Python Polars 0.20.22

🚀 Performance improvements

• Improved type-inference for read_excel and read_ods, use calamine engine for read_ods (#15808)
• Fix quadratic in binview growable same source (#15734)
• use two binary searches for equality mask when data is sorted (#15702)
• improve filter parallelism (#15686)

✨ Enhancements

• Minor type-inference update for read_database (#15809)
• Improved type-inference for read_excel and read_ods, use calamine engine for read_ods (#15808)
• dt.truncate supports broadcasting lhs (#15768)
• Expressify str.json_path_match (#15764)
• raise if storage_options is passed to read_csv but fsspec isnt available (#15778)
• Support decimal float parsing in CSV (#15774)
• Add context trace to LazyFrame conversion errors (#15761)
• Improve error message when passing invalid input to lit (#15718)
• Remove outdated join validation checks (#15701)

🐞 Bug fixes

• drop-nulls edge case; remove drop-nulls special case (#15815)
• ewm_mean_by was skipping initial nulls when it was already sorted by "by" column (#15812)
• Consult cgroups to determine free memory (#15798)
• raise if index count like 2i is used when performing rolling, group_by_dynamic, upsample, or other temporal operatios (#15751)
• Don't deduplicate sort that has slice pushdown (#15784)
• Allow passing files opened by fsspec in read_parquet (#15770)
• Fix incorrect is_between pushdown to scan_pyarrow_dataset (#15769)
• Handle null index correctly for list take (#15737)
• Preserve lexical ordering on concat (#15753)
• Remove incorrect unsafe pointer cast for int -> enum (#15740)
• pass series name to apply for cut/qcut (#15715)
• count of null column shouldn't panic in agg context (#15710)
• manual cache (#15711)
• Ensure we don't hold onto Mutex when grabbing join tuples (#15704)
• allow null dtypes in UDFs if they match the schema (#15699)
• Respect join_null argument for semi/anti joins (#15696)
• Ensure we don't hold RwLock when spawning group parallelism in w… (#15697)
• Ensure empty with_columns is a no-op (#15694)
• Include predicate in cache state union (#15693)
• Add the missing feature flag for ewm_mean_by (#15687)
• 8/16-bits int could also apply in place for log expr (#15680)
• prepare_expression_for_context shouldn't panic if exceptions raised from optimizer (#15681)

📖 Documentation

• Add docstring examples for datetimes (#13161) (#15804)
• Fix a typo in categorical section of the user guide (#15777)
• Fix a docstring mistake for DataType.is_float (#15773)
• Remove incorrect "1i (1 index count)" from some docs methods (#15750)
• Add example for Config.set_tbl_width_chars (#15566)
• Align docstring phrasing in Series/Expr.dt.truncate/round (#15698)
• Various deprecation docstring improvements (#15648)

🛠️ Other improvements

• Always expand horizontal_any/all (#15816)
• Rename decimal_float to decimal_comma (#15817)
• Split coverage calculation (#15780)
• Update readme (#15787)
• Start at using new Bound<> API from PyO3 (#15752)
• Make json_path_match expr non-anonymous (#15682)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @NedJWestern, @Robinsane, @TobiasDummschat, @alexander-beedie, @c-peters, @dependabot, @dependabot[bot], @gasmith, @henryharbeck, @itamarst, @kszlim, @mbuhidar, @nameexhaustion, @orlp, @reswqa, @ritchie46, @stinodego and @wsyxbcl

Rust Polars 0.39.2

🚀 Performance improvements

• use two binary searches for equality mask when data is sorted (#15702)
• improve filter parallelism (#15686)

✨ Enhancements

• Remove outdated join validation checks (#15701)

