When searching for the user by a case-insensitive field (email address
is the only one supported now), the performance may be very poor as the
DB cannot use the index due to the LOWER() operation and the full
sequential scan of all the user records is performed. On some DBs such
as MySQL, this can be significantly improved by pre-filtering the users
with accent-insensitive search.
So we first perform accent-insensitive search for potential candidates
in a subselect, which can use the index. Only then we perform the
additional accent-sensitive search on this limited set or records.
When searching for other users with the same email address, we perform
the case-insensitive and accent-sensitive search. That may be expensive
as some DBs such as MySQL cannot use the index in that case. Instead,
sequential scan of all the user records is performed and the comparison
uses the LOWER function to filter the matching records. This leads to
significant performance heavy queries which in turn represent a surface
for DoS attacks.
For that reason, we first perform accent-insensitive search for
potential candidates in a subselect, which can use the index. Only then
we perform the additional accent-sensitive search on this limited set or
records.
When searching for the user matching the given email address, we perform
the case-insensitive and accent-sensitive search. That may be expensive
as some DBs such as MySQL cannot use the index in that case. Instead,
sequential scan of all the user records is performed and the comparison
uses the LOWER function to filter the matching records. This leads to
significant performance heavy queries which in turn represent a surface
for DoS attacks.
For that reason, we first perform accent-insensitive search for
potential candidates, which can use the index. Only then we perform the
additional accent-sensitive search on this limited set or records.
This commit makes several changes:
1) Explicitly stop polling for messages when a conversation is deleted;
2) Check for deleted conversations when displaying new messages;
3) Do not add a new empty conversation; and
4) Introduce pendingJS checks to ensure that Behat waits for messags to finish rendering.
A new plugintype has been created for having more than one installed
third-party H5P libraries. Existing libraries have been moved from
lib/h5p to the new h5plib_v124 plugin.
Component names should always support numbers (but the first character).
This patch will add PARAM_COMPONENT the expected regular expression
to validate the expected format.
.accesshide was removed because:
1. It was only kept in case it's still used somewhere, in a custom form
field for instance.
2. It was broken since 3.5 where we integrated
https://github.com/bmbrands/moodle/compare/ab65b87f3d...MDL-62419-master
So it's been ages that the reason mentioned on point 1 was not being
satisfied
