關於kudu的primary key
The primary key may not be changed after the table is created. You must drop and recreate a table to select a new primary key.
創建之后主鍵列不能變更
The columns which make up the primary key must be listed first in the schema.
否則會報錯：
ImpalaRuntimeException: Error creating Kudu table 'impala::default.cv00_atty_kudu' CAUSED BY: NonRecoverableException: Got out-of-order key column: name: "ent_ts" type: STRING is_key: true is_nullable: false cfile_block_size: 0
The primary key of a row may not be modified using the UPDATE functionality. To modify a row’s primary key, the row must be deleted and re-inserted with the modified key. Such a modification is non-atomic.
主鍵列不能被update
Columns with DOUBLE, FLOAT, or BOOL types are not allowed as part of a primary key definition. Additionally, all columns that are part of a primary key definition must be NOT NULL.
double、float、bool類型字段不能作為主鍵列，同時主鍵列不能為null
Auto-generated primary keys are not supported.
不支持自動生成主鍵
Cells making up a composite primary key are limited to a total of 16KB after the internal composite-key encoding done by Kudu.
主鍵大小最大16k
參考：https://kudu.apache.org/docs/known_issues.html#_schema_and_usage_limitations