🐞 Bug fixes

• manual cache (#15711)
• Ensure we don't hold onto Mutex when grabbing join tuples (#15704)
• allow null dtypes in UDFs if they match the schema (#15699)
• Respect join_null argument for semi/anti joins (#15696)
• Ensure we don't hold RwLock when spawning group parallelism in w… (#15697)
• Ensure empty with_columns is a no-op (#15694)
• Include predicate in cache state union (#15693)
• Add the missing feature flag for ewm_mean_by (#15687)
• 8/16-bits int could also apply in place for log expr (#15680)
• prepare_expression_for_context shouldn't panic if exceptions raised from optimizer (#15681)

🛠️ Other improvements

• Make json_path_match expr non-anonymous (#15682)

Thank you to all our contributors for making this release possible!
@henryharbeck, @kszlim, @orlp, @reswqa and @ritchie46

Python Polars 0.20.22-rc.1

🚀 Performance improvements

• improve filter parallelism (#15686)

🐞 Bug fixes

• Add the missing feature flag for ewm_mean_by (#15687)
• 8/16-bits int could also apply in place for log expr (#15680)
• prepare_expression_for_context shouldn't panic if exceptions raised from optimizer (#15681)

📖 Documentation

• Various deprecation docstring improvements (#15648)

🛠️ Other improvements

• Make json_path_match expr non-anonymous (#15682)

Thank you to all our contributors for making this release possible!
@henryharbeck, @reswqa and @ritchie46

Rust Polars 0.39.1

🚀 Performance improvements

• Fix regression that led to using only a single thread (#15667)

✨ Enhancements

• add ewm_mean_by (#15638)

🐞 Bug fixes

• Ensure profile of simple-projection only take own runtime (#15671)
• Panic if invalid array in object (#15664)
• Ensure 'CachedSchema' doesn't get synced between plans (#15661)
• group_by multiple null columns produce phantom row (#15659)
• rolling_* aggs were behaving as if they return scalars in group-by (#15657)
• Correct the unsoundness slice range of arr.min/max (#15654)
• list.mean fast path shouldn't produce NaN (#15652)
• Fix Display implementation of Duration (#15647)

📖 Documentation

• Fix typo in legacy install instructions (#15662)
• Include prelude import in the example (#15633)

🛠️ Other improvements

• Remove the remaining usage of deprecated numpy crate APIs (#15668)
• make Duration.is_constant_duration less strict for non-timezone-aware case (#15639)
• Fix some typos in comments (#15665)
• remove unnecessary unsafe in list mean/sum (#15660)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @Priyansh4444, @StevenMia, @itamarst, @mcrumiller, @orlp, @reswqa, @ritchie46 and @stinodego

Python Polars 0.20.21

🚀 Performance improvements

• Fix regression that led to using only a single thread (#15667)

✨ Enhancements

• add ewm_mean_by (#15638)

🐞 Bug fixes

• Ensure profile of simple-projection only take own runtime (#15671)
• Panic if invalid array in object (#15664)
• Ensure 'CachedSchema' doesn't get synced between plans (#15661)
• group_by multiple null columns produce phantom row (#15659)
• rolling_* aggs were behaving as if they return scalars in group-by (#15657)
• Correct the unsoundness slice range of arr.min/max (#15654)
• list.mean fast path shouldn't produce NaN (#15652)

📖 Documentation

• Add missing deprecation warning to DataFrame.replace (#15612)
• Fix typo in legacy install instructions (#15662)

🛠️ Other improvements

• make Duration.is_constant_duration less strict for non-timezone-aware case (#15639)
• Fix some typos in comments (#15665)
• remove unnecessary unsafe in list mean/sum (#15660)
• fixup failing test due to offset deprecation in upsample (#15636)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @Priyansh4444, @StevenMia, @eitsupi, @itamarst, @mcrumiller, @orlp, @reswqa, @ritchie46 and @stinodego

Rust Polars 0.39.0

🏆 Highlights

• Full plan CSE (#15264)

