Support partitions when migrating to CH

[aadant]

The DDL parser should detect MySQL partitions and migrate them to CH.

MySQL :

create table t(
id int primary key,
dt date not null
) engine=InnoDB
PARTITION BY RANGE  COLUMNS(dt)
(PARTITION p20201231 VALUES LESS THAN ('2021-01-01') ENGINE = InnoDB,
 PARTITION p20211230 VALUES LESS THAN ('2021-12-31') ENGINE = InnoDB,
 PARTITION p20211231 VALUES LESS THAN ('2022-01-03') ENGINE = InnoDB,
 PARTITION p20220103 VALUES LESS THAN ('2022-01-04') ENGINE = InnoDB,
 PARTITION p20220104 VALUES LESS THAN ('2022-01-05') ENGINE = InnoDB,
 PARTITION p20220105 VALUES LESS THAN ('2022-01-06') ENGINE = InnoDB
);

CH :

CREATE TABLE t (id int NULL,
dt Date32 not null,
`_version` UInt64 DEFAULT 0,
`is_deleted` UInt8 DEFAULT 0
) engine=ReplacingMergeTree(_version,is_deleted)  partition by dt order by id

Please note that clickhouse_loader.py already supports this for the initial migration.

[aadant]

It should be possible to override the partitioning key (see #323)

[aadant]

This is already implemented in clickhouse_loader.py
./sink-connector/python/db_load/clickhouse_loader.py

[subkanthi]

Current sink connector parsing logic:

CREATE TABLE t(id Nullable(Int32),dt Date32 NOT NULL ,
`_version` UInt64,`is_deleted` UInt8) Engine=
ReplacingMergeTree(_version,is_deleted) PARTITION BY  (dt) ORDER BY tuple()

[subkanthi]

Parsing of primary key columns added.
Fixed in #379

[Selfeer]

The issue was manually verified by the Altinity QA team and marked as qa-verified.

Build used for testing: altinityinfra/clickhouse-sink-connector:443-678d8ae2567c2c1d89f5430fa57ede619d6ea851-lt

We've verified that when creating a partitioned table in ClickHouse it is correctly mapped to the partitioned table in source MySQL table. Partitions are correctly created in ClickHouse based on the specified partition key.

Issue raised during testing is a separate scenario, which is not related to this one.

Link to the issue: #461