opened Pull Request #3205 on apache/cassandra
#3205 Add properties for redirecting build-resolve to mirrors
opened Pull Request #3204 on apache/cassandra
#3204 Add properties for redirecting build-resolve to mirrors
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Abraços
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Espero que goste.
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Mais um livro seu pra colocar aqui na minha playlist 😃😃😃
Answered Allow filter in cassandra query
Some basics: One should never use ALLOW FILTERING in your read queries as that is a bad practice because of the following reasons,
- This table data model is not designed appropriately based on the application access...
Some basics: One should never use ALLOW FILTERING in your read queries as that is a bad practice because of the following reasons,
- This table data model is not designed appropriately based on the application access pattern
- AF will perform a scan of the entire distributed table
Having said that, it may be okay here in this scenario as you're already providing the full primary keys [partition keys + clustering keys] of the table here and it'd be a no-op for AF.
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It was a selfie.
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Answered Allow filter in cassandra query
Since you're filtering by the primary key columns, ALLOW FILTERING is redundant. When you filter by partition key and (optionally) clustering column(s), the coordinator will know which replicas store the data, and each of the...
Since you're filtering by the primary key columns, ALLOW FILTERING is redundant. When you filter by partition key and (optionally) clustering column(s), the coordinator will know which replicas store the data, and each of the contacted replicas will infer through local indexing where the data is stored at the storage level, making it an efficient Cassandra read query.
In opposition, when the ALLOW FILTERING query doesn't filter by all terms of the partition key, and/or filters by non-primary key columns, local replica indexing and/or global indexing will be rendered useless, making it so that a large set of replicas scan their full dataset and filter after reading - thus inefficient.
The purpose of the ALLOW FILTERING option is to exceptionally allow queries that require a full scan, since this type of query fails by default, as a safeguard, due to the impact risks.
I have one table
CREATE TABLE user (
p1 int,
p2 int,
created_at timestamp,
user_name text,
c1 text,
PRIMARY KEY ((p1, p2),user_name)
) WITH additional_write_policy = '99p';
what will...
I have one table
CREATE TABLE user (
p1 int,
p2 int,
created_at timestamp,
user_name text,
c1 text,
PRIMARY KEY ((p1, p2),user_name)
) WITH additional_write_policy = '99p';
what will happen if i will run query
select * from user where p1 = 1 and p2 = 1 and user_name = 'abc' allow filtering;
will allow filtering will work here or it's just redundant in query .
The term "unrepaired" may seem ambiguous given what repairs are meant to do, but what you see is expected.
The distinction...
The term "unrepaired" may seem ambiguous given what repairs are meant to do, but what you see is expected.
The distinction between repaired and unrepaired bytes lies in the metadata upon which incremental repairs depend.
FULL REPAIR
When you run the repair command you issued (in 4.0 and above) with --full, Cassandra marks all the data covered by the scope of the repair as "unrepaired" at the sstable metadata level - this makes the distinction between full and incremental repairs.
INCREMENTAL REPAIR
When you run an incremental repair instead, Cassandra marks all the repaired data as "repaired", also at the sstable level - The goal of this feature is to skip the "repaired" sstables in future repair sessions, minimizing repair overhead.
This effectively creates 2 pools of sstables behind the scenes, where repaired sstables can only be compacted with other repaired sstables, while the same logic applies to their unrepaired counterparts, in order to retain the consistency of repair status metadata.
So that you don't have to be locked in into only full or incremental repairs, Cassandra always keeps the repaired metadata accordingly, depending on which repair strategy you opt for.
Reportedly, previous bugs with incremental repairs were addressed in Cassandra 4.0, and in most cases it's worth running incremental repairs in Cassandra 4 and above, with some periodic full repairs in between. This is specially true if repair runs impact your services/application - incremental repairs can save you a ton of repair time.
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