Moodle in English: Help, I can't read messages dmlreadexception

Please some idea about could be the problem?. When i try to read some messages i get a "dmlreadexception"

debugging info for this message is:

File: /lib/dml/moodle_database.php

Line: 486

SQL server has gone away

SELECT mdl_context.id AS ctxid, mdl_context.path AS ctxpath, mdl_context.depth AS ctxdepth, mdl_context.contextlevel AS ctxlevel, mdl_context.instanceid AS ctxinstance, mdl_context.locked AS ctxlocked FROM mdl_context WHERE id IN (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)

-- line 1500 of /lib/dml/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()

-- line 663 of /message/classes/api.php: call to context_helper::preload_contexts_by_id()

-- line 1348 of /message/externallib.php: call to core_message\api::get_conversations()

-- line 261 of /lib/externallib.php: call to core_message_external::get_conversations()

-- line 81 of /lib/ajax/service.php: call to external_api::call_external_function()

[array (

0 => NULL,

1 => NULL,

2 => NULL,

3 => NULL,

4 => NULL,

5 => NULL,

6 => NULL,

7 => NULL,

8 => NULL,

9 => NULL,

10 => NULL,

11 => NULL,

12 => NULL,

13 => NULL,

14 => NULL,

15 => NULL,

16 => NULL,

17 => NULL,

18 => NULL,

19 => NULL,

20 => NULL,

21 => NULL,

22 => NULL,

)]

Error code: dmlreadexception

* line 486 of /lib/dml/moodle_database.php: dml_read_exception thrown

* line 1273 of /lib/dml/mysqli_native_moodle_database.php: call to moodle_database->query_end()

* line 1500 of /lib/dml/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()

* line 6123 of /lib/accesslib.php: call to moodle_database->get_records_select()

* line 663 of /message/classes/api.php: call to context_helper::preload_contexts_by_id()

* line 1348 of /message/externallib.php: call to core_message\api::get_conversations()

* line 261 of /lib/externallib.php: call to core_message_external::get_conversations()

* line 81 of /lib/ajax/service.php: call to external_api::call_external_function()

Variables in the database are:

+--------------------+---------+

| Variable_name      | Value   |
+--------------------+---------+
| max_allowed_packet | 67108864|
| net_read_timeout   | 30      |
| net_write_timeout  | 60      |
| wait_timeout       | 28800   |
+--------------------+---------+

Moodle configuration

Server checks

Name	Information	Report	Status
moodle		version 3.5 is required and you are running 3.10 (Build: 20201109)	OK
unicode		must be installed and enabled	OK
database	mysql (8.0.15)	version 5.7 is required and you are running 8.0.15	OK
php		version 7.2.0 is required and you are running 7.3.26	OK
pcreunicode		should be installed and enabled for best results	OK
php_extension	iconv	must be installed and enabled	OK
php_extension	mbstring	must be installed and enabled	OK
php_extension	curl	must be installed and enabled	OK
php_extension	openssl	must be installed and enabled	OK
php_extension	tokenizer	should be installed and enabled for best results	OK
php_extension	xmlrpc	should be installed and enabled for best results	OK
php_extension	soap	should be installed and enabled for best results	OK
php_extension	ctype	must be installed and enabled	OK
php_extension	zip	must be installed and enabled	OK
php_extension	zlib	must be installed and enabled	OK
php_extension	gd	must be installed and enabled	OK
php_extension	simplexml	must be installed and enabled	OK
php_extension	spl	must be installed and enabled	OK
php_extension	pcre	must be installed and enabled	OK
php_extension	dom	must be installed and enabled	OK
php_extension	xml	must be installed and enabled	OK
php_extension	xmlreader	must be installed and enabled	OK
php_extension	intl	must be installed and enabled	OK
php_extension	json	must be installed and enabled	OK
php_extension	hash	must be installed and enabled	OK
php_extension	fileinfo	must be installed and enabled	OK
php_setting	memory_limit	recommended setting detected	OK
php_setting	file_uploads	recommended setting detected	OK
php_setting	opcache.enable	recommended setting detected	OK

Other checks

Information	Report	Plugin	Status
mysql_full_unicode_support	if this test fails, it indicates a potential problem The current setup of MySQL or MariaDB is using 'utf8'. This character set does not support four byte characters which include some emoji. Trying to use these characters will result in an error when updating a record, and any information being sent to the database will be lost. Please consider changing your settings to 'utf8mb4'. See the documentation for full details.

