Document why zlib is the only value for a compressed column

Signed-off-by: William Desportes <williamdes@wdes.fr>

1 files changed, 4 insertions, 0 deletions

diff --git a/libraries/classes/Util.php b/libraries/classes/Util.php
index 0d39ca8bae..2e5a88159b 100644
--- a/libraries/classes/Util.php
+++ b/libraries/classes/Util.php
@@ -1414,6 +1414,10 @@ class Util
         }
 
         if ($compressed) {
+            // With InnoDB page compression, multiple compression algorithms are supported.
+            // In contrast, with InnoDB's COMPRESSED row format, zlib is the only supported compression algorithm.
+            // This means that the COMPRESSED row format has less compression options than InnoDB page compression does.
+            // @see https://mariadb.com/kb/en/innodb-page-compression/#comparison-with-the-compressed-row-format
             $attribute = 'COMPRESSED=zlib';
         }