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PR fixes: update documentation on JSONCompactWithProgress format

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Alexey Korepanov 2024-08-23 21:42:54 +02:00
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docs/en/interfaces/formats.md
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@ -930,7 +930,43 @@ Columns that are not present in the block will be filled with default values (yo
In this format, ClickHouse outputs each row as a separated, newline-delimited JSON Object.
Each row is either a metadata object, data object, progress information or statistics object.
Each row is either a metadata object, data object, progress information or statistics object:
1. **Metadata Object (`meta`)**
- Describes the structure of the data rows.
- Fields: `name` (column name), `type` (data type, e.g., `UInt32`, `String`, etc.).
- Example: `{"meta": [{"name":"id", "type":"UInt32"}, {"name":"name", "type":"String"}]}`
- Appears before any data objects.
2. **Data Object (`data`)**
- Represents a row of query results.
- Fields: An array with values corresponding to the columns defined in the metadata.
- Example: `{"data":["1", "John Doe"]}`
- Appears after the metadata object, one per row.
3. **Progress Information Object (`progress`)**
- Provides real-time progress feedback during query execution.
- Fields: `read_rows`, `read_bytes`, `written_rows`, `written_bytes`, `total_rows_to_read`, `result_rows`, `result_bytes`, `elapsed_ns`.
- Example: `{"progress":{"read_rows":"8","read_bytes":"168"}}`
- May appear intermittently.
4. **Statistics Object (`statistics`)**
- Summarizes query execution statistics.
- Fields: `rows`, `rows_before_limit_at_least`, `elapsed`, `rows_read`, `bytes_read`.
- Example: `{"statistics": {"rows":2, "elapsed":0.001995, "rows_read":8}}`
- Appears at the end.
5. **Exception Object (`exception`)**
- Represents an error that occurred during query execution.
- Fields: A single text field containing the error message.
- Example: `{"exception": "Code: 395. DB::Exception: Value passed to 'throwIf' function is non-zero..."}`
- Appears when an error is encountered.
6. **Totals Object (`totals`)**
- Provides the totals for each numeric column in the result set.
- Fields: An array with total values corresponding to the columns defined in the metadata.
- Example: `{"totals": ["", "3"]}`
- Appears at the end of the data rows, if applicable.
Example: