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new 910cc76f53 docs: document SessionConfig (#8771)
910cc76f53 is described below
commit 910cc76f53dc897708eaab45ed8ce09aac5bc8aa
Author: Will Jones <[email protected]>
AuthorDate: Thu Jan 11 13:07:42 2024 -0800
docs: document SessionConfig (#8771)
* docs: document SessionConfig
* make some tests happy
* pr feedback
---
datafusion/common/src/config.rs | 30 +++++-
datafusion/execution/src/config.rs | 103 ++++++++++++++++++---
.../sqllogictest/test_files/information_schema.slt | 2 +-
docs/source/user-guide/configs.md | 2 +-
4 files changed, 123 insertions(+), 14 deletions(-)
diff --git a/datafusion/common/src/config.rs b/datafusion/common/src/config.rs
index 9921c446f8..5c051a7dee 100644
--- a/datafusion/common/src/config.rs
+++ b/datafusion/common/src/config.rs
@@ -153,6 +153,10 @@ macro_rules! config_namespace {
config_namespace! {
/// Options related to catalog and directory scanning
+ ///
+ /// See also: [`SessionConfig`]
+ ///
+ /// [`SessionConfig`]:
https://docs.rs/datafusion/latest/datafusion/prelude/struct.SessionConfig.html
pub struct CatalogOptions {
/// Whether the default catalog and schema should be created
automatically.
pub create_default_catalog_and_schema: bool, default = true
@@ -180,6 +184,10 @@ config_namespace! {
config_namespace! {
/// Options related to SQL parser
+ ///
+ /// See also: [`SessionConfig`]
+ ///
+ /// [`SessionConfig`]:
https://docs.rs/datafusion/latest/datafusion/prelude/struct.SessionConfig.html
pub struct SqlParserOptions {
/// When set to true, SQL parser will parse float as decimal type
pub parse_float_as_decimal: bool, default = false
@@ -196,6 +204,10 @@ config_namespace! {
config_namespace! {
/// Options related to query execution
+ ///
+ /// See also: [`SessionConfig`]
+ ///
+ /// [`SessionConfig`]:
https://docs.rs/datafusion/latest/datafusion/prelude/struct.SessionConfig.html
pub struct ExecutionOptions {
/// Default batch size while creating new batches, it's especially
useful for
/// buffer-in-memory batches since creating tiny batches would result
in too much
@@ -283,6 +295,10 @@ config_namespace! {
config_namespace! {
/// Options related to parquet files
+ ///
+ /// See also: [`SessionConfig`]
+ ///
+ /// [`SessionConfig`]:
https://docs.rs/datafusion/latest/datafusion/prelude/struct.SessionConfig.html
pub struct ParquetOptions {
/// If true, reads the Parquet data page level metadata (the
/// Page Index), if present, to reduce the I/O and number of
@@ -306,7 +322,7 @@ config_namespace! {
pub metadata_size_hint: Option<usize>, default = None
/// If true, filter expressions are be applied during the parquet
decoding operation to
- /// reduce the number of rows decoded
+ /// reduce the number of rows decoded. This optimization is sometimes
called "late materialization".
pub pushdown_filters: bool, default = false
/// If true, filter expressions evaluated during the parquet decoding
operation
@@ -416,6 +432,10 @@ config_namespace! {
config_namespace! {
/// Options related to aggregate execution
+ ///
+ /// See also: [`SessionConfig`]
+ ///
+ /// [`SessionConfig`]:
https://docs.rs/datafusion/latest/datafusion/prelude/struct.SessionConfig.html
pub struct AggregateOptions {
/// Specifies the threshold for using `ScalarValue`s to update
/// accumulators during high-cardinality aggregations for each input
batch.
@@ -433,6 +453,10 @@ config_namespace! {
config_namespace! {
/// Options related to query optimization
+ ///
+ /// See also: [`SessionConfig`]
+ ///
+ /// [`SessionConfig`]:
https://docs.rs/datafusion/latest/datafusion/prelude/struct.SessionConfig.html
pub struct OptimizerOptions {
/// When set to true, the optimizer will push a limit operation into
/// grouped aggregations which have no aggregate expressions, as a
soft limit,
@@ -541,6 +565,10 @@ config_namespace! {
config_namespace! {
/// Options controlling explain output
+ ///
+ /// See also: [`SessionConfig`]
+ ///
+ /// [`SessionConfig`]:
https://docs.rs/datafusion/latest/datafusion/prelude/struct.SessionConfig.html
pub struct ExplainOptions {
/// When set to true, the explain statement will only print logical
plans
pub logical_plan_only: bool, default = false
diff --git a/datafusion/execution/src/config.rs
b/datafusion/execution/src/config.rs
index 8556335b39..5158e71773 100644
--- a/datafusion/execution/src/config.rs
+++ b/datafusion/execution/src/config.rs
@@ -24,7 +24,69 @@ use std::{
use datafusion_common::{config::ConfigOptions, Result, ScalarValue};
-/// Configuration options for Execution context
+/// Configuration options for [`SessionContext`].
