## Appendix E. Release Notes

The release notes contain the significant changes in each Postgres Pro Standard release, with major features and migration issues listed at the top. The release notes do not contain changes that affect only a few users or changes that are internal and therefore not user-visible. For example, the optimizer is improved in almost every release, but the improvements are usually observed by users as simply faster queries.

## E.1. Postgres Pro Standard 11.7.1

Release Date: 2020-02-27

### E.1.1. Overview

This release is based on PostgreSQL 11.7 and Postgres Pro Standard 11.6.1. All improvements inherited from PostgreSQL 11.7 are listed in PostgreSQL 11.7 Release Notes.

Major enhancements over Postgres Pro Standard 11.6.1 include:

- Added the enable_compound_index_stats configuration parameter to control the use of compound indexes statistics for selectivity estimation.

- Increased the maximum value of the track_activity_query_size parameter to 1MB. In vanilla PostgreSQL, this change is targeted for version 13.

- Improved query performance with row-level security policy enabled by correctly marking numeric comparison functions as leakproof.

- Fixed planner's optimization to correctly take into account similar `OR` clauses if they reference columns that are different, but have the same position in different indexes.

- Fixed self join removal functionality to achieve better stability.

- Optimized execution of queries with Materialize nodes that return nothing; now such nodes are called only once and skipped in all the subsequent runs.

- Fixed the `mchar` extension to correctly handle the `ESCAPE` clause in `SIMILAR TO` regular expressions.

- Upgraded pg_probackup to version 2.2.7.

- Upgraded mamonsu to version 2.4.4.

### E.1.2. Migration to Version 11.7.1

If you are upgrading from Postgres Pro Standard based on the same PostgreSQL major version, it is enough to install the new version into your current installation directory.

While functions `numeric_eq`, `numeric_ne`, `numeric_gt`, `numeric_ge`, `numeric_lt`, and `numeric_le` are actually leakproof, they were not marked as such in Postgres Pro Standard 11.6.1 or lower, which could lead to incorrect query optimization. In particular, it negatively affected query execution if row-level security policy was in use. Version 11.7.1 repairs this issue for new installations by correcting the initial catalog data, but existing installations will still have incorrect markings unless you update `pg_proc` entries for these functions. You can run pg_upgrade to upgrade your server instance to a version containing the corrected initial data, or manually correct these entries in each database of the installation using the `ALTER FUNCTION` command. For example:

    ALTER FUNCTION pg_catalog.numeric_eq VOLATILE

Version 11.7.1 also fixes `SIMILAR TO` and POSIX regular expressions that use character classes for icu collations, so you may need to check for objects that use such regular expressions.

Starting from Postgres Pro Standard 11.6.1, the ICU library upgrade does not interfere with the server start. Before connecting to a database using ICU as the default collation, Postgres Pro compares this collation version to the one provided by the ICU library and displays a warning if the collation versions do not match; you may need to rebuild the objects that depend on the default collation if you think the collation change may affect the sort order of your data. To suppress these warnings, you can use the `ALTER COLLATION "default" REFRESH VERSION` command, as explained in ALTER COLLATION.

Since pg_probackup delivery model changed in Postgres Pro Standard 11.2.1, when upgrading from a lower version on ALT Linux and Debian-based systems, run `apt dist-upgrade` (or `apt-get dist-upgrade`) to ensure that all new dependencies are handled correctly. On Windows, you have to run a separate pg_probackup installer to complete the upgrade.

To migrate from PostgreSQL or a Postgres Pro Standard release based on a previous PostgreSQL major version, see the migration instructions for version 11. If you are opting for a dump/restore, make sure to use the `--add-collprovider` option to correctly choose the provider for the default collation of the migrated database.