Average of ratings: -

Re: Help, I can't read messages dmlreadexception

by Ken Task - Friday, 23 April 2021, 2:41 AM

'server has gone away' in past has generally meant max_allowed_packets value/setting needs to be increased. See it's 67.x Meg ... try bumping it up just a little to 70 or 75 M .... then try it again.

Also probably wouldn't hurt (for future upgrades) to address/fix the full compliance issue ... InnoDB, Barracuda, utf8mb4 character set with utf8mb4_unicode_ci, etc.

https://docs.moodle.org/310/en/MySQL_full_unicode_support

'SoS', Ken

Average of ratings: -

Re: Help, I can't read messages dmlreadexception

by carlos sandoval - Friday, 21 May 2021, 3:45 AM

Thank you for your orientation, I updated max_allowed_packet up to 104857600, but error still present.

Looking in to browser´s console i can see that error is localed in xhr post

http://localhost/moodle311/lib/ajax/service.php?sesskey=EYZO3y1REB&info=core_message_get_conversations
with the request payload:

[{"index":0,"methodname":"core_message_get_conversations","args":{"userid":"2","type":1,"limitnum":51,"limitfrom":0,"favourites":false,"mergeself":true}}]

wich response json response is :

[{"error":true,"exception":{"message":"Error al leer de la base de datos","errorcode":"dmlreadexception","backtrace":"* line 486 of \/lib\/dml\/moodle_database.php: dml_read_exception thrown\n* line 1273 of \/lib\/dml\/mysqli_native_moodle_database.php: call to moodle_database->query_end()\n* line 1500 of \/lib\/dml\/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()\n* line 6130 of \/lib\/accesslib.php: call to moodle_database->get_records_select()\n* line 669 of \/message\/classes\/api.php: call to context_helper::preload_contexts_by_id()\n* line 1362 of \/message\/externallib.php: call to core_message\\api::get_conversations()\n* line 261 of \/lib\/externallib.php: call to core_message_external::get_conversations()\n* line 81 of \/lib\/ajax\/service.php: call to external_api::call_external_function()\n","link":"http:\/\/elearning.cepal.org\/moodle\/test\/moodle311\/","moreinfourl":"https:\/\/docs.moodle.org\/311\/es\/error\/moodle\/dmlreadexception","debuginfo":"MySQL server has gone away\nSELECT mdltest_context.id AS ctxid, mdltest_context.path AS ctxpath, mdltest_context.depth AS ctxdepth, mdltest_context.contextlevel AS ctxlevel, mdltest_context.instanceid AS ctxinstance, mdltest_context.locked AS ctxlocked FROM mdltest_context WHERE id IN (?,?) \n-- line 1500 of \/lib\/dml\/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()\n-- line 669 of \/message\/classes\/api.php: call to context_helper::preload_contexts_by_id()\n-- line 1362 of \/message\/externallib.php: call to core_message\\api::get_conversations()\n-- line 261 of \/lib\/externallib.php: call to core_message_external::get_conversations()\n-- line 81 of \/lib\/ajax\/service.php: call to external_api::call_external_function()\n[array (\n 0 => NULL,\n 1 => NULL,\n)]\nError code: dmlreadexception"}}]

Average of ratings: -

Re: Help, I can't read messages dmlreadexception

by carlos sandoval - Monday, 31 May 2021, 11:22 PM

I updated max_allowed_packet up to 104857600, but error still present. Looking in to browser´s console i can see that error is localed in xhr post

http://XXXXXX/moodle311/lib/ajax/service.php?sesskey=EYZO3y1REB&info=core_message_get_conversations
with the request payload:

[\{"index":0,"methodname":"core_message_get_conversations","args":{"userid":"2","type":1,"limitnum":51,"limitfrom":0,"favourites":false,"mergeself":true}}]

wich response json response is :

[{"error":true,"exception":{"message":"Error al leer de la base de datos","errorcode":"dmlreadexception","backtrace":"* line 486 of \/lib\/dml\/moodle_database.php: dml_read_exception thrown\n* line 1273 of \/lib\/dml\/mysqli_native_moodle_database.php: call to moodle_database->query_end()\n* line 1500 of \/lib\/dml\/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()\n* line 6130 of \/lib\/accesslib.php: call to moodle_database->get_records_select()\n* line 669 of \/message\/classes\/api.php: call to context_helper::preload_contexts_by_id()\n* line 1362 of \/message\/externallib.php: call to core_message\\api::get_conversations()\n* line 261 of \/lib\/externallib.php: call to core_message_external::get_conversations()\n* line 81 of \/lib\/ajax\/service.php: call to external_api::call_external_function()\n","link":"http:\/\/xxxxxxxxxx\/moodle\/test\/moodle311\/","moreinfourl":"https:\/\/docs.moodle.org\/311\/es\/error\/moodle\/dmlreadexception","debuginfo":"MySQL server has gone away\nSELECT mdltest_context.id AS ctxid, mdltest_context.path AS ctxpath, mdltest_context.depth AS ctxdepth, mdltest_context.contextlevel AS ctxlevel, mdltest_context.instanceid AS ctxinstance, mdltest_context.locked AS ctxlocked FROM mdltest_context WHERE id IN (?,?) \n-- line 1500 of \/lib\/dml\/moodle_database.php: call to mysqli_native_moodle_database->get_records_sql()\n-- line 669 of \/message\/classes\/api.php: call to context_helper::preload_contexts_by_id()\n-- line 1362 of \/message\/externallib.php: call to core_message\\api::get_conversations()\n-- line 261 of \/lib\/externallib.php: call to core_message_external::get_conversations()\n-- line 81 of \/lib\/ajax\/service.php: call to external_api::call_external_function()\n[array (\n 0 => NULL,\n 1 => NULL,\n)]\nError code: dmlreadexception"}}]

Average of ratings: -

Re: Help, I can't read messages dmlreadexception

by Ken Task - Tuesday, 1 June 2021, 1:21 AM

Even after increasing to suggested (which was a guess), it says:

MySQL server has gone away

updated max_allowed_packet up to 104857600
which is about 100MB. Did you restart the DB service?

Normally, one also sees in web service error logs 'tried to allocate x bytes' (more). Does it show that? It should also show how much it tried to allocate 'byes more'.

Increase value by that many + a little more.

So, one more guess ... 110MB.

If your server is Linux and you can install software, suggest you install MySQL Tuner ... a perl script that will check DB stats and make recommendations for tweaks to my.cnf (config) for DB server.

'SoS', Ken

Average of ratings: -

Re: Help, I can't read messages dmlreadexception

by Leon Stringer - Tuesday, 1 June 2021, 2:11 AM

This appears to be the same issue as this forum post which is logged as MDL-69604.

Average of ratings: -

Re: Help, I can't read messages dmlreadexception

by Leon Stringer - Tuesday, 1 June 2021, 2:18 AM

Also Carlos: If you are running Moodle 3.10 (Build: 20201109) then your site is six months behind on bug fixes including 19 security fixes. You should update to 3.10.4.

Average of ratings: -

General help

Help, I can't read messages dmlreadexception

Help, I can't read messages dmlreadexception

Server checks

Other checks

Re: Help, I can't read messages dmlreadexception

Re: Help, I can't read messages dmlreadexception

Re: Help, I can't read messages dmlreadexception

Re: Help, I can't read messages dmlreadexception

Re: Help, I can't read messages dmlreadexception

Re: Help, I can't read messages dmlreadexception

Empowering educators to improve our world

Moodle

Support

Get Involved

Contributions

Downloads

Tracker

Development

Empowering educators to improve our world