[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[
https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13854697#comment-13854697
]
Alex P commented on CASSANDRA-5633:
---
Some extensions of SQL (T-SQL, PLSQL) support {{IF ELSE}} statements. So
another way to do this could be:
{code}
IF (condition) THEN
BEGIN BATCH
APPLY BATCH
{code}
The only "advantages" of this approach would be:
1. a structure that is familiar
2. is just an extension of the current {{BATCH}}
> CQL support for updating multiple rows in a partition using CAS
> ---
>
> Key: CASSANDRA-5633
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5633
> Project: Cassandra
> Issue Type: Improvement
>Affects Versions: 2.0 beta 1
>Reporter: sankalp kohli
>Assignee: Sylvain Lebresne
>Priority: Minor
> Labels: cql3
> Fix For: 2.0.4
>
>
> This is currently supported via Thrift but not via CQL.
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[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13850698#comment-13850698 ] Sebastian Schmidt commented on CASSANDRA-5633: -- This indeed seems to be a solution to our problem and we could certainly model our data using this approach. I am not sold that we need to introduce yet another concept just for syntactic ease, but this solution does offer us a very straightforward way to specify this specific CAS use case. > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 beta 1 >Reporter: sankalp kohli >Assignee: Sylvain Lebresne >Priority: Minor > Labels: cql3 > Fix For: 2.0.4 > > > This is currently supported via Thrift but not via CQL. -- This message was sent by Atlassian JIRA (v6.1.4#6159)
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
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]
Sylvain Lebresne commented on CASSANDRA-5633:
-
I'm starting to wonder if another approaches to this wouldn't be simpler.
Namely, I'd like to suggest the idea of supporting "static" columns (the
initial idea was suggested by jhalliday on irc). That is, we allow to declare
some columns that as "static" to a partition, i.e. their value would be shared
by all the rows of the same partition. The reason this is related to this issue
is that you could CAS those static columns to update multiple rows of the same
partition atomically.
Concretely, you could define something like that:
{noformat}
CREATE TABLE t (
id text PRIMARY KEY,
version int static,
insertion_time timeuuid,
prop1 text,
prop2 int,
PRIMARY KEY (insertion_time, prop1, prop2)
)
{noformat}
The {{version}} column being static, it's value would be shared by all rows
having the same {{id}} so that you can use it as a "partition version" that
allows to serialize inserts. More precisely, you'd read some row(s) of the
partition, and update some other row of the partition based on CASing the
version just read.
Though it's not 100% equivalent to what the other suggestion of this ticket, I
believe this "static" solution would be as general as anything else in terms of
what can be done since you can serialize updates in any order you want. And in
fact, for every concrete use case I have in mind for this ticket, this static
column solution seems to provide a more natural/direct solution (of course,
it's quite possible there is use cases I haven't though of and for which this
"static columns" idea would be very awkward, but I'd be happy to understand
those).
Other advantages of this static columns solution I can think of are that:
# it doesn't require any complex syntax. We'll have to define a few rules to
govern those static columns (when do they get deleted, etc..), but syntax wise,
it would really all just be the introduction of the "static" keyword in table
creation.
# it has uses outside of CAS, making it less of a narrow use case. There are
cases where people want to basically cram a static and a dynamic table into a
single table for efficiency reasons, and this would provide a "native" way to
support that.
I'll soon open a separate issue for this "static columns" idea, with a bit more
detail on the exact semantic and some pointers on how I think this can be
implemented, but [~sebastian_schmidt], is that something which sounds like it
would fit well to your use cases? (and if not, can you try to explain why, if
only for the sake of better understanding what we're trying to solve here).
> CQL support for updating multiple rows in a partition using CAS
> ---
>
> Key: CASSANDRA-5633
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5633
> Project: Cassandra
> Issue Type: Improvement
>Affects Versions: 2.0 beta 1
>Reporter: sankalp kohli
>Assignee: Sylvain Lebresne
>Priority: Minor
> Labels: cql3
> Fix For: 2.0.4
>
>
> This is currently supported via Thrift but not via CQL.
