ClickHouse: How to recreate the Clickhouse metadata in Zookeeper if all Zookeeper data is lost?

Yeah, you can rename them later. And you can backup existing data using freeze https://clickhouse.yandex/docs/en/query_language/alter/#alter_freeze-partition

And use parts from shadow folder.

Steps:

1. create a new replicated table TEMP
2. ALTER TABLE table_name FREEZE
3. mv /var/lib/clickhouse/shadow/…table_name…/* /var/lib/clickhouse/db/TEMP/detached
4. attach all parts / partitions

cd /var/lib/clickhouse/db/TEMP/detached
let i=1;for f in `ls -1` ; do echo $i $f;((i++)); echo "alter table TEMP attach part '$f';"|clickhouse-client ; done

1. rename table_name to table_name_old
2. rename TEMP to table_name
3. rename table_name to table_name_old at replica
4. create a new replicated table table_name at replica (it will download the data)

create a new replicated table table_name at replica (it will download the data)

you need to execute create table at replicas with the same zk path as zk path at the first replicas

@den-crane you mentioned just stop CH. I have data in the temp table (new). I restarted clickhouse and it won’t start, it’s getting an error DB::Exception: Cannot create table from metadata file /var/lib/clickhouse/metadata/default//clicks_sharded_tmp.sql, error: DB::Exception: Existing table metadata in ZooKeeper differs in index granularity byte. I had to delete the ZK path for it to be back up again. 😄

Current state:

• I have the backups of clicks_sharded and the metadata sql file in a temporary directory.
• clicks_sharded and clicks_sharded_old table does not exist now.
• I have no ZK path in zookeeper because of the above.
• I have clicks_sharded_tmp table with the data from attach partition from FREEZING.