💥 Breaking changes

• rename memmap -> memory_map as like Python (#15642)
• pref(rust!, python): Unify sort with SortOptions and SortMultipleOptions (#15590)
• Update the argument name from dims to dimensions in reshape (#15561)
• Allow specifying Hive schema in read/scan_parquet (#15434)
• Raise error when schema_overrides contains nonexistent column name (#15290)
• Rename Chunk to RecordBatch (#15298)
• Refactor AnyValue supertype logic (#15280)
• Rename group_by_rolling to rolling and improve related error messages (#14765)
• Rename ChunkedArray.try_apply to try_apply_values (#14947)
• Rename parameter by to group_by in DataFrame.upsample/group_by_dynamic/rolling (#14840)

🚀 Performance improvements

• Fix cross join batch size when one of the DataFrames is tiny (#14347)
• Fix binview growable complexity O(n*m) -> O(n) (#15628)
• Remove extra thread spawn from row group fetcher (#15626)
• Use vertical parallelism if input is chunked for Filter,Select,WithColumns (#15608)
• read_ipc memory usage tests, and writing fix (#15599)
• Refactor CSV serialization to not go thorough AnyValue (#15576)
• don't use dynamic dispatch in visitors (#15607)
• Improve Bitmap construction performance (#15570)
• join by row-encoding (#15559)
• Replace std::thread spawn with tokio block_in_place (#15517)
• speed up offset_by when a single offset is passed (#15493)
• Avoid allocation in the hot path for struct JSON serialization (#15449)
• avoid double-allocation in rolling_apply_agg_window (#15423)
• Make LogicalPlan immutable (#15416)
• Add non-order preserving variable row-encoding (#15414)
• Use row-encoding for multiple key group by (#15392)
• load bits one word at a time for BitmapIter (#15333)
• Ipc exec multiple paths (#15040)
• add SIMD support for if-then-else kernels (#15131)

✨ Enhancements

• add Expr.dt.add_business_days and Series.dt.add_business_days (#15595)
• Add str.head and str.tail (#14425)
• Extended BytecodeParser to handle additional math functions, and imports from the global namespace (#15627)
• Push down is_between expressions to Arrow (#15180)
• add holidays argument to business_day_count (#15580)
• change default to write parquet statistics (#15597)
• Expressify to_integer (#15604)
• Optimizer; remove double SORT and redundant projections (#15573)
• Add null_on_oob parameter to expr.array.get (#15426)
• support weekend argument in business_day_count (#15544)
• Enable is_first/last_distinct for not nested non-numeric list (#15552)
• Turn off cse if cache node found (#15554)
• Tag concat list as elementwise (#15545)
• Support list group-by of non numeric lists (#15540)
• add business_day_count function (#15512)
• Add SQL support for MEDIAN aggfunc (#15519)
• Implement string, boolean and binary dtype in top_k (#15488)
• Add SQL support for TRUNCATE TABLE command (#15513)
• Add SQL support for GREATEST and LEAST (#15511)
• Allow specifying Hive schema in read/scan_parquet (#15434)
• Implements agg_list for NullChunked (#15439)
• Supports explode_by_offsets for decimal (#15417)
• Add null_on_oob parameter to expr.list.get (#15395)
• CSV-writer escape carriage return (#15399)
• Remove 'FileCacher' optimization (#15357)
• check input type in entropy (#15351)
• Implements arr.n_unique (#15296)
• CSE don't scan share if predicate pushdown predicates don't match (#15328)
• Remove cached nodes when finished (#15310)
• Full plan CSE (#15264)
• Add IR for expressions. (#15168)
• Warn if map_elements is called without return_dtype specified (#15188)
• Rename group_by_rolling to rolling and improve related error messages (#14765)
• Rename ChunkedArray.try_apply to try_apply_values (#14947)
• Implement strict AnyValue construction for temporal types (#15146)

