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@leborchuk leborchuk commented Sep 19, 2025

We inherited this issue from PostgreSQL.

PostgreSQL uses glibc to sort strings. In version glibc=2.28, collations broke down badly (in general, there are no guarantees when updating glibc). Changing collations breaks indexes. Similarly, a cluster with different collations also behaves unpredictably.

What and when something has changed in glibc can be found on https://github.com/ardentperf/glibc-unicode-sorting Also there is special postgresql-wiki https://wiki.postgresql.org/wiki/Locale_data_changes And you tube video https://www.youtube.com/watch?v=0E6O-V8Jato

In short, the issue can be seen through the use of bash:

( echo "1-1"; echo "11" ) | LC_COLLATE=en_US.UTF-8 sort

gives the different results in ubuntu 18.04 and 22.04.

There is no way to solve the problem other than by not changing the symbol order. We freeze symbol order and use it instead of glibc.

Here the solution https://github.com/postgredients/mdb-locales.

In this PR I have added PostgreSQL patch that replaces all glibc locale-related calls with a calls to an external libary. It activates using new configure parameter --with-mdblocales, which is off by default.

Using custom locales needs libmdblocales1 package and mdb-locales package with symbol table.

Build needs libmdblocales-dev package with headers.

Fixing the symbol order is necessary for OS upgrade. For example Ubuntu 22.04 EOL is April 2027, Rocky 8 Active Support ended May 2024, and Security support ends in 2029.

We use Movable DataBase Locales in Greenplum 6 and all our PostgreSQL installations (starting with PostgreSQL 12). This patch is adopted patch version from our internal PostgreSQL 14 fork.

usernamedt and others added 2 commits September 19, 2025 11:56
We inherited this issue from PostgreSQL.

PostgreSQL uses glibc to sort strings. In version glibc=2.28, collations
broke down badly (in general, there are no guarantees when updating glibc).
Changing collations breaks indexes. Similarly, a cluster with different
collations also behaves unpredictably.

What and when something has changed in glibc can be found
on https://github.com/ardentperf/glibc-unicode-sorting
Also there is special postgresql-wiki https://wiki.postgresql.org/wiki/Locale_data_changes
And you tube video https://www.youtube.com/watch?v=0E6O-V8Jato

In short, the issue can be seen through the use of bash:

( echo "1-1"; echo "11" ) | LC_COLLATE=en_US.UTF-8 sort

gives the different results in ubunru 18.04 and 22.04.

There is no way to solve the problem other than by not changing the symbol order.
We freeze symbol order and use it instead of glibc.

Here the solution https://github.com/postgredients/mdb-locales.

In this PR I have added PostgreSQL patch that replaces all glibc
locale-related calls with a calls to an external libary. It activates
using new configure parameter --with-mdblocales, which is off by
default.

Using custom locales needs libmdblocales1 package and mdb-locales
package with symbol table.

Build needs libmdblocales-dev package with headers.
@jianlirong
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jianlirong commented Sep 19, 2025 via email

* MDB admin patch & tests

This patch introcudes new pseudo-pre-defined role "mdb_admin".

Introduces 2 new function:
extern bool mdb_admin_allow_bypass_owner_checks(Oid userId,  Oid ownerId);
extern void check_mdb_admin_is_member_of_role(Oid member, Oid role);

To check mdb admin belongship and role-to-role ownership transfer
correctness.

Our mdb_admin ACL model is the following:

* Any roles user or/and roles can be granted with mdb_admin
* mdb_admin memeber can tranfser ownershup of relations,
namespaces and functions to other roles, if target role in neither:
superuser, pg_read_server_files, pg_write_server_files nor
pg_execute_server_program.

This patch allows mdb admin to tranfers ownership on non-superuser objects

* f
@my-ship-it my-ship-it requested a review from yjhjstz September 22, 2025 02:30
reshke and others added 2 commits September 30, 2025 12:43
This commit introduces new mdb internal role mdb_superuser.

Role is capaple of:

GRANT/REVOKE any set of priviledges to/from any object in database.
Has power of pg_database_owner in any database, including:
DROP any object in database (except system catalog and stuff)

Role is NOT capaple of:

Create database, role, extension or alter other roles with such
priviledges.

Transfer ownership to /pass has_priv of roles:

PG_READ_ALL_DATA
PG_WRITE_ALL_DATA
PG_EXECUTE_SERVER_PROGRAM
PG_READ_SERVER_FILES
PG_WRITE_SERVER_FILES
PG_DATABASE_OWNER

Fix configure.ac USE_MDBLOCALES option handling

Apply autoreconf stuff

Set missing ok parameter ito true while acquiring mdb_superuser oid

In regress tests, nobody creates mdb_superuser role, so missing ok is
fine

Allow mdb_superuser to have power of pg_database_owner

Allow mdb_superuser to alter objects and grant ACl to
objects, owner by pg_database_owner. Also, when acl check,
allow mdb_supersuer use pg_database_owner role power to pass check
@leborchuk leborchuk marked this pull request as draft October 1, 2025 09:16
@leborchuk leborchuk force-pushed the AddMDBLocale branch 2 times, most recently from b358d88 to 2510f35 Compare October 6, 2025 08:53
@leborchuk leborchuk marked this pull request as ready for review October 6, 2025 12:49
@leborchuk
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Fixed all the issues, failed tests still waiting for the working CI

We inherited this issue from PostgreSQL.

PostgreSQL uses glibc to sort strings. In version glibc=2.28, collations
broke down badly (in general, there are no guarantees when updating glibc).
Changing collations breaks indexes. Similarly, a cluster with different
collations also behaves unpredictably.

What and when something has changed in glibc can be found
on https://github.com/ardentperf/glibc-unicode-sorting
Also there is special postgresql-wiki https://wiki.postgresql.org/wiki/Locale_data_changes
And you tube video https://www.youtube.com/watch?v=0E6O-V8Jato

In short, the issue can be seen through the use of bash:

( echo "1-1"; echo "11" ) | LC_COLLATE=en_US.UTF-8 sort

gives the different results in ubunru 18.04 and 22.04.

There is no way to solve the problem other than by not changing the symbol order.
We freeze symbol order and use it instead of glibc.

Here the solution https://github.com/postgredients/mdb-locales.

In this PR I have added PostgreSQL patch that replaces all glibc
locale-related calls with a calls to an external libary. It activates
using new configure parameter --with-mdblocales, which is off by
default.

Using custom locales needs libmdblocales1 package and mdb-locales
package with symbol table.

Build needs libmdblocales-dev package with headers.
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5 participants