E.3. Release Notes for Tantor SE 17.6.0#
E.3. Release Notes for Tantor SE 17.6.0 #
Release date: 2025-11-01
E.3.1. Review #
Tantor SE is a Russian-made DBMS based on the updated and improved version of the PostgreSQL DBMS. Tantor SE 17.6.0 is based on PostgreSQL 17.
Below are the additional modules and utilities added to Tantor SE, as well as a list of changes to the server core.
E.3.2. DBMS Core Functionality #
The following changes have been made to improve the DBMS:
Added optimization for queries with subquery disjunction (constructions like
WHERE EXISTS(...) OR EXISTS(...)) using the enable_or_expansion and or_expanded_other_disjuncts_cost_limit parameters. The planner now automatically converts them into a union of independent queries viaUNION ALLwith the elimination of duplicates, which makes it possible to apply index access for each condition separately instead of a full scan of the table.Added the enable_filter_predicates_reordering parameter, which allows to speed up the execution of queries with various scan types by optimizing the filter application order: the most selective conditions are checked first.
Added the default_statistics_target_temp_tables parameter to control the accuracy of temporary tables statistics, which, in combination with default_statistics_target, provides independent configuration of the level of detail in statistics for permanent and temporary tables.
Expanded parallel query execution support. Now, using the enable_parallel_insert parameter, parallelism is available when writing results into temporary tables, as well as in queries reading data from temporary tables in the
SELECTsection.Added the enable_pgstat_for_temp_rel parameter, which allows to disable the collection of statistics on temporary tables in the general
pg_stathash table. This solves the problem of LWLock locks and performance degradation with frequent operations with temporary tables, statistics on which are not critical for the operation of the system.Increased the invalidation message queue
MAXNUMMESSAGESlength from 16384 to 32768, which reduces the likelihood of buffer overflow and the need for complete cache invalidation under high loads with intensive creation of temporary tables.Fixed a memory leak for the hash table of unique query column names.
Fixed an error
could not create file ".../..._fsm": File existswith enabled enable_delayed_temp_file parameters.Improved the algorithm for calculating selectivity for fields used in
JOINconditions, so that increasing the value of the default_statistics_target parameter no longer increases overhead costs at the query planning stage.
E.3.3. Fixes for Additional Supplied Modules #
pg_tde — refinement and optimization of the extension. Added support for WAL encryption.
E.3.4. Migration to version 17.6.0 #
To migrate from PostgreSQL or Tantor DB, first install the latest minor version and then perform a data offload/restore by applying pg_dumpall, or use the pg_upgrade utility.