🐞 Bug fixes

• Return appropriate data type for time mean and median (#14471)
• Support index upsampling (#13621)
• Fix issue in write_excel that could lead to incorrect spanning range determination (#15631)
• Output correct dtype for mean_horizontal on a single column (#15118)
• Recompute RowIndex schema after projection pd (#15625)
• Mean of boolean in streaming group_by incorrectly always gave NULL (#15616)
• Include cloud creds in cache key (#15609)
• Fix elementwise-apply if any input is AggregatedScalar (#15606)
• Explode list should take validity into account (#15572)
• use larger recursive stack in debug mode (#15593)
• SQL interface "off-by-one' indexing error with GROUP BY clauses that use position ordinals (#15584)
• Enable missing features in polars-time (#15558)
• Handle quoted identifiers when registering CTEs in the SQL engine (#15564)
• Decompress moved out of schema initialization (#15550)
• Turn off cse if cache node found (#15554)
• Resolve function names and prune all aliases. (#15522)
• list.get should take validity into account (#15516)
• block decimal in streaming (#15520)
• group_by partitioned with literal Series panic (#15487)
• Initialize validity for GroupsProxy::Slice windows (#15509)
• Fix struct name resolving (#15507)
• pow return type evaluation (#15506)
• Allow selectors inside frame-level .filter() (#15445)
• Don't prune alias in AnonymousFunction subtree (#15453)
• Fix deadlock in async parquet scan (#15440)
• datetime operations (e.g. .dt.year) were raising when null values were backed by out-of-range integers (#15420)
• Ensure Binary -> Binview cast doesn't overflow the buffer size (#15408)
• Don't prune alias in function subtree (#15406)
• Return 0 for n_unique() in group-by context when group is empty (#15289)
• Unset UpdateGroups after group-sensitive expression (#15400)
• to_any_value should supports all LiteralValue type (#15387)
• Hash failure combining hash of two numeric columns containing equal values (#15397)
• Add FixedSizeBinary to arrow field conversion (#15389)
• Conversion of expr_ir in partition fast path (#15388)
• sort for series with unsupported dtype should raise instead of panic (#15385)
• Return correct dtype for s.clear() when dtype is Object (#15315)
• ensure first datapoint is always included in group_by_dynamic (#15312)
• Non-exhaustive patterns: arrow-schema::DataType in polars-arrow (#15250)
• use dynamic stacks for problematic recursive functions (#15355)
• Raise error when schema_overrides contains nonexistent column name (#15290)
• Fix cache dot visualization (#15311)
• Properly propagate strict flag when constructing a Struct Series from any values (#15302)
• ensure eq for BinaryViewArray checks all elements (#15268)
• Raise when join projects name with suffix that doesn't exist (#15256)
• fix kurtosis/skew (#15137)
• Ensure ooc_start is set (#15255)
• Fix bug where rolling operations were ignoring check_sorted in some cases (#15227)
• Fix lazy schema for rle expression (#15248)
• incorrect negative offset in multi-byte string slicing (#15140)
• do not clamp negative offsets to start of array prematurely (#15242)
• allow null index in list.get and array.get (#15239)
• properly support nulls_last + descending (#15212)
• Block rounding/truncating to negative durations (#15175)
• Make parse_url work on windows with object_store (#15191)
• divide by zero in download speed computation (#15182)

📖 Documentation

• Add legacy CPU install instructions in user guide (#13676)
• Various minor updates to User Guide's SQL intro section (#15557)
• Add outer_coalesce join strategy in the user guide (#15405)
• Improve docs for Series::new with AnyValue input (#15306)
• Fix formatting in Series::from_any_values_and_dtype docs (#15244)
• Correct the definition of an expression in the user guide (#14750)

📦 Build system

• Fix a feature gate for lz4 compression in polars-parquet (#15565)
• Update Rust toolchain (#15353)

