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https://issues.apache.org/jira/browse/CASSANDRA-15803?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17715736#comment-17715736
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Stefan Miklosovic commented on CASSANDRA-15803:
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the patch for not failing when ALLOW FILTERING is not used for cases when all
primary keys are specified is here
https://github.com/apache/cassandra/pull/2293/files
So it solve this, until now, this would fail but it does not anymore.
{code}
create table ks.tb (id int, cl1 int, cl2 int, col1 int, primary key ((id), cl1,
cl2))
select * from ks2.tb where id = 1 and cl1 = 2 and cl2 = 3 and col1 = 4;
{code}
This is something different from ALLOW FILTERING [WITHIN PARTITION]. What my
patch fixes is the case when we are selecting on fully enumerated primary key.
There is no reason to require ALLOW FILTERING whatsoever if we _know_ that we
are hitting one row only.
WITHIN PARTITION means that we _know_ that our query is looking into multiple
rows in one partition. WITHIN PARTITION might be used for cases like this:
{code}
create table ks.tb (id int, cl1 int, cl2 int, col1 int, primary key ((id), cl1,
cl2))
select * from ks2.tb where id = 1 and cl1 = 2 and col1 = 3 ALLOW FILTERING
WITHIN PARTITION;
{code}
This is not done yet. I would try to solve it all in this ticket. I created
CASSANDRA-18477 but I realized that it is basically a duplicate and it is
better if this will be all fix in one shot.
> Separate out allow filtering scanning through a partition versus scanning
> over the table
> ----------------------------------------------------------------------------------------
>
> Key: CASSANDRA-15803
> URL: https://issues.apache.org/jira/browse/CASSANDRA-15803
> Project: Cassandra
> Issue Type: Improvement
> Components: CQL/Syntax
> Reporter: Jeremy Hanna
> Priority: Normal
>
> Currently allow filtering can mean two things in the spirit of "avoid
> operations that don't seek to a specific row or sequential rows of data."
> First, it can mean scanning across the entire table to meet the criteria of
> the query. That's almost always a bad thing and should be discouraged or
> disabled (see CASSANDRA-8303). Second, it can mean filtering within a
> specific partition. For example, in a query you could specify the full
> partition key and if you specify a criterion on a non-key field, it requires
> allow filtering.
> The second reason to require allow filtering is significantly less work to
> scan through a partition. It is still extra work over seeking to a specific
> row and getting N sequential rows though. So while an application developer
> and/or operator needs to be cautious about this second type, it's not
> necessarily a bad thing, depending on the table and the use case.
> I propose that we separate the way to specify allow filtering across an
> entire table from specifying allow filtering across a partition in a
> backwards compatible way. One idea that was brought up in Slack in the
> cassandra-dev room was to have allow filtering mean the superset - scanning
> across the table. Then if you want to specify that you *only* want to scan
> within a partition you would use something like
> {{ALLOW FILTERING [WITHIN PARTITION]}}
> So it will succeed if you specify non-key criteria within a single partition,
> but fail with a message to say it requires the full allow filtering. This
> would allow for a backwards compatible full allow filtering while allowing a
> user to specify that they want to just scan within a partition, but error out
> if trying to scan a full table.
> This is potentially also related to the capability limitation framework by
> which operators could more granularly specify what features are allowed or
> disallowed per user, discussed in CASSANDRA-8303. This way an operator could
> disallow the more general allow filtering while allowing the partition scan
> (or disallow them both at their discretion).
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