libmdbx 0.12.1 (Positive Proxima)

The planned frontward release with new superior features on the day of 20 anniversary of Positive Technologies.

37 files changed, 7604 insertions(+), 7417 deletions(-)
Signed-off-by: Леонид Юрьев (Leonid Yuriev) <leo@yuriev.ru>

New:

• The Big Foot feature which significantly reduces GC overhead for processing large lists of retired pages from huge transactions. Now libmdbx avoid creating large chunks of PNLs (page number lists) which required a long sequences of free pages, aka large/overflow pages. Thus avoiding searching, allocating and storing such sequences inside GC.
• Improved hot/online validation and checking of database pages both for more robustness and performance.
• New solid and fast method to latch meta-pages called Troika. The minimum of memory barriers, reads, comparisons and conditional transitions are used.
• New MDBX_VALIDATION environment options to extra validation of DB structure and pages content for carefully/safe handling damaged or untrusted DB.
• Accelerated ×16/×8/×4 by AVX512/AVX2/SSE2/Neon implementations of search page sequences.
• Added the gcrtime_seconds16dot16 counter to the “Page Operation Statistics” that accumulates time spent for GC searching and reclaiming.
• Copy-with-compactification now clears/zeroes unused gaps inside database pages.
• The C and C++ APIs has been extended and/or refined to simplify using wchar_t pathnames. On Windows the mdbx_env_openW(), mdbx_env_get_pathW(), mdbx_env_copyW(), mdbx_env_open_for_recoveryW() are available for now, but the mdbx_env_get_path() has been replaced in favor of mdbx_env_get_pathW().
• Added explicit error message for Buildroot’s Microblaze toolchain maintainers.
• Added MDBX_MANAGE_BUILD_FLAGS build options for CMake.
• Speed-up internal bsearch/lower_bound implementation using branchless tactic, including workaround for CLANG x86 optimiser bug.
• A lot internal refinement and micro-optimisations.
• Internally counted volume of dirty pages (unused for now but for coming features).

Fixes:

• Never use modern __cxa_thread_atexit() on Apple’s OSes.
• Don’t check owner for finished transactions.
• Fixed typo in MDBX_EINVAL which breaks MingGW builds with CLANG.

Downloads:

• 254K, libmdbx-amalgamated-0.12.1.zpaq, sha256sum: 5a5f5a4f024bb9e752a6f0ed3ae1e7b51372dbedfd77e0f989993e87c67a2136
• 340K, libmdbx-amalgamated-0.12.1.tar.xz, sha256sum: d498f2ebbfd96952fbf7ac21a965d42f6a980d1f4f3cf7aeae8580d54855b651
• 448K, libmdbx-amalgamated-0.12.1.tar.bz2, sha256sum: 1a15f2d764957a2776215246cedce732de5ccf51726b4b63413bd8aedd5f38e0
• 692K, libmdbx-amalgamated-0.12.1.tar.gz, sha256sum: 43039f27387cdedc442e8f79908f8b67101a1b4fbba32d7c14c4e217ee483320
• 704K, libmdbx-amalgamated-0_12_1.zip, sha256sum: aea687db7f6de1db4bdd9c24d76b2740d9345740a930d2bb0eb25c328d89bed0

For earlier versions please refer to the git tags and the ChangeLog.