Important Since version 2.2 we use a different algorithm for tracking changed pages. Thus, data recorded in the ptrack.map using pre 2.2 versions of ptrack is incompatible with newer versions. After extension upgrade and server restart old ptrack.map will be discarded with WARNING and initialized from the scratch.

• ptrack now uses two slots to record page change information. It
  helps significantly reduce number of false positives with the same
  ptrack.map_size. See #5 for details. Many thanks to @funny-falcon for
  ideas, theory and review!
• ptrack_get_pagemapset() now also displays a number of changed blocks
  per file.
• Added ptrack_get_change_stat(start_lsn pg_lsn) that can desplay statistic
  of changes (number of files, pages and size in MB) since specified start_lsn.

• Fix int32 overflow when doing a ptrack checkpoint with
  ptrack.map_size > 16 GB.
• Adjust ptrack checkpoint buffer for a ~20% better performance.

• PostgreSQL 11 and 13 support. Thanks to @alubennikova.
• Fixed an int32 overflow issue, when one was unable to set
  ptrack.map_size to 2 GB and above. New limit is 32 GB.

Both ptrack engine and public SQL API are now inside extension. Only
certain required hooks have been left as a PostgreSQL core patch.

Also many things have changed since 2.0.0:

• Fixed many compatibility bugs: alignment issues with atomics usage on Win32,
  with atomics simulation via spinlocks.
• Added versioning into the ptrack map.
• Added automated standalone testing with pg_probackup via travis-ci in
  different modes, including a ‘legacy’ mode, i.e. with EXEC_BACKEND
  and --disable-atomics.
• Removed pg_ptrack_get_block.

Upgrading from 2.0.0:

• Put shared_preload_libraries = 'ptrack' into postgresql.conf.
• Rename ptrack_map_size to ptrack.map_size.
• Do ALTER EXTENSION 'ptrack' UPDATE;.
• Restart server.

Ptrack is a fast block-level incremental backup engine for PostgreSQL.
Currently ptrack codebase is split approximately 50%/50% between
PostgreSQL core patch and extension. All public SQL API methods are
placed in the ptrack extension, while the main engine is still in core.

Credits to:

• Konstantin Knizhnik
• Anastasia Lubennikova
• Alexey Kondratov