "db" got either corrupted of lost data even when testing and building their system around it. This is and was general knowledge at the time, it was no secret that from time to time things got corrupted and indexes needed to be rebuilt.
Doesn't happen all the time, but way greater than zero times and it's understandable because Lucene is not a DB engine or "DB grade" storage engine, they had other more important things to solve in their domain.
So when I read stories of data loss and things going South, I don't have sympathy for anyone involved other than the unsuspecting final clients. These people knew or more or less knew and choose to ignore and be lazy.
> I really never understood how people could store very important information in ES like it was a database.
I agree.
Its been a while since I touched it, but as far as I can remember ES has never pretended to be your primary store of information. It was mostly juniors that reached for it for transaction processing, and I had to disabuse them of the notion that it was fit for purpose there.
ES is for building a searchable replica of your data. Every ES deployment I made or consulted sourced its data from some other durable store, and the only thing that wrote to it were replication processes or backfills.
usually in companies, people have a main durable store of information that is then streamed to other databases that store a transformation of this data with some augmentation.
these new data stores don't usually require that level of durability or reliability.
we had something like this to scale out for higher throughput. just in the 10's of thousands requests per second required 100+ nodes simply because each query would have a expensive scatter and gather
No, of course not. But the question is, do you need a database?
A database is a big proposition: transactions, indexes, query processing, replication, distribution, etc. A fair number of use cases are just "Take this data and give it back to me when I ask for it".
ES (or any other not-a-database) might not be a full-bore DBMS. But it might be what you need.
Rule of thumb: Whenever you think you don't need relational database features, you will later discover why you do.
The one thing relational databases don't have, that you might need, is scaling. Maintaining data consistency implies a certain level of non-concurrency. Conversely, maintaining perfect concurrency implies a certain level of data inconsistency.
The other thing relational databases don't have, that you are definitely going to need, is a practical implementation.
You could maybe consider Rel if you have a particular type of workload, but, realistically, just use a tablational database. It will be a lot easier and is arguably better.
Ofcourse it is not meant as a primary database. What baffles me is that people use it as log storage. As an application scales, storage and querying logs become the bottleneck if elasticsearch is used. I was dealing with a system that could afford only 1 week of log retention!
Logs are always notoriously expensive to store and also are notorious for accidentally exposing PII, API/private/db keys, etc. They should generally only be stored for a relatively short period of time at scale. In fact, to remain compliant to CCPA, 28 days is the safe number for most things.
Metrics are much more efficient and are the tool of choice for longer term storage and debugging.
”That means a recently acknowledged write may not show up until the next refresh.”
Which is why you supply the parameter
refresh: ”wait_for”
in your writes. This forces a refresh and waits for it to happen before completing the request.
”schema migrations require moving the entire system of record into a new structure, under load, with no safety net”
Use index aliases. Create new index using the new mapping, make a reindex request from old index to new one. When it finishes, change the alias to point to the new index.
The other criticisms are more valid, but not entirely: for example, no database ”just works” without carefully tuning the memory-related configuration for your workload, schema and data.
It took me years before I started tuning the memory-related configuration of postgres for workload, schema and data, in any way. It "just works" for the first ten thousand concurrent users.
Well, most people working on a car don’t have a car lift: it only makes sense when you need to safely work on a large volume of cars. If you only work on one or two, a jack and a pile of wood works just fine.
Please don't move the goal post. Writing `no database ”just works” without (...)` is gatekeeping behavior, creating an image of complexity that for most use cases - especially for those starting out - just doesn't exist.
it's the other way around: `wait_for` waits for the next refresh (there is configurable refresh interval, 1s by default), `refresh: true` forces refresh without waiting for the next refresh interval.
the difference is that waiting for refresh assures that the data will be available for search after the "insert" finishes. forcing refresh might be foot gun that will criple the servers.
It's not so much that Elastic is saying it as a lot of people doing the supposed wrong the advert-article describes.
I've seen some examples of people using ES as a database, which I'd advise against for pretty much the reasons TFA brings up, unless I can get by on just a YAGNI reasoning.
It will also depend a lot on the type of data: Logs are an easy yes. Something that required multi-document transactions (unless you're able to structure it differently) is a harder tradeoff. Though loss of ACKed documents shouldn't really be a thing any more.
I work in infosec and several popular platforms use elasticsearch for log storage and analysis.
