# otp.Source.write_iceberg

#### Source.write_iceberg(, catalog_config, table_identifier, output_path, compression_type='snappy', memory_threshold=50, propagate_input_ticks=False, fields_for_disabled_dictionary_encoding=None, inplace=False)

Writes the input tick series into an existing Iceberg table specified by `table_identifier`,
using the catalog settings provided in the `catalog_config` file.

The ticks are written as parquet data files, which are then registered with the Iceberg catalog.
The creation and writing of the parquet files is delegated to
an internal [`write_parquet()`](https://docs.pip.distribution.sol.onetick.com/api/source/write_parquet.html.md#onetick.py.Source.write_parquet) method.

* **Parameters:**
  * **catalog_config** ([*str*](https://docs.pip.distribution.sol.onetick.com/api/operation/str/root.html.md#onetick.py.Operation.str)) -- Path to a configuration file containing the Iceberg catalog parameters.
    For details on the file structure and how it is processed, see Examples below.
  * **table_identifier** ([*str*](https://docs.pip.distribution.sol.onetick.com/api/operation/str/root.html.md#onetick.py.Operation.str)) -- The Iceberg table identifier, including the namespace and table name (for example, `namespace.tablename`).
    The table must already exist.
  * **output_path** ([*str*](https://docs.pip.distribution.sol.onetick.com/api/operation/str/root.html.md#onetick.py.Operation.str)) -- The output location for the parquet data files.
    This value is passed through to the internal [`write_parquet()`](https://docs.pip.distribution.sol.onetick.com/api/source/write_parquet.html.md#onetick.py.Source.write_parquet) method;
    see its `output_path` parameter for the supported path handling
    (writing to a directory or directly to a single file).
  * **compression_type** ([*str*](https://docs.pip.distribution.sol.onetick.com/api/operation/str/root.html.md#onetick.py.Operation.str)) -- Compression algorithm used when writing the parquet files.
    Supported values: gzip, lz4, none, snappy (default), zstd.
  * **memory_threshold** ([*float*](https://docs.pip.distribution.sol.onetick.com/api/operation/float/root.html.md#onetick.py.Operation.float)) -- How much, in megabytes, is buffered per thread before ticks are passed to be written.
    Default: 50
  * **propagate_input_ticks** ([*bool*](https://docs.python.org/3/library/functions.html#bool)) -- If True then ticks will be propagated after this method.
    If False (default) this method won't return ticks.
  * **fields_for_disabled_dictionary_encoding** ([*list*](https://docs.python.org/3/library/stdtypes.html#list)) -- 

    List of fields for which dictionary encoding should be disabled.
    By default, dictionary encoding is enabled for all fields.

    #### NOTE
    This parameter can only be used when the table is partitioned.
  * **inplace** ([*bool*](https://docs.python.org/3/library/functions.html#bool)) -- A flag controls whether operation should be applied inplace.
    If `inplace=True`, then it returns nothing. Otherwise method
    returns a new modified object.
  * **self** ([*Source*](https://docs.pip.distribution.sol.onetick.com/api/source/root.html.md#onetick.py.Source))

#### NOTE
This method requires Java 17 or higher to be installed.
Also Java library path should be added to **PATH** (Windows) or **LD_LIBRARY_PATH** (Linux) environment variables
and to **OMD_JAVALIBPATH** OneTick config variable.

### Examples

Write Iceberg catalog configuration first:

```pycon
>>> with open('catalog.cfg', 'w') as f:
...     f.write('''
...         catalog.name=rest_catalog
...         type=rest
...         uri=http://localhost:8181
...         warehouse=s3://warehouse/
...         s3.region=us-east-1
...         client.region=us-east-1
...         s3.path-style-access=true
...         s3.access-key-id=admin
...         s3.secret-access-key=password
...         io-impl=org.apache.iceberg.aws.s3.S3FileIO
...         s3.delete.enabled=true
...         s3.acceleration-enabled=false
...     ''')
```

Then run the query:

```pycon
>>> data = otp.Tick(A=1)
>>> data = data.write_iceberg(catalog_config='catalog.cfg',
...                           table_identifier='reporting.sales_data',
...                           output_path='sales')
>>> otp.run(data)
```

#### SEE ALSO
**WRITE_TO_ICEBERG** OneTick event processor
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