parquet export docs

documentation/reference/api/rest.md

@@ -591,15 +591,33 @@ returned in a tabular form to be saved and reused as opposed to JSON.
 `/exp` is expecting an HTTP GET request with following parameters:
 
 | Parameter | Required | Description                                                                                                                                                                                                                  |
-| :-------- | :------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+|:----------|:---------|:-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | `query`   | Yes      | URL encoded query text. It can be multi-line.                                                                                                                                                                                |
 | `limit`   | No       | Paging opp parameter. For example, `limit=10,20` will return row numbers 10 through to 20 inclusive and `limit=20` will return first 20 rows, which is equivalent to `limit=0,20`. `limit=-20` will return the last 20 rows. |
 | `nm`      | No       | `true` or `false`. Skips the metadata section of the response when set to `true`.                                                                                                                                            |
+| `fmt`     | No       | Export format. Valid values: `parquet`, `csv`. When set to `parquet`, exports data in Parquet format instead of CSV.                                                                                                         |
+
+#### Parquet Export Parameters
+
+When `fmt=parquet`, the following additional parameters are supported:
+
+| Parameter            | Required | Default         | Description                                                                                         |
+|:---------------------|:---------|:----------------|:----------------------------------------------------------------------------------------------------|
+| `partition_by`       | No       | `NONE`          | Partition unit: `NONE`, `HOUR`, `DAY`, `WEEK`, `MONTH`, or `YEAR`.                                  |
+| `compression_codec`  | No       | `LZ4_RAW`       | Compression algorithm: `UNCOMPRESSED`, `SNAPPY`, `GZIP`, `LZ4`, `ZSTD`, `LZ4_RAW`, `BROTLI`, `LZO`. |
+| `compression_level`  | No       | Codec-dependent | Compression level (codec-specific). Higher values = better compression but slower.                  |
+| `row_group_size`     | No       | `100000`        | Number of rows per Parquet row group.                                                               |
+| `data_page_size`     | No       | `1048576`       | Size of data pages in bytes (default 1MB).                                                          |
+| `statistics_enabled` | No       | `true`          | Enable Parquet column statistics: `true` or `false`.                                                |
+| `parquet_version`    | No       | `2`             | Parquet format version: `1` (v1.0) or `2` (v2.0).                                                   |
+| `raw_array_encoding` | No       | `true`          | Use raw encoding for arrays: `true` or `false`.                                                     |
 
 The parameters must be URL encoded.
 
 ### Examples
 
+#### CSV Export (default)
+
 Considering the query:
 
 ```shell
@@ -620,6 +638,44 @@ A HTTP status code of `200` is returned with the following response body:
 200501BS00005,"2005-01-10T00:00:00.000Z",21:13
 ```
 
+#### Parquet Export
+
+Export query results to Parquet format:
+
+```shell
+curl -G \
+  --data-urlencode "query=SELECT * FROM trades WHERE timestamp IN today()" \
+  --data-urlencode "fmt=parquet" \
+  http://localhost:9000/exp > trades_today.parquet
+```
+
+#### Parquet Export with Custom Options
+
+Export with custom compression and partitioning:
+
+```shell
+curl -G \
+  --data-urlencode "query=SELECT * FROM trades" \
+  --data-urlencode "fmt=parquet" \
+  --data-urlencode "partition_by=DAY" \
+  --data-urlencode "compression_codec=ZSTD" \
+  --data-urlencode "compression_level=9" \
+  --data-urlencode "row_group_size=1000000" \
+  http://localhost:9000/exp > trades.parquet
+```
+
+#### Parquet Export with LZ4 Compression
+
+Export with LZ4_RAW compression for faster export:
+
+```shell
+curl -G \
+  --data-urlencode "query=SELECT symbol, price, amount FROM trades WHERE timestamp > dateadd('h', -1, now())" \
+  --data-urlencode "fmt=parquet" \
+  --data-urlencode "compression_codec=LZ4_RAW" \
+  http://localhost:9000/exp > recent_trades.parquet
+```
+
 ## Error responses
 
 ### Malformed queries

documentation/reference/function/meta.md

@@ -589,6 +589,50 @@ If you want to re-read metadata for all user tables, simply use an asterisk:
 SELECT hydrate_table_metadata('*');
 ```
 
+## copy_export_log
+
+`copy_export_log()` or `sys.copy_export_log` returns the export log for `COPY TO` operations.
+
+**Arguments:**
+
+- `copy_export_log()` does not require arguments.
+
+**Return value:**
+
+Returns metadata on `COPY TO` export operations for the last three days, including columns such as:
+
+- `ts` - timestamp of the log event
+- `id` - export identifier that can be used to track export progress
+- `table` - source table name (or 'query' for subquery exports)
+- `destination` - destination directory path for the export
+- `format` - export format (currently only 'PARQUET')
+- `status` - event status: 'started', 'finished', 'failed', or 'cancelled'
+- `message` - error message when status is 'failed'
+- `rows_exported` - total number of exported rows (shown in final log row)
+- `partition` - partition name for partitioned exports (null for non-partitioned)
+
+**Examples:**
+
+```questdb-sql
+SELECT * FROM copy_export_log();
+```
+
+| ts                          | id               | table  | destination   | format  | status   | message | rows_exported | partition  |
+| --------------------------- | ---------------- | ------ | ------------- | ------- | -------- | ------- | ------------- | ---------- |
+| 2024-10-01T14:23:15.123456Z | 7f3a9c2e1b456789 | trades | trades_export | PARQUET | started  |         | 0             | null       |
+| 2024-10-01T14:25:42.987654Z | 7f3a9c2e1b456789 | trades | trades_export | PARQUET | finished |         | 1000000       | null       |
+
+```questdb-sql title="Track specific export"
+SELECT * FROM copy_export_log() WHERE id = '7f3a9c2e1b456789';
+```
+
+```questdb-sql title="View recent failed exports"
+SELECT ts, table, destination, message
+FROM copy_export_log()
+WHERE status = 'failed'
+ORDER BY ts DESC;
+```
+
 ## flush_query_cache()
 
 `flush_query_cache' invalidates cached query execution plans.