ZooKeeper schema


Table schema.

date column -> legacy MergeTree partition expression.
sampling expression -> SAMPLE BY
index granularity -> index_granularity
mode -> type of MergeTree table
sign column -> sign - CollapsingMergeTree / VersionedCollapsingMergeTree
primary key -> ORDER BY key if PRIMARY KEY not defined.
sorting key -> ORDER BY key if PRIMARY KEY defined.
data format version -> 1
partition key -> PARTITION BY
granularity bytes -> index_granularity_bytes

types of MergeTree tables:
Ordinary            = 0
Collapsing          = 1
Summing             = 2
Aggregating         = 3
Replacing           = 5
Graphite            = 6
VersionedCollapsing = 7


Log of latest mutations


List of columns for latest (reference) table version. Replicas would try to reach this state.


Log of latest actions with table.

Related settings:

 max_replicated_logs_to_keep  1000         0  How many records may be in log, if there is inactive replica. Inactive replica becomes lost when when this number exceed.                                                   UInt64 
 min_replicated_logs_to_keep  10           0  Keep about this number of last records in ZooKeeper log, even if they are obsolete. It doesn't affect work of tables: used only to diagnose ZooKeeper log before cleaning. │ UInt64 │


List of table replicas.



Pointer to the latest mutation executed by replica


Pointer to the latest task from replication_queue executed by replica



Table schema of specific replica


Columns list of specific replica.


Used for quorum inserts.

Last modified 2022.01.17: Update zookeeper-schema.md (1fe7453)