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[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13848238#comment-13848238 ] Sebastian Schmidt commented on CASSANDRA-5633: -- We are pretty much stuck with Hector right now and would like to move to CQL once this gets implemented. Our use case is not very specific, but we are trying to model data that contains relationships that need to be updated atomically. Using CAS through CQL makes it impossible for us to use atomic updates, which can easily break our constraints. We believe that any data model that contains dependencies or relationships requires such a functionality should CAS be used as an op-lock mechanism. As a suggestion for syntax, we have the following to offer: update cf set c='a', d='b' where foo='a' and bar = 'b', set c='x', d='y' where foo='a' and bar = 'c' if (bar='b' and c='d’), (bar='g' and c='h’); where the table is: CREATE TABLE cf ( foo text, bar text, c text, d text, PRIMARY KEY (foo, bar) ) > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 beta 1 >Reporter: sankalp kohli >Assignee: Sylvain Lebresne >Priority: Minor > Labels: cql3 > Fix For: 2.0.4 > > > This is currently supported via Thrift but not via CQL. -- This message was sent by Atlassian JIRA (v6.1.4#6159)
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13822246#comment-13822246 ] Sylvain Lebresne commented on CASSANDRA-5633: - I'm also quite reluctant in adding some sub-query syntax "just for this", mainly for the cons expresses above, that is 1) the fact that it confuses quite a bit the "we don't do sub-query" message and 2) it doesn't make it very clear what the restrictions on that sub-query are. Which is not to say that I have a much better idea. But maybe a better understanding of what this could be useful for in practice could help here? Granted "thrift can do it" is one type of argument, but outside that, a concrete CQL3 example of why this could be useful could help might help making some progress? > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 beta 1 >Reporter: sankalp kohli >Assignee: Sylvain Lebresne >Priority: Minor > Labels: cql3 > Fix For: 2.0.3 > > > This is currently supported via Thrift but not via CQL. -- This message was sent by Atlassian JIRA (v6.1#6144)
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682770#comment-13682770 ] Jonathan Ellis commented on CASSANDRA-5633: --- Well, that's the point -- you only get one condition w/ CAS so that should be explicit in the syntax. > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 >Reporter: sankalp kohli >Priority: Minor > Labels: cql3 > Fix For: 2.0 > > > This is currently supported via Thrift but not via CQL. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682766#comment-13682766 ] Aleksey Yeschenko commented on CASSANDRA-5633: -- This looks all right with '...', but specifying multiple conditions here is going to be truly verbose with IF (SELECT ...) = ... AND ... > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 >Reporter: sankalp kohli >Priority: Minor > Labels: cql3 > Fix For: 2.0 > > > This is currently supported via Thrift but not via CQL. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[
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]
Jonathan Ellis commented on CASSANDRA-5633:
---
I submit that a more regular extention of batch for the former would be
{code}
BEGIN BATCH
UPDATE FOO ...
UPDATE FOO ...
APPLY BATCH IF ...
{code}
> CQL support for updating multiple rows in a partition using CAS
> ---
>
> Key: CASSANDRA-5633
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5633
> Project: Cassandra
> Issue Type: Improvement
>Affects Versions: 2.0
>Reporter: sankalp kohli
>Priority: Minor
> Labels: cql3
> Fix For: 2.0
>
>
> This is currently supported via Thrift but not via CQL.