+///
+/// Can be passed to [`SessionContext::new_with_config`] to customize the
configuration of DataFusion.
+///
+/// Options can be set using namespaces keys with `.` as the separator, where
the
+/// namespace determines which configuration struct the value to routed to. All
+/// built-in options are under the `datafusion` namespace.
+///
+/// For example, the key `datafusion.execution.batch_size` will set
[ExecutionOptions::batch_size][datafusion_common::config::ExecutionOptions::batch_size],
+/// because [ConfigOptions::execution] is
[ExecutionOptions][datafusion_common::config::ExecutionOptions]. Similarly, the
key
+/// `datafusion.execution.parquet.pushdown_filters` will set
[ParquetOptions::pushdown_filters][datafusion_common::config::ParquetOptions::pushdown_filters],
+/// since
[ExecutionOptions::parquet][datafusion_common::config::ExecutionOptions::parquet]
is [ParquetOptions][datafusion_common::config::ParquetOptions].
+///
+/// Some options have convenience methods. For example
[SessionConfig::with_batch_size] is
+/// shorthand for setting `datafusion.execution.batch_size`.
+///
+/// ```
+/// use datafusion_execution::config::SessionConfig;
+/// use datafusion_common::ScalarValue;
+///
+/// let config = SessionConfig::new()
+/// .set("datafusion.execution.batch_size", ScalarValue::UInt64(Some(1234)))
+/// .set_bool("datafusion.execution.parquet.pushdown_filters", true);
+///
+/// assert_eq!(config.batch_size(), 1234);
+/// assert_eq!(config.options().execution.batch_size, 1234);
+/// assert_eq!(config.options().execution.parquet.pushdown_filters, true);
+/// ```
+///
+/// You can also directly mutate the options via [SessionConfig::options_mut].
+/// So the following is equivalent to the above:
+///
+/// ```
+/// # use datafusion_execution::config::SessionConfig;
+/// # use datafusion_common::ScalarValue;
+/// #
+/// let mut config = SessionConfig::new();
+/// config.options_mut().execution.batch_size = 1234;
+/// config.options_mut().execution.parquet.pushdown_filters = true;
+/// #
+/// # assert_eq!(config.batch_size(), 1234);
+/// # assert_eq!(config.options().execution.batch_size, 1234);
+/// # assert_eq!(config.options().execution.parquet.pushdown_filters, true);
+/// ```
+///
+/// ## Built-in options
+///
+/// | Namespace | Config struct |
+/// | --------- | ------------- |
+/// | `datafusion.catalog` |
[CatalogOptions][datafusion_common::config::CatalogOptions] |
+/// | `datafusion.execution` |
[ExecutionOptions][datafusion_common::config::ExecutionOptions] |
+/// | `datafusion.execution.aggregate` |
[AggregateOptions][datafusion_common::config::AggregateOptions] |
+/// | `datafusion.execution.parquet` |
[ParquetOptions][datafusion_common::config::ParquetOptions] |
+/// | `datafusion.optimizer` |
[OptimizerOptions][datafusion_common::config::OptimizerOptions] |
+/// | `datafusion.sql_parser` |
[SqlParserOptions][datafusion_common::config::SqlParserOptions] |
+/// | `datafusion.explain` |
[ExplainOptions][datafusion_common::config::ExplainOptions] |
+///
+/// ## Custom configuration
+///
+/// Configuration options can be extended. See [SessionConfig::with_extension]
for details.
+///
+/// [`SessionContext`]:
https://docs.rs/datafusion/latest/datafusion/execution/context/struct.SessionContext.html
+/// [`SessionContext::new_with_config`]:
https://docs.rs/datafusion/latest/datafusion/execution/context/struct.SessionContext.html#method.new_with_config
#[derive(Clone, Debug)]
pub struct SessionConfig {
/// Configuration options
@@ -62,6 +124,35 @@ impl SessionConfig {
Ok(ConfigOptions::from_string_hash_map(settings)?.into())
}
+ /// Return a handle to the configuration options.
+ ///
+ /// Can be used to read the current configuration.
+ ///
+ /// ```
+ /// use datafusion_execution::config::SessionConfig;
+ ///
+ /// let config = SessionConfig::new();
+ /// assert!(config.options().execution.batch_size > 0);
+ /// ```
+ pub fn options(&self) -> &ConfigOptions {
+ &self.options
+ }
+
+ /// Return a mutable handle to the configuration options.
+ ///
+ /// Can be used to set configuration options.
+ ///
+ /// ```
+ /// use datafusion_execution::config::SessionConfig;
+ ///
+ /// let mut config = SessionConfig::new();
+ /// config.options_mut().execution.batch_size = 1024;
+ /// assert_eq!(config.options().execution.batch_size, 1024);
+ /// ```
+ pub fn options_mut(&mut self) -> &mut ConfigOptions {
+ &mut self.options
+ }
+
/// Set a configuration option
pub fn set(mut self, key: &str, value: ScalarValue) -> Self {
self.options.set(key, &value.to_string()).unwrap();
@@ -346,16 +437,6 @@ impl SessionConfig {
&mut self.options
}
- /// Return a handle to the configuration options.
