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Updated docs on front coding (#13387)

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Jill Osborne 2022-11-19 08:01:04 +00:00 committed by GitHub
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docs/ingestion/ingestion-spec.md
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@ -486,7 +486,7 @@ The `indexSpec` object can include the following properties:
Front coding is an experimental feature starting in version 25.0. Front coding is an incremental encoding strategy that Druid can use to store STRING and [COMPLEX<json>](../querying/nested-columns.md) columns. It allows Druid to create smaller UTF-8 encoded segments with very little performance cost.
To enable front coding with SQL-based ingestion, define an `indexSpec` in a query context. See [SQL-based ingestion reference](../multi-stage-query/reference.md#context-parameters) for more information.
You can enable front coding with all types of ingestion. For information on defining an `indexSpec` in a query context, see [SQL-based ingestion reference](../multi-stage-query/reference.md#context-parameters).
> Front coding is new to Druid 25.0 so the current recommendation is to enable it in a staging environment and fully test your use case before using in production. Segments created with front coding enabled are not compatible with Druid versions older than 25.0.

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docs/multi-stage-query/reference.md
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@ -202,7 +202,7 @@ The following table lists the context parameters for the MSQ task engine:
| `segmentSortOrder` | INSERT or REPLACE<br /><br />Normally, Druid sorts rows in individual segments using `__time` first, followed by the [CLUSTERED BY](#clustered-by) clause. When you set `segmentSortOrder`, Druid sorts rows in segments using this column list first, followed by the CLUSTERED BY order.<br /><br />You provide the column list as comma-separated values or as a JSON array in string form. If your query includes `__time`, then this list must begin with `__time`. For example, consider an INSERT query that uses `CLUSTERED BY country` and has `segmentSortOrder` set to `__time,city`. Within each time chunk, Druid assigns rows to segments based on `country`, and then within each of those segments, Druid sorts those rows by `__time` first, then `city`, then `country`. | empty list |
| `maxParseExceptions`| SELECT, INSERT, REPLACE<br /><br />Maximum number of parse exceptions that are ignored while executing the query before it stops with `TooManyWarningsFault`. To ignore all the parse exceptions, set the value to -1.| 0 |
| `rowsPerSegment` | INSERT or REPLACE<br /><br />The number of rows per segment to target. The actual number of rows per segment may be somewhat higher or lower than this number. In most cases, use the default. For general information about sizing rows per segment, see [Segment Size Optimization](../operations/segment-optimization.md). | 3,000,000 |
| `indexSpec` | INSERT or REPLACE<br /><br />An [`indexSpec`](../ingestion/ingestion-spec.md#indexspec) to use when generating segments. May be a JSON string or object. | See [`indexSpec`](../ingestion/ingestion-spec.md#indexspec). |
| `indexSpec` | INSERT or REPLACE<br /><br />An [`indexSpec`](../ingestion/ingestion-spec.md#indexspec) to use when generating segments. May be a JSON string or object. See [Front coding](../ingestion/ingestion-spec.md#front-coding) for details on configuring an `indexSpec` with front coding. | See [`indexSpec`](../ingestion/ingestion-spec.md#indexspec). |
## Durable Storage
This section enumerates the advantages and performance implications of enabling durable storage while executing MSQ tasks.