feat: add optimize command in python binding

python/deltalake/table.py

@@ -313,6 +313,29 @@ def vacuum(
 
         return self._table.vacuum(dry_run, retention_hours, enforce_retention_duration)
 
+    def optimize(
+        self,
+        partition_filters: Optional[List[Tuple[str, str, Any]]] = None,
+        target_size: Optional[int] = None,
+    ) -> Dict[str, Any]:
+        """
+        Compacts small files to reduce the total number of files in the table.
+
+        This operation is idempotent; if run twice on the same table (assuming it has
+        not been updated) it will do nothing the second time.
+
+        If this operation happens concurrently with any operations other than append,
+        it will fail.
+
+        :param partition_filters: the partition filters that will be used for getting the matched files
+        :param target_size: desired file size after bin-packing files, in bytes. If not
+          provided, will attempt to read the table configuration value ``delta.targetFileSize``.
+          If that value isn't set, will use default value of 256MB.
+        :return: the metrics from optimize
+        """
+        metrics = self._table.optimize(partition_filters, target_size)
+        return json.loads(metrics)
+
     def pyarrow_schema(self) -> pyarrow.Schema:
         """
         Get the current schema of the DeltaTable with the Parquet PyArrow format.

python/docs/source/usage.rst

@@ -399,7 +399,23 @@ only list the files to be deleted. Pass ``dry_run=False`` to actually delete fil
 Optimizing tables
 ~~~~~~~~~~~~~~~~~
 
-Optimizing tables is not currently supported.
+Optimizing a table will perform bin-packing on a Delta Table which merges small files
+into a large file. Bin-packing reduces the number of API calls required for read operations.
+Optimizing will increments the table's version and creates remove actions for optimized files.
+Optimize does not delete files from storage. To delete files that were removed, call :meth:`DeltaTable.vacuum`.
+
+Use :meth:`DeltaTable.optimize` to perform the optimize operation. Note that this method will fail if a
+concurrent writer performs an operation that removes any files (such as an overwrite).
+
+.. code-block:: python
+
+    >>> dt = DeltaTable("../rust/tests/data/simple_table")
+    >>> dt.optimize()
+    {'numFilesAdded': 1, 'numFilesRemoved': 5,
+     'filesAdded': {'min': 555, 'max': 555, 'avg': 555.0, 'totalFiles': 1, 'totalSize': 555},
+     'filesRemoved': {'min': 262, 'max': 429, 'avg': 362.2, 'totalFiles': 5, 'totalSize': 1811},
+     'partitionsOptimized': 1, 'numBatches': 1, 'totalConsideredFiles': 5,
+     'totalFilesSkipped': 0, 'preserveInsertionOrder': True}
 
 Writing Delta Tables
 --------------------

python/src/lib.rs

@@ -16,6 +16,7 @@ use deltalake::builder::DeltaTableBuilder;
 use deltalake::checkpoints::create_checkpoint;
 use deltalake::datafusion::prelude::SessionContext;
 use deltalake::delta_datafusion::DeltaDataChecker;
+use deltalake::operations::optimize::OptimizeBuilder;
 use deltalake::operations::transaction::commit;
 use deltalake::operations::vacuum::VacuumBuilder;
 use deltalake::partitions::PartitionFilter;
@@ -314,6 +315,28 @@ impl RawDeltaTable {
         Ok(metrics.files_deleted)
     }
 
+    // Run the optimize command on the Delta Table: merge small files into a large file by bin-packing.
+    #[pyo3(signature = (partition_filters = None, target_size = None))]
+    pub fn optimize(
+        &mut self,
+        partition_filters: Option<Vec<(&str, &str, PartitionFilterValue)>>,
+        target_size: Option<DeltaDataTypeLong>,
+    ) -> PyResult<String> {
+        let mut cmd = OptimizeBuilder::new(self._table.object_store(), self._table.state.clone());
+        if let Some(size) = target_size {
+            cmd = cmd.with_target_size(size);
+        }
+        let converted_filters = convert_partition_filters(partition_filters.unwrap_or_default())
+            .map_err(PyDeltaTableError::from_raw)?;
+        cmd = cmd.with_filters(&converted_filters);
+
+        let (table, metrics) = rt()?
+            .block_on(async { cmd.await })
+            .map_err(PyDeltaTableError::from_raw)?;
+        self._table.state = table.state;
+        Ok(serde_json::to_string(&metrics).unwrap())
+    }
+
     // Run the History command on the Delta Table: Returns provenance information, including the operation, user, and so on, for each write to a table.
     pub fn history(&mut self, limit: Option<usize>) -> PyResult<Vec<String>> {
         let history = rt()?

python/tests/test_optimize.py

@@ -0,0 +1,27 @@
+import pathlib
+
+import pyarrow as pa
+import pytest
+
+from deltalake import DeltaTable, write_deltalake
+
+
+@pytest.mark.parametrize("use_relative", [True, False])
+def test_optimize_run_table(
+    tmp_path: pathlib.Path, sample_data: pa.Table, monkeypatch, use_relative: bool
+):
+    if use_relative:
+        monkeypatch.chdir(tmp_path)  # Make tmp_path the working directory
+        (tmp_path / "path/to/table").mkdir(parents=True)
+        table_path = "./path/to/table"
+    else:
+        table_path = str(tmp_path)
+
+    write_deltalake(table_path, sample_data, mode="append")
+    write_deltalake(table_path, sample_data, mode="append")
+    write_deltalake(table_path, sample_data, mode="append")
+
+    dt = DeltaTable(table_path)
+    dt.optimize()
+    last_action = dt.history(1)[0]
+    assert last_action["operation"] == "OPTIMIZE"