🛠️ Other improvements

• rename memmap -> memory_map as like Python (#15642)
• fixup failing test due to offset deprecation in upsample (#15636)
• use bound api (#15630)
• Don't run streaming group-by in partitionable gb (#15611)
• pref(rust!, python): Unify sort with SortOptions and SortMultipleOptions (#15590)
• remove try_binary_elementwise_values (#15592)
• remove raw pointers from visitors. (#15579)
• rename to IR (#15571)
• Update the argument name from dims to dimensions in reshape (#15561)
• Rename ALogicalPlan to FullAccessIR (#15553)
• Set up CodSpeed (#15537)
• make dsl immutable and cheap to clone (#15394)
• use recursive crate, add missing recursive tag (#15393)
• Update CODEOWNERS (polars-sql) (#15384)
• Update Rust toolchain (#15353)
• Update CODEOWNERS (#15352)
• remove try_apply_values (#15336)
• always use non-legacy float_sum for mean (#15343)
• remove legacy bitmap module (#15335)
• More clippy in Makefile (#15340)
• Rename Cache[count] to Cache[cache_hits] (#15300)
• Cleanup file_caching optimization call (#15299)
• Rename Chunk to RecordBatch (#15298)
• Refactor AnyValue supertype logic (#15280)
• reuse message parsing in IPC (#15265)
• remove 'fast-projection' node (#15253)
• cleanup column names in optimizer (#15252)
• remove left_most_input_name from expr ir (#15251)
• add AlignedBitmapSlice (#15171)
• Refactor AnyValue construction for Categorical/Enum dtype (#15220)
• Move ConsecutiveCountState into support module (#15186)
• Run non-benchmark tests in benchmark workflow (#15207)
• Add wrapping_abs to arithmetic kernel (#15210)
• remove raw buffers from BinViewArray (#15206)
• Enable RUST_BACKTRACE=1 in the CI test suite (#15204)
• Rename parameter by to group_by in DataFrame.upsample/group_by_dynamic/rolling (#14840)
• Set dual license for polars-arrow and polars-parquet (#15173)
  ...

Python Polars 0.20.20

🚀 Performance improvements

• Fix cross join batch size when one of the DataFrames is tiny (#14347)
• Fix binview growable complexity O(n*m) -> O(n) (#15628)
• Remove extra thread spawn from row group fetcher (#15626)
• Use vertical parallelism if input is chunked for Filter,Select,WithColumns (#15608)
• Refactor CSV serialization to not go thorough AnyValue (#15576)
• don't use dynamic dispatch in visitors (#15607)
• Improve Bitmap construction performance (#15570)
• join by row-encoding (#15559)

✨ Enhancements

• add Expr.dt.add_business_days and Series.dt.add_business_days (#15595)
• Add str.head and str.tail (#14425)
• Add union/or operator for pl.Enum (#14965)
• Extended BytecodeParser to handle additional math functions, and imports from the global namespace (#15627)
• Push down is_between expressions to Arrow (#15180)
• add holidays argument to business_day_count (#15580)
• change default to write parquet statistics (#15597)
• Expressify to_integer (#15604)
• Optimizer; remove double SORT and redundant projections (#15573)
• Add null_on_oob parameter to expr.array.get (#15426)
• support weekend argument in business_day_count (#15544)
• Enable is_first/last_distinct for not nested non-numeric list (#15552)
• Turn off cse if cache node found (#15554)
• Tag concat list as elementwise (#15545)

🐞 Bug fixes

• Return appropriate data type for time mean and median (#14471)
• Fix issue in write_excel that could lead to incorrect spanning range determination (#15631)
• Output correct dtype for mean_horizontal on a single column (#15118)
• Recompute RowIndex schema after projection pd (#15625)
• Mean of boolean in streaming group_by incorrectly always gave NULL (#15616)
• Include cloud creds in cache key (#15609)
• Fix elementwise-apply if any input is AggregatedScalar (#15606)
• Explode list should take validity into account (#15572)
• use larger recursive stack in debug mode (#15593)
• SQL interface "off-by-one' indexing error with GROUP BY clauses that use position ordinals (#15584)
• Enable missing features in polars-time (#15558)
• Handle quoted identifiers when registering CTEs in the SQL engine (#15564)
• Decompress moved out of schema initialization (#15550)
• Turn off cse if cache node found (#15554)

