Re: Should we use Materialised Views or ditch them ?

[Erick Ramirez]

I received quite a number of follow up questions directly as a result of my
response to Tobias' question. My comments on MVs specifically only relate
to MVs in OSS C*. :)

I'd like to reiterate that my responses to this mailing list are almost
exclusively relating to OSS C* but I'm going to make an exception and
address the questions about DataStax Enterprise (DSE) since I'm continually
getting asked about it. Particularly on this point:

But know the limitations
>
>
> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/knownLimitationsMV.html
>

That page is for an old version of DSE. There have been several
enhancements/improvements/fixes in DSE that is not included in Apache
Cassandra... *yet*. Thanks to Paulo Motta, Zhao Yang & co who improved MVs
in DSE so it works with Graph. Note the stark contrast when compared to the
DSE 6.7 version of that page --
https://docs.datastax.com/en/dse/6.7/cql/cql/cql_using/knownLimitationsMV.html
.

Having said that, the situation where a view becomes permanently
out-of-sync with the base table is still outstanding in both DSE & OSS C*.
The workaround remains the same -- drop the view and recreate it. Again,
usual caveats apply and YMMV. Cheers!

GOT QUESTIONS? Apache Cassandra experts from the community and DataStax
have answers! Share your expertise on https://community.datastax.com/.

Re: Should we use Materialised Views or ditch them ?

[Anthony Grasso]

Hi Tobias,

I have had a similar experiences to Jon where I have seen Materialized
Views cause major issues in clusters. I too recommend avoiding them.

Regards,
Anthony

On Sat, 29 Feb 2020 at 07:37, Jon Haddad  wrote:

> I also recommend avoiding them.  I've seen too many clusters fall over as
> a result of their usage.
>
> On Fri, Feb 28, 2020 at 9:52 AM Max C.  wrote:
>
>> The general view of the community is that you should *NOT* use them in
>> production, due to multiple serious outstanding issues (see Jira).  We used
>> them quite a bit when they first came out and have since rolled back all
>> uses except for the absolute most basic cases (ex:  a table with 30K rows
>> that isn’t updated).  If we were to do it over, we would not use them at
>> all.
>>
>> - Max
>>
>> On Feb 28, 2020, at 7:07 am, Tobias Eriksson 
>> wrote:
>>
>> Hi
>>  A debate has surfaced in my company, whether to keep or remove
>> Materialized Views
>> The Datastax FAQ says sure thing, go ahead and use it
>> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/faqMV.html
>> But know the limitations
>>
>> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/knownLimitationsMV.html
>> and best practices
>>
>> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/bestPracticesMV.html
>>
>> What is the community take on using MV(Materialized Views) in production ?
>>
>> -Tobias
>>
>>
>>

Re: Should we use Materialised Views or ditch them ?

[Johnny Miller]

I have had some serious issues with MVs in production - I would
recommend not using them.

On Fri, 28 Feb 2020 at 22:34, Erick Ramirez 
wrote:

> Personally, I think MVs are still experimental and not ready for
> primetime. It works for some but if you run into issues, fixing them have a
> huge impact to your application. For example if the view updates get too
> far behind, there's no effective way to resolve them other than having to
> drop the MV then add it back in so it gets rebuilt from scratch which means
> that the view is not available to your application for some time.
>
> There are some improvements coming in 4.0 (unreleased) but you've got to
> test it at scale before deploying it to production. For now, I'd stay away
> from it. YMMV. Cheers!
>
> GOT QUESTIONS? Apache Cassandra experts from the community and DataStax
> have answers! Share your expertise on https://community.datastax.com/.
>
>>

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Re: Should we use Materialised Views or ditch them ?

[Erick Ramirez]

Personally, I think MVs are still experimental and not ready for primetime.
It works for some but if you run into issues, fixing them have a huge
impact to your application. For example if the view updates get too far
behind, there's no effective way to resolve them other than having to drop
the MV then add it back in so it gets rebuilt from scratch which means that
the view is not available to your application for some time.

There are some improvements coming in 4.0 (unreleased) but you've got to
test it at scale before deploying it to production. For now, I'd stay away
from it. YMMV. Cheers!

