Tiledb

Improvements

* Optimize `ResultTile::compute_results_sparse<char>` resulting in significant performance increases in certain cases with string dimensions [1963](https://github.com/TileDB-Inc/TileDB/pull/1963)

Improvements

* Optimized string dimension performance. [1922](https://github.com/TileDB-Inc/TileDB/pull/1922)

Bug fixes

* Updated the AWS SDK to v1.8.84 to fix an uncaught exception when using S3 [1899](https://github.com/TileDB-Inc/TileDB/pull/1899)[TileDB-Py #409](https://github.com/TileDB-Inc/TileDB-Py/issues/409)
* Fixed bug where a read on a sparse array may return duplicate values. [1905](https://github.com/TileDB-Inc/TileDB/pull/1905)
* Fixed bug where an array could not be opened if created with an array schema from an older version [1889](https://github.com/TileDB-Inc/TileDB/pull/1889)
* Fix compilation of TileDB Tools [1926](https://github.com/TileDB-Inc/TileDB/pull/1926)

Bug fixes

* Fix ArraySchema not write protecting fill values for only schema version 6 or newer [1868](https://github.com/TileDB-Inc/TileDB/pull/1868)
* Fix segfault that may occur in the VFS read-ahead cache [1871](https://github.com/TileDB-Inc/TileDB/pull/1871)

Bug fixes

* The result size estimatation routines will no longer return non-zero sizes that can not contain a single value. [1849](https://github.com/TileDB-Inc/TileDB/pull/1849)
* Fix serialization of dense writes that use ranges [1860](https://github.com/TileDB-Inc/TileDB/pull/1860)
* Fixed a crash from an unhandled SIGPIPE signal that may raise when using S3 [1856](https://github.com/TileDB-Inc/TileDB/pull/1856)

Breaking behavior

* Empty dense arrays now return cells with fill values. Also the result estimator is adjusted to work properly with this new behavior.

New features

* Added configuration option "sm.compute_concurrency_level" [1766](https://github.com/TileDB-Inc/TileDB/pull/1766)
* Added configuration option "sm.io_concurrency_level" [1766](https://github.com/TileDB-Inc/TileDB/pull/1766)
* Added configuration option "sm.sub_partitioner_memory_budget" [1729](https://github.com/TileDB-Inc/TileDB/pull/1729)
* Added configuration option "vfs.read_ahead_size" [1785](https://github.com/TileDB-Inc/TileDB/pull/1785)
* Added configuration option "vfs.read_ahead_cache_size" [1785](https://github.com/TileDB-Inc/TileDB/pull/1785)
* Added support for getting/setting Apache Arrow buffers from a Query [1816](https://github.com/TileDB-Inc/TileDB/pull/1816)

Improvements

* Source built curl only need HTTP support [1712](https://github.com/TileDB-Inc/TileDB/pull/1712)
* AWS SDK version bumped to 1.8.6 [1718](https://github.com/TileDB-Inc/TileDB/pull/1718)
* Split posix permissions into files and folers permissions [1719](https://github.com/TileDB-Inc/TileDB/pull/1719)
* Support seeking for CURL to allow redirects for posting to REST [1728](https://github.com/TileDB-Inc/TileDB/pull/1728)
* Changed default setting for `vfs.s3.proxy_scheme` from `https` to `http` to match common usage needs [1759](https://github.com/TileDB-Inc/TileDB/pull/1759)
* Enabled parallelization with native system threads when TBB is disabled [1760](https://github.com/TileDB-Inc/TileDB/pull/1760)
* Subarray ranges will be automatically coalesced as they are added [1755](https://github.com/TileDB-Inc/TileDB/pull/1755)
* Update GCS SDK to v1.16.0 to fixes multiple bugs reported [1768](https://github.com/TileDB-Inc/TileDB/pull/1768)
* Read-ahead cache for cloud-storage backends [1785](https://github.com/TileDB-Inc/TileDB/pull/1785)
* Allow multiple empty values at the end of a variable-length write [1805](https://github.com/TileDB-Inc/TileDB/pull/1805)
* Build system will raise overridable error if important paths contain regex character [1808](https://github.com/TileDB-Inc/TileDB/pull/1808)
* Lazily create AWS ClientConfiguration to avoid slow context creations for non S3 usage after the AWS SDK version bump [1821](https://github.com/TileDB-Inc/TileDB/pull/1821)
* Moved `Status`, `ThreadPool`, and `Logger` classes from folder `tiledb/sm` to `tiledb/common` [1843](https://github.com/TileDB-Inc/TileDB/pull/1843)

Deprecations

* Deprecated config option "sm.num_async_threads" [1766](https://github.com/TileDB-Inc/TileDB/pull/1766)
* Deprecated config option "sm.num_reader_threads" [1766](https://github.com/TileDB-Inc/TileDB/pull/1766)
* Deprecated config option "sm.num_writer_threads" [1766](https://github.com/TileDB-Inc/TileDB/pull/1766)
* Deprecated config option "vfs.num_threads" [1766](https://github.com/TileDB-Inc/TileDB/pull/1766)
* Support for MacOS older than 10.13 is being dropped when using the AWS SDK. Prebuilt Binaries now target 10.13 [1753](https://github.com/TileDB-Inc/TileDB/pull/1753)
* Use of Intel's Thread Building Blocks (TBB) will be discontinued in the future. It is now disabled by default [1762](https://github.com/TileDB-Inc/TileDB/pull/1762)
* No longer building release artifacts with Intel's Thread Building Blocks (TBB) enabled [1825](https://github.com/TileDB-Inc/TileDB/pull/1825)

Bug fixes

* Fixed bug in setting a fill value for var-sized attributes.
* Fixed a bug where the cpp headers would always produce compile-time warnings about using the deprecated c-api "tiledb_coords()" [1765](https://github.com/TileDB-Inc/TileDB/pull/1765)
* Only serialize the Array URI in the array schema client side. [1806](https://github.com/TileDB-Inc/TileDB/pull/1806)
* Fix C++ api `consolidate_metadata` function uses incorrect config [1841](https://github.com/TileDB-Inc/TileDB/pull/1841) [#1844](https://github.com/TileDB-Inc/TileDB/pull/1844)

API additions

C API

* Added functions `tiledb_attribute_{set,get}_fill_value` to get/set default fill values

C++ API

* Added functions `Attribute::{set,get}_fill_value` to get/set default fill values

Improvements

* Lazy initialization for GCS backend [1752](https://github.com/TileDB-Inc/TileDB/pull/1752)
* Add additional release artifacts which include disabling TBB [1753](https://github.com/TileDB-Inc/TileDB/pull/1753)

Bug fixes

* Fix crash during GCS backend initialization due to upstream bug. [1752](https://github.com/TileDB-Inc/TileDB/pull/1752)