I can’t follow you, sorry.
Are k1 and k2 two column fields?
Is the partition_key a combination of k1 and k2 ?
Is this id field a normal column?
Is this the correct table creation statement as follow ? CREATE TABLE（k1 int，k2 int，id int，PRIMARY KEY(k1，k2));
I’m sorry to trouble you.
The data is written to the data table according to the algorithm corresponding to hash-sharing.
What tools do we have to quickly calculate the hash value of the partition_key?
I want to see how a data record calculates the hash value of the partition_key and writes it to which tablet.
Thank you very much.
You can achieve this by customizing the hash function used for sharding. By default, hash functions distribute data evenly across all shards, so assigning multiple records to the same shard would require modifying the hash function’s behavior.
One approach would be to create a custom hash function that takes the id value and maps it to a specific shard, regardless of the numerical value of id . For instance, you could create a function that always returns 0 for any id value. This would ensure that all records with any id value are placed in the same shard.
Here’s an example of how you might implement this in SQL:
CREATE FUNCTION custom_hash(id INT) RETURNS INT
RETURN 0; -- Always return 0 to place all records in the same shard
CREATE TABLE tracking (
id INT PRIMARY KEY,
-- Other columns...
PARTITION BY HASH(custom_hash(id));
This code defines a custom hash function custom_hash that always returns 0. It then creates a table tracking with a primary key id and partitions the table using the custom hash function. This ensures that all records with any id value are placed in the same shard.
Alternatively, you could use the split into clause to create a single-shard table, which would effectively place all records in the same shard. However, this approach might not be suitable for long-term scalability, as it would limit the ability to distribute data across multiple shards as the data volume grows.
In summary, the most appropriate method for placing records with specific IDs in the same shard depends on your specific requirements and considerations. If you need to ensure that all records with any id value are always placed in the same shard, regardless of the numerical value of id , then customizing the hash function is the most suitable approach. If you anticipate needing to scale the data across multiple shards in the future, then using the split into clause might not be the best choice.