ALTER INDEX to change partitioning settings of indexImplTable

[jepett0]

List of existing tickets on the topic: https://github.com/orgs/ydb-platform/projects/31/views/3?pane=issue&itemId=55226292
Requirements: https://st.yandex-team.ru/KIKIMR-14280

You can read the whole story in the RFC, but the gist of it is provided below.

Previously, there was no available instrument to alter partitioning settings of an index table in spite of the often arising need to do so. It could only be done by superusers (i.e. users listed in AdministrationAllowedSIDs of the cluster; usually just the YDB staff) with either a public API request, or by sending a private SchemeShard's ModifyScheme protobuf. No YQL syntax was available for use even for the superusers (indexImplTable is hidden and cannot be a target of ALTER TABLE request).

We decided to provide users with a way to conveniently alter partitioning settings of an index table. It seems that the most needed options is to set AUTO_PARTITIONING_MIN_PARTITIONS_COUNT to a higher value to prepare for the future load on the index.

Syntax

ALTER TABLE table_name ALTER INDEX index_name SET partitioning_setting_name value
ALTER TABLE table_name ALTER INDEX index_name SET (partitioning_setting_name_1 = value_1, ...)

table_name - the name of the table, whose index is to be altered

index_name - the name of the index to be altered

[github-actions]

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Test history

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72420	59712	0	6	12691	11

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Test history

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
13479	13227	0	60	167	25

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[ijon]

This condition is hard to read and comprehend.

[jepett0]

Will try to simplify it in a follow-up PR

[ijon]

Why cases with requests with explicit tokens are gone? Check for admin token in alter table is still there.

[jepett0]

Yes, the check for superuser is still present in CreateConsistentAlterTable, but the purpose has changed. Currently, every user with AlterScheme permission can alter PartitionConfig.PartitioningPolicy of indexImplTable and superusers can alter any setting of indexImplTable (like they did before).

This particular test, in my opinion, is focused more on the effects of altering PartitionConfig of indexImplTable, then on the permissions of superusers. I think the best solution would be to add another unit test to show the difference between superusers and regular users. In fact, I have already added such a unit test in KQP, but not in SchemeShard.

I will add a similar test in SchemeShard in a follow-up PR.