📖 Documentation

• Add legacy CPU install instructions in user guide (#13676)
• Examples for errors (#13724)
• Add docstring examples for reading json (#14481)
• Add security warning in LazyFrame.deserialize() docstring (#15282)
• Various minor updates to User Guide's SQL intro section (#15557)

🛠️ Other improvements

• Replace most deprecated calls with bounded version (#15632)
• use bound api (#15630)
• Initial PyO3 0.21 support (#15622)
• Don't run streaming group-by in partitionable gb (#15611)
• pref(rust!, python): Unify sort with SortOptions and SortMultipleOptions (#15590)
• Set up CodSpeed (#15537)

Thank you to all our contributors for making this release possible!
@CanglongCl, @ChayimFriedman2, @Fokko, @JamesCE2001, @MarcoGorelli, @NedJWestern, @TrevorWinstral, @alexander-beedie, @deanm0000, @douglas-raillard-arm, @eitsupi, @filabrazilska, @i-aki-y, @itamarst, @leoforney, @mcrumiller, @nameexhaustion, @orlp, @ozgrakkurt, @reswqa, @ritchie46 and @stinodego

Python Polars 0.20.19

🚀 Performance improvements

• Replace std::thread spawn with tokio block_in_place (#15517)
• speed up offset_by when a single offset is passed (#15493)
• Avoid allocation in the hot path for struct JSON serialization (#15449)

✨ Enhancements

• Support list group-by of non numeric lists (#15540)
• add business_day_count function (#15512)
• Add SQL support for MEDIAN aggfunc (#15519)
• Implement string, boolean and binary dtype in top_k (#15488)
• Add SQL support for TRUNCATE TABLE command (#15513)
• Add SQL support for GREATEST and LEAST (#15511)
• Allow specifying Hive schema in read/scan_parquet (#15434)
• Implements agg_list for NullChunked (#15439)

🐞 Bug fixes

• dot product of two integer series is cast to float (#15502)
• Resolve function names and prune all aliases. (#15522)
• Pass skip_rows_after_header to pyarrow csv reader (#15533)
• No longer error when schema_overrides contains nonexistent columns (#15528)
• list.get should take validity into account (#15516)
• block decimal in streaming (#15520)
• group_by partitioned with literal Series panic (#15487)
• Initialize validity for GroupsProxy::Slice windows (#15509)
• Fix struct name resolving (#15507)
• pow return type evaluation (#15506)
• Address issue with read_database draining iter_batches early (#15504)
• Allow selectors inside frame-level .filter() (#15445)
• Don't prune alias in AnonymousFunction subtree (#15453)
• Raise if pass a negative n into clear (#15432)
• Fix deadlock in async parquet scan (#15440)

📖 Documentation

• Update leftover references of by parameter to group_by in DataFrame/LazyFrame.upsample/group_by_dynamic/rolling (#15527)
• Add make docs command, DataType docs/layout tweak, minor README updates (#15386)
• Add example for Series.list.median. (#15451)

🛠️ Other improvements

• Remove unused code paths in read_parquet (#15532)
• Organize utils for I/O functionality (#15529)
• Remove private DataFrame._read classmethods (#15521)
• Move dedicated inference code out of io.database executor module (#15526)
• Add unstable warning to hive_schema functionality (#15508)

Thank you to all our contributors for making this release possible!
@CanglongCl, @ChayimFriedman2, @MarcoGorelli, @alexander-beedie, @cmdlineluser, @dependabot, @dependabot[bot], @henryharbeck, @mbuhidar, @nameexhaustion, @reswqa, @ritchie46, @rob-sil and @stinodego

