Fix shard weight. Now we can set it to zero

[maxistua]

I can't set the shard weight to zero
We need it for some reasons...

Hopefully this MR will fix that

[UnamedRus]

It's problem with other settings as well AFAIK.
If value is 0, it will not be materialized in xml config by operator

[alex-zaitsev]

Please provide a usage example. Ideally a test, but even example would be helpful.

[maxistua]

Yes, imagine a system where historical data is filled from shard to shard.

And now, when a new shard is added, we need to limit writing to the previous ones.

We can write data directly to the node (which is more efficient in terms of resources), but we can also write it to a distributed table.

So, in order to limit writing to already filled shards, we can set their weight to 0.

Currently, it is not possible to disable writing completely. The minimum weight that can be set is 1.

An example of the desired configuration will be below:

configuration:
  clusters:
    - name: "data-lake"
      secret:
        auto: "True"
      layout:
        shards:
          - name: "1"
            weight: 0 <--
            replicasCount: 1
            ...
          - name: "2"
            weight: 0
            replicasCount: 1
            ...
          - name: "3"
            weight: 0
            replicasCount: 1
            ...
          - name: "4"
            weight: 1
            replicasCount: 1
            ...
          - name: "5"
            weight: 1
            replicasCount: 1
            ...
...

This example will not work because a weight of 0 will be considered an empty value and will not be included in the final configuration.

In this case, the weight of all shards will be equal to 1.

[Slach]

@maxistua thanks for explanation, could you resolve conflicts?

@antip00 could you write test for this use case? which change weight to 0 and insert data into distributed table and check data not inserted into zero-weighted shard?

[sunsingerus]

I'll take a look on this PR

[maxistua]

@maxistua thanks for explanation, could you resolve conflicts?

@antip00 could you write test for this use case? which change weight to 0 and insert data into distributed table and check data not inserted into zero-weighted shard?

@Slach All conflicts have been resolved