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Standard `table` materialization does not work with ReplicateMergeTree engine

See original GitHub issue

Not sure if this is related to #14 since I didn’t explore the attached PR, but I wanted to call out this problem specifically.

It is my understanding that the way dbt-clickhouse handles table materializations is to:

  1. Rename table (if exists) to {{ this }}__dbt_tmp or something similar (I don’t have the logs in front of me)
  2. Create a new table with name {{ this }}
  3. Drop temp table

With the Replication tables, this results in an error because there already exists a table with the replica path of /clickhouse/tables/{shard}/{database}/{table_name}.

I am currently getting around this using an incremental materialization with a config like:

{{ config(
    engine="ReplicatedMergeTree('/clickhouse/tables/{database}/{table}', '{replica}')",
    pre_hook="truncate table if exists {{ this }} on cluster '...'",
) }}

I’m not sure how we could handle a simple table materialization using the current rename-create-drop strategy since I don’t believe you can update the replica path after creation and I don’t believe there is a random value substitution provided which could potentially allow a replica path like /clickhouse/tables/{shard}/{database}/{table_name}__{random_uuid}

Issue Analytics

  • State:open
  • Created a year ago
  • Reactions:1
  • Comments:5 (2 by maintainers)

github_iconTop GitHub Comments

genzgdcommented, Sep 19, 2022

Tests work with with Replicated database engine so explicit support for ReplicatedMergeTree engines will probably not be a priority.

mharrisb1commented, Dec 4, 2022

@tema-popov I wasn’t aware of that template. That would be a much better solution than mine. I will test it out and update this issue if it works. Thanks!

Read more comments on GitHub >

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