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[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682755#comment-13682755 ] Jonathan Ellis commented on CASSANDRA-5633: --- Agreed, although I only have a specific use case for the latter. > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 >Reporter: sankalp kohli >Priority: Minor > Labels: cql3 > Fix For: 2.0 > > > This is currently supported via Thrift but not via CQL. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682733#comment-13682733 ] Aleksey Yeschenko commented on CASSANDRA-5633: -- bq. I don't see how this solves the problem of "I want to CAS row X based on the value of row Y." Your example looks more like 3 separate operations each of which has CAS-in-same-row. True. But to match thrift api you are going to need both the ability to update several rows in a single cas operation *and* the ability to refer to other rows within the same partition in conditions. > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 >Reporter: sankalp kohli >Priority: Minor > Labels: cql3 > Fix For: 2.0 > > > This is currently supported via Thrift but not via CQL. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682720#comment-13682720 ] Jonathan Ellis commented on CASSANDRA-5633: --- bq. Maybe some new kind of BATCH, CAS BATCH? I don't see how this solves the problem of "I want to CAS row X based on the value of row Y." Your example looks more like 3 separate operations each of which has CAS-in-same-row. > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 >Reporter: sankalp kohli >Priority: Minor > Labels: cql3 > Fix For: 2.0 > > > This is currently supported via Thrift but not via CQL. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682515#comment-13682515 ] Jonathan Ellis commented on CASSANDRA-5633: --- Well, given that we have someone who's pretty likely to go live with this in Thrift, and we tell people that CQL exposes everything you can do from Thrift, I don't like that solution either. :) > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 >Reporter: sankalp kohli >Priority: Minor > Labels: cql3 > Fix For: 2.0 > > > This is currently supported via Thrift but not via CQL. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
[ https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682505#comment-13682505 ] Aleksey Yeschenko commented on CASSANDRA-5633: -- I like this even less :( Maybe we shouldn't expose it to cql at all, if it doesn't fit the language? > CQL support for updating multiple rows in a partition using CAS > --- > > Key: CASSANDRA-5633 > URL: https://issues.apache.org/jira/browse/CASSANDRA-5633 > Project: Cassandra > Issue Type: Improvement >Affects Versions: 2.0 >Reporter: sankalp kohli >Priority: Minor > Labels: cql3 > Fix For: 2.0 > > > This is currently supported via Thrift but not via CQL. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira
[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
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https://issues.apache.org/jira/browse/CASSANDRA-5633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13682496#comment-13682496
]
Jonathan Ellis commented on CASSANDRA-5633:
---
How about this?
{code}
UPDATE foo SET x = 10 WHERE bar = 1
IF (SELECT y FROM foo WHERE baz = 2) = 3
{code}
Pro:
# Good match with semantics of what CAS actually does under the hood
# Fairly natural for SQL users
Con:
# Need to invent syntax for multiple columns ({{IF (SELECT y, z ...) = (3, 4)}})
# Risks confusing people who wonder why we don't support subqueries elsewhere
> CQL support for updating multiple rows in a partition using CAS
> ---
>
> Key: CASSANDRA-5633
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5633
> Project: Cassandra
> Issue Type: Improvement
>Affects Versions: 2.0
>Reporter: sankalp kohli
>Priority: Minor
> Labels: cql3
> Fix For: 2.0
>
>
> This is currently supported via Thrift but not via CQL.
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[jira] [Commented] (CASSANDRA-5633) CQL support for updating multiple rows in a partition using CAS
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]
Aleksey Yeschenko commented on CASSANDRA-5633:
--
We only support updating several rows using BATCH in cql3, so this would
somehow involve BATCH as well.
Maybe some new kind of BATCH, CAS BATCH?
{noformat}
BEGIN CAS BATCH
UPDATE foo SET x = 10 WHERE bar = 1 AND baz = 'k' IF x = 9
UPDATE foo SET y = 15 WHERE bar = 1 AND baz = 'y' IF y = 7
DELETE FROM foo WHERE bar = 1 AND baz = 'z' IF NOT EXISTS
APPLY BATCH
{noformat}
We'll validate the partition key is the same (bar) and merge all the conditions
together (all the updates, too) and it will only apply if all the conditions
are true.
Not all statements even have to involve CAS, but at least one should.
It's not perfect, just the first thing that came to mind.
> CQL support for updating multiple rows in a partition using CAS
> ---
>
> Key: CASSANDRA-5633
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5633
> Project: Cassandra
> Issue Type: Improvement
>Affects Versions: 2.0
>Reporter: sankalp kohli
>Priority: Minor
> Labels: cql3
> Fix For: 2.0
>
>
> This is currently supported via Thrift but not via CQL.
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