I would never. Ever. Bet my savings on ES being stable enough to always be online to take in data, or predictable in retaining the data it took in.
It feels very best-effort and as a consultant, I recommend orgs use some other system for retaining their logs, even a raw filesystem with rolling zips, before relying on ES unless you have a dedicated team constantly monitoring it.
Do you happen to know if ES was the only storage? Its been almost 8 years, but if I was building a log storage and analysis system, then I'd push the logs to S3 or some other object store and build an ES index off of that S3 data. From the consumer's perspective, it may look like we're using ES to store the data, but we have a durable backup to regenerate ES if necessary.
Even most toy databases "built in a weekend" can be very stable for years if:
- No edge-case is thrown at them
- No part of the system is stressed ( software modules, OS,firmware, hardware )
- No plug is pulled
Crank the requests to 11 or import a billion rows of data with another billion relations and watch what happens. The main problem isn't the system refusing to serve a request or throwing "No soup for you!" errors, it's data corruption and/or wrong responses.
To be fair, I think it is chronically underprovisioned clusters that get overwhelmed by log forwarding. I wasn't on the team that managed the ELK stack a decade ago, but I remember our SOC having two people whose full time job was curating the infrastructure to keep it afloat.
Now I work for a company whose log storage product has ES inside, and it seems to shit the bed more often than it should - again, could be bugs, could be running "clusters" of 1 or 2 instead of 3.
> Let's not turn the word database into a buzzword.
It is much too late for that, but you're right that we'd be wise to put effort into undoing that. This is exactly how you end up with people using Elasticsearch as a primary datastore. When someone hears that they need a database, a database is what you are going to see them pick.
If we regularly used the proper terminology with appropriate specificity then those without the deep technical knowledge required to understand all the different kinds of databases and the tradeoffs that come them are able to narrow their search to the solutions that fit within the specification.
it now has dedicated index types for logs and metrics with all kinds of sugar and tweaks in default behavior, they should introduce a new one called "database" that's acid.
I suppose we need a new rule, "Any sufficiently successful data store eventually sprouts at least one ad hoc, informally-specified, inconsistency-ridden, slow implementation of half of a relational database"
PS: I've worked at Elastic for a long time, so it is fun to see the arguments for a young product.
Problems that we faced by using elastic search: High load, high Ram usage : db goes down, more ram needed. Luckily we had ES experts in infra team, helped us alot.(ecommerce company)
To Write and read after, you need to refresh the index or wait a refresh. More inserts, more index refreshes. Which ES is not designed for, inserts become slow. You need to find a way to insert in bulk.
Api starts, cannot find es alias because of connection issue, creates a new alias(our code did that when it cant find alias, bad idea). Oops whole data on alias is gone.
Most important thing to use ES as main db is to use "keyword" type for every field that you don't text search.
No transaction: if second insert fails you need to delete first insert by hand. Makes code look ugly.
Advantages: you can search, every field is indexed, super fast reads. Fast development. Easy to learn. We never faced data loss, even if db crashed.
I used it about 7 years ago. Text search was not that heavily used, but we utilized the keyword filter heavily. It's like having a database where you can throw any query at it and it would return a response in reasonable time, because you are just creating an index on all fields.
Anyone in engineering who recommends using a search engine as a primary data store is taking on risk of data loss for their organization that most non-engineering people do not understand.
In one org I worked for, we put the search engine in front of the database for retrieval, but we also made sure that the data was going to Postgres.
It is true that Elasticsearch was not designed for it, but there is no reason why another "search engine" designed for that purpose couldn't fit that role.
My take is that ES is good for exploration and faster development but should switch to SQL as soon the product is successful if you're using it as the main db.
They messed up a $30 million dollar project big time at a previous company. My cto swore to never recommend them
I’ve either been involved with or adjacent to dozens of Accenture projects at 5 companies over the last 20 years, and not a single one had a satisfactory outcome.
I’ve never heard a single story of “Accenture came in, and we got what we wanted, on time and on budget.” Cases of “we got a minimum viable solution for $100m instead of $30m, and it was four years late” seem more typical.
If you hire your own people you can make them feel how well the business is doing and get features out the door tomorrow and build to the larger thing over time.
What does a $30 million dollar mess-up look like?
"A $30 million mess-up" can look like (at least) two things. It can be $30 million was spent on a project that earned $0 revenue and was ultimately canceled, or it can look like $x was spent on a project to win a $30 million contract but a competitor won the contract instead.