Python Polars 0.20.18

🚀 Performance improvements

• CSV reading memory usage tests and fixes (#15422)
• avoid double-allocation in rolling_apply_agg_window (#15423)
• Make LogicalPlan immutable (#15416)
• Add non-order preserving variable row-encoding (#15414)
• Use row-encoding for multiple key group by (#15392)

✨ Enhancements

• Supports explode_by_offsets for decimal (#15417)
• Add read_clipboard and DataFrame.write_clipboard (#15272)
• Add null_on_oob parameter to expr.list.get (#15395)
• make Series.__bool__ error message Rusttier (#15407)
• CSV-writer escape carriage return (#15399)

🐞 Bug fixes

• datetime operations (e.g. .dt.year) were raising when null values were backed by out-of-range integers (#15420)
• Ensure Binary -> Binview cast doesn't overflow the buffer size (#15408)
• Don't prune alias in function subtree (#15406)
• Return 0 for n_unique() in group-by context when group is empty (#15289)
• Unset UpdateGroups after group-sensitive expression (#15400)
• to_any_value should supports all LiteralValue type (#15387)
• Hash failure combining hash of two numeric columns containing equal values (#15397)
• Add FixedSizeBinary to arrow field conversion (#15389)
• Conversion of expr_ir in partition fast path (#15388)
• fix panic when doing a scan_parquet with hive partioning (#15381)
• sort for series with unsupported dtype should raise instead of panic (#15385)

📖 Documentation

• Added example for explode mapping strategy in pl.Expr.over (#15402)
• Add outer_coalesce join strategy in the user guide (#15405)
• Change the example to series for series/array.py (#15383)
• Add "See Also" for arg_sort and arg_sort_by (#15348)

🛠️ Other improvements

• make dsl immutable and cheap to clone (#15394)
• use recursive crate, add missing recursive tag (#15393)
• Update CODEOWNERS (polars-sql) (#15384)

Thank you to all our contributors for making this release possible!
@CanglongCl, @JamesCE2001, @MarcoGorelli, @Sol-Hee, @alexander-beedie, @dependabot, @dependabot[bot], @itamarst, @kszlim, @mcrumiller, @nameexhaustion, @orlp, @reswqa, @ritchie46, @rob-sil and @thomaslin2020

Python Polars 0.20.17

🏆 Highlights

• Full plan CSE (#15264)

⚠️ Deprecations

• Rename parameter by to group_by in DataFrame.upsample/group_by_dynamic/rolling (#14840)
• Rename from_repr parameter from tbl to data (#15156)

🚀 Performance improvements

• load bits one word at a time for BitmapIter (#15333)
• Ipc exec multiple paths (#15040)
• add SIMD support for if-then-else kernels (#15131)

✨ Enhancements

• Remove 'FileCacher' optimization (#15357)
• check input type in entropy (#15351)
• Implements arr.n_unique (#15296)
• CSE don't scan share if predicate pushdown predicates don't match (#15328)
• Add read_database support for SurrealDB ("ws" and "http") (#15269)
• Only allow inputs of type Sequence in from_records (#15329)
• In hypothesis testing strategies, enable Decimal strategy by default (#15321)
• Remove cached nodes when finished (#15310)
• Full plan CSE (#15264)
• More robust handling of async database calls (#15202)
• Add name parameter to GroupBy.len method (#15235)
• Add IR for expressions. (#15168)
• Improve read_database when reading from Kùzu graph database (#15218)
• Warn if map_elements is called without return_dtype specified (#15188)
• Add support for async SQLAlchemy connections to read_database (#15162)
• Infer time_unit in pl.duration when nanoseconds is specified (#14987)
• Add strict parameter to from_dict/from_records (#15158)

