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Dave Gosselin 9cc99091a7 MDEV-39014: FULL JOIN Phase 2

In phase 1, FULL [OUTER] JOIN was only supported when simplify_joins()
could rewrite it into an equivalent LEFT, RIGHT, or INNER JOIN based
on NULL-rejecting WHERE predicates.  Queries that could not be
rewritten raised ER_NOT_SUPPORTED_YET.  (Phase 1 was not released.)

This commit removes that restriction by adding proper support for FULL
JOIN by executing a 'LEFT JOIN pass' that emits matched rows and left
null-complemented rows, then a second "null-complement" pass which
rescans the right table to emit null-complement rows that were never
matched.

FULL JOIN supports nested joins on the left of the FULL JOIN,
NATURAL FULL JOIN, semi-joins, CTEs / derived tables (kept
materialized when they participate in a FULL JOIN), prepared
statements, stored procedures, and aggregates.  Examples:

  SELECT * FROM (d1 FULL JOIN d2 ON d1.a = d2.a)
              FULL JOIN t3 ON d1.a = t3.a;

  SELECT * FROM t1 NATURAL FULL JOIN t2;

  SELECT * FROM t1 INNER JOIN t2 FULL JOIN t3 ON t1.a = t3.a;

  PREPARE st FROM
    'SELECT COUNT(*) FROM t1 FULL JOIN t2 ON t1.a = t2.a';

Limitations:
  - Statistics and cost estimates for the null-complement pass have
    not been fully implemented; the optimizer may under- or
    over-estimate FULL JOIN costs in plans involving multiple
    FULL JOINs.  Again, a follow-up will optimize the cost calculations.
  - Optimizations for constant tables not fully supported.
  - Nested tables on the right side of a FULL JOIN are not yet supported.

2026-09-01 10:25:47 -04:00

charsets

Merge 11.8 into 12.3

2026-04-02 09:15:17 +03:00

CMakeLists.txt

…

errmsg-utf8.txt

MDEV-39014: FULL JOIN Phase 2

2026-09-01 10:25:47 -04:00

insert_translations_into_errmsg.py

…

README.md

Fix remaining typos

2025-04-29 11:18:00 +10:00

README.md

A quicker way for adding new language translations to the errmsg-utf8.txt file

Summary

To generate a new language translation of MariaDB use the following pull request (PR) as a template for your work:

https://github.com/MariaDB/server/pull/2676

You will notice as part of your translation work, you will have to add your language translations to the file sql/share/errmsg-utf8.txt which is found in the current directory. This file is long with many sections which can make the translation work tedious. In this README, we explain a procedure and provide a script insert_translations_into_errmsg.py that cuts down the amount of tedium in accomplishing the task.

Procedure

Start by grepping out all the english translations from errmsg-utf8.txt using the following grep command, and redirecting the output to a file:

grep -P "^\s*eng\s" errmsg-utf8.txt > all_english_text_in_errmsg-utf8.txt
Next use Google translate to obtain a translation of this file. Google translate provides the ability to upload whole files for translation. For example, this technique was used to obtain Swahili translations which yielded a file with output similar to the below (output is truncated for clarity):

sw "hashchk" sw "isamchk" sw "LA" sw "NDIYO" sw "Haiwezi kuunda faili '% -.200s' (kosa: %iE)" sw "Haiwezi kuunda jedwali %s.%s (kosa: %iE)" sw "Haiwezi kuunda hifadhidata '% -.192s' (kosa: %iE)" sw "Haiwezi kuunda hifadhidata '% -.192s'; hifadhidata ipo"

Note that Google translate removes the leading whitespace in the translation file it generates. DO NOT add that leading whitespace back!

Give the translated file an appropriate name (e.g. all_swahili_text_in_errmsg-utf8.txt) and store it in the same directory with errmsg-utf8.txt and all_english_text_in_errmsg-utf8.txt. These 3 files will be used by the script insert_translations_into_errmsg.py.
Proof check the auto-translations in the file you downloaded from Google translate. Note that Google might omit formatting information that will cause the compilation of MariaDB to fail, so pay attention to these.
Reintegrate these translations into the errmsg-utf8.txt by running the insert_translations_into_errmsg.py script as follows:

chmod ugo+x insert_translations_into_errmsg.py # Make the script executable if it is not.

./insert_translations_into_errmsg.py <errmsg-utf8.txt file>

For example, for the swahili translation, we ran the following:

./insert_translations_into_errmsg.py errmsg-utf8.txt all_english_text_in_errmsg-utf8.txt all_swahili_text_in_errmsg-utf8.txt

The script uses the errmsg-utf8.txt file and the grepped english file to keep track of each new translation. It then creates a file in the same directory as errmsg-utf8.txt with the name errmsg-utf8-with-new-language.txt.
Check that the reintegration of the new translations into errmsg-utf8-with-new-language.txt went OK, and if it did, rename errmsg-utf8-with-new-language.txt to errmsg-utf8.txt:

mv errmsg-utf8-with-new-language.txt errmsg-utf8.txt
In the header of errmsg-utf8.txt make sure to add your language long form to short form mapping. E.g. for Swahili, add:

swahili=sw