- pub fn options(&self) -> &ConfigOptions {
- &self.options
- }
-
- /// Return a mutable handle to the configuration options.
- pub fn options_mut(&mut self) -> &mut ConfigOptions {
- &mut self.options
- }
-
/// Add extensions.
///
/// Extensions can be used to attach extra data to the session config --
e.g. tracing information or caches.
diff --git a/datafusion/sqllogictest/test_files/information_schema.slt
b/datafusion/sqllogictest/test_files/information_schema.slt
index 14ef290294..f8893bf7ae 100644
--- a/datafusion/sqllogictest/test_files/information_schema.slt
+++ b/datafusion/sqllogictest/test_files/information_schema.slt
@@ -248,7 +248,7 @@
datafusion.execution.parquet.maximum_buffered_record_batches_per_stream 2 By def
datafusion.execution.parquet.maximum_parallel_row_group_writers 1 By default
parallel parquet writer is tuned for minimum memory usage in a streaming
execution plan. You may see a performance benefit when writing large parquet
files by increasing maximum_parallel_row_group_writers and
maximum_buffered_record_batches_per_stream if your system has idle cores and
can tolerate additional memory usage. Boosting these values is likely
worthwhile when writing out already in-memory data, such as [...]
datafusion.execution.parquet.metadata_size_hint NULL If specified, the parquet
reader will try and fetch the last `size_hint` bytes of the parquet file
optimistically. If not specified, two reads are required: One read to fetch the
8-byte parquet footer and another to fetch the metadata length encoded in the
footer
datafusion.execution.parquet.pruning true If true, the parquet reader attempts
to skip entire row groups based on the predicate in the query and the metadata
(min/max values) stored in the parquet file
-datafusion.execution.parquet.pushdown_filters false If true, filter
expressions are be applied during the parquet decoding operation to reduce the
number of rows decoded
+datafusion.execution.parquet.pushdown_filters false If true, filter
expressions are be applied during the parquet decoding operation to reduce the
number of rows decoded. This optimization is sometimes called "late
materialization".
datafusion.execution.parquet.reorder_filters false If true, filter expressions
evaluated during the parquet decoding operation will be reordered heuristically
to minimize the cost of evaluation. If false, the filters are applied in the
same order as written in the query
datafusion.execution.parquet.skip_metadata true If true, the parquet reader
skip the optional embedded metadata that may be in the file Schema. This
setting can help avoid schema conflicts when querying multiple parquet files
with schemas containing compatible types but different metadata
datafusion.execution.parquet.statistics_enabled NULL Sets if statistics are
enabled for any column Valid values are: "none", "chunk", and "page" These
values are not case sensitive. If NULL, uses default parquet writer setting
diff --git a/docs/source/user-guide/configs.md
b/docs/source/user-guide/configs.md
index 4a379d374c..7111ea1d0a 100644
--- a/docs/source/user-guide/configs.md
+++ b/docs/source/user-guide/configs.md
@@ -53,7 +53,7 @@ Environment variables are read during `SessionConfig`
initialisation so they mus
| datafusion.execution.parquet.pruning |
true | If true, the parquet reader attempts to skip entire
row groups based on the predicate in the query and the metadata (min/max
values) stored in the parquet file
[...]
| datafusion.execution.parquet.skip_metadata |
true | If true, the parquet reader skip the optional
embedded metadata that may be in the file Schema. This setting can help avoid
schema conflicts when querying multiple parquet files with schemas containing
compatible types but different metadata
[...]
| datafusion.execution.parquet.metadata_size_hint |
NULL | If specified, the parquet reader will try and fetch
the last `size_hint` bytes of the parquet file optimistically. If not
specified, two reads are required: One read to fetch the 8-byte parquet footer
and another to fetch the metadata length encoded in the footer
[...]
-| datafusion.execution.parquet.pushdown_filters |
false | If true, filter expressions are be applied during
the parquet decoding operation to reduce the number of rows decoded
[...]
+| datafusion.execution.parquet.pushdown_filters |
false | If true, filter expressions are be applied during
the parquet decoding operation to reduce the number of rows decoded. This
optimization is sometimes called "late materialization".
[...]
| datafusion.execution.parquet.reorder_filters |
false | If true, filter expressions evaluated during the
parquet decoding operation will be reordered heuristically to minimize the cost
of evaluation. If false, the filters are applied in the same order as written
in the query
[...]
| datafusion.execution.parquet.data_pagesize_limit |
1048576 | Sets best effort maximum size of data page in bytes
[...]
| datafusion.execution.parquet.write_batch_size |
1024 | Sets write_batch_size in bytes
[...]