Even if they don't understand what ES is and what a "normal" database is, I'm sure some of those people run into issues where their "db" got either corrupted of lost data even when testing and building their system around it. This is and was general knowledge at the time, it was no secret that from time to time things got corrupted and indexes needed to be rebuilt.
Doesn't happen all the time, but way greater than zero times and it's understandable because Lucene is not a DB engine or "DB grade" storage engine, they had other more important things to solve in their domain.
So when I read stories of data loss and things going South, I don't have sympathy for anyone involved other than the unsuspecting final clients. These people knew or more or less knew and choose to ignore and be lazy.
I agree.
Its been a while since I touched it, but as far as I can remember ES has never pretended to be your primary store of information. It was mostly juniors that reached for it for transaction processing, and I had to disabuse them of the notion that it was fit for purpose there.
ES is for building a searchable replica of your data. Every ES deployment I made or consulted sourced its data from some other durable store, and the only thing that wrote to it were replication processes or backfills.
Best example is IoT marketing, as if it can handle the load without bazillion shards, and since when does a text engine want telemetry
these new data stores don't usually require that level of durability or reliability.
Feel like the christmas story kid --
>simplicity, and world-class performance, get started with XXXXXXXX.
A crummy commercial?
And it was good for a lot of things.
A database is a big proposition: transactions, indexes, query processing, replication, distribution, etc. A fair number of use cases are just "Take this data and give it back to me when I ask for it".
ES (or any other not-a-database) might not be a full-bore DBMS. But it might be what you need.
The one thing relational databases don't have, that you might need, is scaling. Maintaining data consistency implies a certain level of non-concurrency. Conversely, maintaining perfect concurrency implies a certain level of data inconsistency.
You could maybe consider Rel if you have a particular type of workload, but, realistically, just use a tablational database. It will be a lot easier and is arguably better.
Metrics are much more efficient and are the tool of choice for longer term storage and debugging.
Which is why you supply the parameter
in your writes. This forces a refresh and waits for it to happen before completing the request.”schema migrations require moving the entire system of record into a new structure, under load, with no safety net”
Use index aliases. Create new index using the new mapping, make a reindex request from old index to new one. When it finishes, change the alias to point to the new index.
The other criticisms are more valid, but not entirely: for example, no database ”just works” without carefully tuning the memory-related configuration for your workload, schema and data.
the difference is that waiting for refresh assures that the data will be available for search after the "insert" finishes. forcing refresh might be foot gun that will criple the servers.
(Obviously I'm referring to a famous YouTube video on the subject)
I've seen some examples of people using ES as a database, which I'd advise against for pretty much the reasons TFA brings up, unless I can get by on just a YAGNI reasoning.
I would never. Ever. Bet my savings on ES being stable enough to always be online to take in data, or predictable in retaining the data it took in.
It feels very best-effort and as a consultant, I recommend orgs use some other system for retaining their logs, even a raw filesystem with rolling zips, before relying on ES unless you have a dedicated team constantly monitoring it.
- No edge-case is thrown at them
- No part of the system is stressed ( software modules, OS,firmware, hardware )
- No plug is pulled
Crank the requests to 11 or import a billion rows of data with another billion relations and watch what happens. The main problem isn't the system refusing to serve a request or throwing "No soup for you!" errors, it's data corruption and/or wrong responses.
Now I work for a company whose log storage product has ES inside, and it seems to shit the bed more often than it should - again, could be bugs, could be running "clusters" of 1 or 2 instead of 3.
Elastic’s own consultants will tell you this …
Turns out running complicated large distributed systems requires a bit more than a ./apply, who would have guessed it?
It should obviously NOT be a "main" database but part of an ETL pipeline for search purposes for instance.
It is much too late for that, but you're right that we'd be wise to put effort into undoing that. This is exactly how you end up with people using Elasticsearch as a primary datastore. When someone hears that they need a database, a database is what you are going to see them pick.
If we regularly used the proper terminology with appropriate specificity then those without the deep technical knowledge required to understand all the different kinds of databases and the tradeoffs that come them are able to narrow their search to the solutions that fit within the specification.
> who
Do not fall into the trap of anthropomorphizing Larry Ellison!
https://www.youtube.com/watch?v=-zRN7XLCRhc&t=2300s