🐞 Bug fixes

• Return correct dtype for s.clear() when dtype is Object (#15315)
• ensure first datapoint is always included in group_by_dynamic (#15312)
• Non-exhaustive patterns: arrow-schema::DataType in polars-arrow (#15250)
• use dynamic stacks for problematic recursive functions (#15355)
• Adding default ddof for Series.list.std and Series.list.var (#15267)
• Raise properly for slices not supported by LazyFrame (#15331)
• Propagate strictness in from_dicts (#15344)
• Raise error when schema_overrides contains nonexistent column name (#15290)
• Enforce integer dtype input for int_range and int_ranges (#15339)
• Preserve Decimal precision when constructing empty Series (#15320)
• Fix cache dot visualization (#15311)
• Handle special case correctly when slicing a LazyFrame (#15297)
• Properly propagate strict flag when constructing a Struct Series from any values (#15302)
• Consistent expansion of nested struct data during DataFrame init from dict (#15217)
• Raise when join projects name with suffix that doesn't exist (#15256)
• Ensure ooc_start is set (#15255)
• Fix bug where rolling operations were ignoring check_sorted in some cases (#15227)
• Fix lazy schema for rle expression (#15248)
• incorrect negative offset in multi-byte string slicing (#15140)
• do not clamp negative offsets to start of array prematurely (#15242)
• allow null index in list.get and array.get (#15239)
• Avoid loading all columns in read_parquet when columns parameter is specified (#15229)
• properly support nulls_last + descending (#15212)
• fix nested runtime panic (#15216)
• Block rounding/truncating to negative durations (#15175)
• Ensure the cs.temporal() selector uses wildcard time zone matching for Datetime (#13683)
• Consistently raise TypeError on constructor failure (#15178)
• Properly propagate strictness in some constructor cases (#15166)
• Fix constructing a Series from a list of Series with given dtype (#15144)

📖 Documentation

• Fix time unit in timestamp example (#15281)
• Fix link to renamed method (.list.lengths -> .list.len) (#15228)
• Update Excel and database pages in user guide (#14721)
• Add examples for Series.search_sorted (#14737)
• Correct the definition of an expression in the user guide (#14750)
• Add a note about the behaviour of lower/upper bounds for is_between, and add an example (#15197)

📦 Build system

• Update Cargo lock (#15370)

🛠️ Other improvements

• Memory usage test infrastructure, plus a test for #15098 (#15285)
• Update CODEOWNERS (#15352)
• remove try_apply_values (#15336)
• always use non-legacy float_sum for mean (#15343)
• remove legacy bitmap module (#15335)
• Fix test not writing to temporary directory (#15318)
• Reorganize tests for clear operation (#15304)
• Rename Cache[count] to Cache[cache_hits] (#15300)
• Cleanup file_caching optimization call (#15299)
• Minor refactor of PyDataFrame.from_dicts (#15274)
• remove 'fast-projection' node (#15253)
• cleanup column names in optimizer (#15252)
• remove left_most_input_name from expr ir (#15251)
• add AlignedBitmapSlice (#15171)
• Run non-benchmark tests in benchmark workflow (#15207)
• Add wrapping_abs to arithmetic kernel (#15210)
• remove raw buffers from BinViewArray (#15206)
• Enable RUST_BACKTRACE=1 in the CI test suite (#15204)
• Split read_database functionality into cleaner module structure (#15201)
• Clean up some of the AnyValue conversion logic (#15190)
• remove parts of legacy bit_util (#15169)
• remove legacy arrow compute (#15164)
• Split up dataframe module in PyO3 bindings (#15165)
• Remove unused private constructors (#15160)

Thank you to all our contributors for making this release possible!
@MarcoGorelli, @alexander-beedie, @braaannigan, @c-peters, @cojmeister, @deanm0000, @dependabot, @dependabot[bot], @itamarst, @kszlim, @mbuhidar, @mcrumiller, @mickvangelderen, @orlp, @petrosbar, @reswqa, @ritchie46, @rob-sil, @sportfloh, @stinodego and @yutannihilation