[DocDB] ALTER command fails after hitting the tablet guardrail limit.

[massifcoder-yb]

Jira Link: DB-13627

Description

Steps:

• Hitting the tablet guardrail limit.
• Increase the tablet guardrail limit.
• Insert a large amount of data in tables.
• Hit the tablet guardrail limit.
• ALTER command to set a columns as not null.

Failed with error:

Invalid table definition: Error creating table tablet_guardrail_pitr_1.employee_hash on the master: The requested number of tablet replicas (69) would cause the total running tablet replica count (2268) to exceed the safe system maximum (2190)

Artifacts: https://drive.google.com/file/d/1k0W604pvSCuuDgwvOSPodrZsEpZ8QWbQ/view?usp=drive_link

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[druzac]

Some ALTER commands under the hood create a new table and replace the existing table with the new one. This involves creating a new set of tablets to back the new table. When the cluster is at its limit of supportable tablets, the tablet guardrail feature will block the creation of the new table.