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Documentation for insert_deduplication_token setting

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The setting was introduced in #32304
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Igor Nikonov 2022-02-13 20:52:13 +01:00 committed by GitHub
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docs/en/operations/settings/settings.md
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@ -1803,6 +1803,20 @@ If an INSERTed block is skipped due to deduplication in the source table, there
At the same time, this behaviour “breaks” `INSERT` idempotency. If an `INSERT` into the main table was successful and `INSERT` into a materialized view failed (e.g. because of communication failure with Zookeeper) a client will get an error and can retry the operation. However, the materialized view won’t receive the second insert because it will be discarded by deduplication in the main (source) table. The setting `deduplicate_blocks_in_dependent_materialized_views` allows for changing this behaviour. On retry, a materialized view will receive the repeat insert and will perform a deduplication check by itself,
ignoring check result for the source table, and will insert rows lost because of the first failure.
## insert_deduplication_token {#insert_deduplication_token}
The setting allows a user to provide own deduplication semantic in MergeTree/ReplicatedMergeTree
For example, by providing a unique value for the setting in each INSERT statement,
user can avoid the same inserted data being deduplicated
Possilbe values:
- Any string
Default value: empty string (disabled)
`insert_deduplication_token` is used for deduplication _only_ when not empty
## max_network_bytes {#settings-max-network-bytes}
Limits the data volume (in bytes) that is received or transmitted over the network when executing a query. This setting applies to every individual query.