GOT QUESTIONS? Apache Cassandra experts from the community and DataStax
have answers! Share your expertise on https://community.datastax.com/.

>

Re: Should we use Materialised Views or ditch them ?

[Tobias Eriksson]

It is interresting, cause when they arrived we started using them, but then 
there surfaced some posts on issues, even Datastax seemed to indicate that you 
shouldn’t use them
But now lately, from the articles/blogposts below, it seems like that is not 
the case anymore….
I wonder if there has been significant work done here to improve or even solve 
the problems
-Tobias

From: Jon Haddad 
Reply to: "user@cassandra.apache.org" 
Date: Friday, 28 February 2020 at 21:37
To: "user@cassandra.apache.org" 
Subject: Re: Should we use Materialised Views or ditch them ?

I also recommend avoiding them.  I've seen too many clusters fall over as a 
result of their usage.

On Fri, Feb 28, 2020 at 9:52 AM Max C. 
mailto:mc_cassan...@core43.com>> wrote:
The general view of the community is that you should *NOT* use them in 
production, due to multiple serious outstanding issues (see Jira).  We used 
them quite a bit when they first came out and have since rolled back all uses 
except for the absolute most basic cases (ex:  a table with 30K rows that isn’t 
updated).  If we were to do it over, we would not use them at all.

- Max


On Feb 28, 2020, at 7:07 am, Tobias Eriksson 
mailto:tobias.eriks...@qvantel.com>> wrote:

Hi
 A debate has surfaced in my company, whether to keep or remove Materialized 
Views
The Datastax FAQ says sure thing, go ahead and use it
https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/faqMV.html
But know the limitations
https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/knownLimitationsMV.html
and best practices
https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/bestPracticesMV.html

What is the community take on using MV(Materialized Views) in production ?

-Tobias

Re: Should we use Materialised Views or ditch them ?

[Jon Haddad]

I also recommend avoiding them.  I've seen too many clusters fall over as a
result of their usage.

On Fri, Feb 28, 2020 at 9:52 AM Max C.  wrote:

> The general view of the community is that you should *NOT* use them in
> production, due to multiple serious outstanding issues (see Jira).  We used
> them quite a bit when they first came out and have since rolled back all
> uses except for the absolute most basic cases (ex:  a table with 30K rows
> that isn’t updated).  If we were to do it over, we would not use them at
> all.
>
> - Max
>
> On Feb 28, 2020, at 7:07 am, Tobias Eriksson 
> wrote:
>
> Hi
>  A debate has surfaced in my company, whether to keep or remove
> Materialized Views
> The Datastax FAQ says sure thing, go ahead and use it
> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/faqMV.html
> But know the limitations
>
> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/knownLimitationsMV.html
> and best practices
> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/bestPracticesMV.html
>
> What is the community take on using MV(Materialized Views) in production ?
>
> -Tobias
>
>
>

Re: Should we use Materialised Views or ditch them ?

[Max C.]

The general view of the community is that you should *NOT* use them in 
production, due to multiple serious outstanding issues (see Jira).  We used 
them quite a bit when they first came out and have since rolled back all uses 
except for the absolute most basic cases (ex:  a table with 30K rows that isn’t 
updated).  If we were to do it over, we would not use them at all.

- Max

> On Feb 28, 2020, at 7:07 am, Tobias Eriksson  
> wrote:
> 
> Hi 
>  A debate has surfaced in my company, whether to keep or remove Materialized 
> Views
> The Datastax FAQ says sure thing, go ahead and use it
> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/faqMV.html 
> 
> But know the limitations
> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/knownLimitationsMV.html
>  
> 
> and best practices
> https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/bestPracticesMV.html 
> 
>  
> What is the community take on using MV(Materialized Views) in production ?
>  
> -Tobias

Should we use Materialised Views or ditch them ?

[Tobias Eriksson]

Hi
 A debate has surfaced in my company, whether to keep or remove Materialized 
Views
The Datastax FAQ says sure thing, go ahead and use it
https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/faqMV.html
But know the limitations
https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/knownLimitationsMV.html
and best practices
https://docs.datastax.com/en/dse/5.1/cql/cql/cql_using/bestPracticesMV.html

What is the community take on using MV(Materialized Views) in production ?

-Tobias