Details
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Type:
Bug
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Status: Closed
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Priority:
Critical
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Resolution: Fixed
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Affects Version/s: 10.0.10
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Fix Version/s: 10.0.11
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Component/s: None
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Labels:None
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Environment:Windows 8, Windows Server 2012 R2, maybe others
Description
In 5.5.36, RLIKE and REGEXP work as they always have:
SELECT 'cat and dog' RLIKE 'cat.*dog'; => 1 In 10.0.10, SELECT 'cat and dog' RLIKE 'cat.*dog'; => 0
I consider this to be a critical issue that would cause queries to not function as expected.
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With PCRE, to have the dot to matchi a new line character, option (?s) should be set:
MariaDB [test]> SELECT 'cat and
dog' RLIKE '(?s)cat.*dog';
+--------------------------------------+
| 'cat and
dog' RLIKE '(?s)cat.*dog' |
+--------------------------------------+
| 1 |
+--------------------------------------+
1 row in set (0.00 sec)
See https://mariadb.com/kb/en/pcre-regular-expressions/#option-setting .
It's still not very good that the default behavior changed.
Maybe that option should be enabled by default, and using (?-s) would disable it.
On the other hand, it would be good to be as close to the "normal" pcre behavior as possible, users that know pcre shouldn't need to read mariadb manual to know all mariadb specific pcre quirks.
Alexander Barkov, perhaps we could add, like, @@default_regex_flags variable? This will keep pcre "normal behavior" in mariadb and won't change defaults post-GA, but users of old applications would be able to set 's' flag to be on by default.
That would be a good idea. I agree.
Added a new variable @@default_regex_flags.
To make "." match new line, one can add this command into my.cnf:
[mysqld]
default-regex-flags=DOTALL
See here for more details:
https://mariadb.com/kb/en/server-system-variables/#default_regex_flags
Pushed into 10.0.
Apparently the difference was caused by switching to PCRE.