mysqli errors on many pages

digamcrown

Hello dear forum

Unfortunately, I can't find any information in the search that could help me with my error. After updating to the latest version, error messages are very common. First, the browser reports that there is an error in a module. This is displayed below the page. It always says the same thing there:

Type: E_USER_ERROR (256) Message: mysqli error: [1451: Cannot delete or update a parent row: a foreign key constraint fails (usr_web606_5.session_client, CONSTRAINTsession_client_ibfk_1FOREIGN KEY (session_name) REFERENCESsession(name`))] in EXECUTE("DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'")

File: /var/www/web606/html/epesi/libs/adodb/adodb-errorhandler.inc.php
Line=79
error backtrace:
[PHP core called function]
function called: handle_epesi_error(256, "mysqli error: [1451: Cannot delete or update a parent row: a foreign key constraint fails (usr_web606_5.session_client, CONSTRAINT session_client_ibfk_1 FOREIGN KEY (session_name) REFERENCES session (name))] in EXECUTE(\"DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'\")
", "/var/www/web606/html/epesi/libs/adodb/adodb-errorhandler.inc.php", 79, Array ("mysqli", "EXECUTE", 1451, "Cannot delete or update a parent row: a foreign key constraint fails (usr_web606_5.session_client, CONSTRAINT session_client_ibfk_1 FOREIGN KEY (session_name) REFERENCES session (name))", "DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'", false, Object (ADODB_mysqli), "DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'", false, "mysqli error: [1451: Cannot delete or update a parent row: a foreign key constraint fails (usr_web606_5.session_client, CONSTRAINT session_client_ibfk_1 FOREIGN KEY (session_name) REFERENCES session (name))] in EXECUTE(\"DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'\")
"))

File: /var/www/web606/html/epesi/libs/adodb/adodb-errorhandler.inc.php
line 79
function called: trigger_error("mysqli error: [1451: Cannot delete or update a parent row: a foreign key constraint fails (usr_web606_5.session_client, CONSTRAINT session_client_ibfk_1 FOREIGN KEY (session_name) REFERENCES session (name))] in EXECUTE(\"DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'\")
", 256)

File: /var/www/web606/html/epesi/libs/adodb/adodb.inc.php
line 1235
function called: ADODB_Error_Handler("mysqli", "EXECUTE", 1451, "Cannot delete or update a parent row: a foreign key constraint fails (usr_web606_5.session_client, CONSTRAINT session_client_ibfk_1 FOREIGN KEY (session_name) REFERENCES session (name))", "DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'", false, Object (ADODB_mysqli))

File: /var/www/web606/html/epesi/libs/adodb/adodb.inc.php
line 1175
function called: _Execute("DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'")

File: /var/www/web606/html/epesi/include/database.php
line 213
function called: Execute("DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'", Array (Array (#1)))

File: /var/www/web606/html/epesi/include/database.php
line 378
function called: call_with_retry("Execute", Array ("DELETE FROM session WHERE name=?", Array (#1)))

File: /var/www/web606/html/epesi/include/session.php
line 334
function called: Execute("DELETE FROM session WHERE name=%s", Array ("c7ee89899cf536e7a195ba2bcc072be2"))

File: /var/www/web606/html/epesi/include/session.php
line 154
function called: clear("c7ee89899cf536e7a195ba2bcc072be2")

File: /var/www/web606/html/epesi/include/session.php
line 168
function called: destroy("c7ee89899cf536e7a195ba2bcc072be2")

[PHP core called function]
function called: gc(1440)

File: /var/www/web606/html/epesi/include/session.php
line 491
function called: session_start()

File: /var/www/web606/html/epesi/include.php
line 35
function called: require_once("/var/www/web606/html/epesi/include/session.php")

File: /var/www/web606/html/epesi/process.php
line 21
function called: require_once("/var/www/web606/html/epesi/include.php")`

Does anyone happen to know why this is, or how I can correct this error?

Thanks in advance

jasiek

Hello René,

I apologize for the delay in answering your question here.

You opened a support ticket at epesi.cloud as well but it looks like instead of using the ticketing system you started this forum post. I am closing the ticket, since you are not replying to it there, and we will keep the conversation here to the benefit of other users.

As for the error - please read carefully what it says:

Message: mysqli error: [1451: Cannot delete or update a parent row: a foreign key constraint fails (usr_web606_5.session_client, CONSTRAINT session_client_ibfk_1FOREIGN KEY (session_name) REFERENCESsession(name`))] in EXECUTE("DELETE FROM session WHERE name='c7ee89899cf536e7a195ba2bcc072be2'")

Go to PhpMyAdmin and delete all session entries making sure that foreign key is unchecked.

Check all
Delete
Uncheck: enable foreign key checks (if checked the DELETE query will fail)
YES - to confirm

Make sure that both tables are empty:

session
session_client

Your /data/config.php file contains a directive where to store sessions. Options are:

file
database
memcache

Find a section that reads:

define('DIRECTION_RTL','0');
define('EPESI_URL','https://YourEpesiURL');

and find a line that defines how the sessions are handled:

Default: database driver

define('SESSION_TYPE','sql');

define("MEMCACHE_SESSION_SERVER","127.0.0.1:11211");
define('SESSION_TYPE','memcache');

define('SESSION_TYPE','file');

Memcached sessions are the fastest but you have to make sure Memcached deamon is running and you have PHP memcached extension enabled.

File sessions are the slowest, but easiest to setup.

If you experience errors in PHP with Epesi Directory, then add the following:

define('EPESI_DIR', '/');

To troubleshoot errors make sure that you can run phpinfo(); and note where PHP error logs are written. Then generate an error on purpose and see if the PHP error log reflects that.

Your answers will be in:

apache or other HTTP deamon error or access log
PHP error log (if enabled and configured correctly)

Good luck and please paste your results (think about other users in your situation).

Jasiek

digamcrown

Hello and thank you for your help Jasiek.

I emptied the tables in the database as described. After that I commented out the following line in my config.php.
//define('SESSION_TYPE','sql');
And replaced with this line.
define('FILE_SESSION_DIR','/tmp');

My config.php contained only the following line.
define("DIRECTION_RTL","0");

Below that I added this line and since then there have been no further error messages.
define('EPESI_URL','http://epesi.rene-kaufhold.de/'); ?>

Thank you again for your help.
All the best and best regards from Thuringia

jasiek

@digamcrown Thank you for the update and I am glad you made it work.

I was not clear enough with my instructions. When you deleted all records in session tables Epesi should start fine and you should see new records, new sessions in these tables. You should check if this is what is happening. If it works maybe leave it with SQL session type - I don't know how your server is setup. What you can do is test the performance in each case using F12 - Developer Tools and observe Network load performance.

Compare load times in both cases and choose more efficient version.
While you are at that check if you have memache installed. Here is a simple script that not only checks for PHP extension, but actually does a test read/write to memcache database deamon:

<?php

$memcache = new Memcache;
 $memcache->connect("localhost",11211); # You might need to set "localhost" to "127.0.0.1"
 echo "Server's version: " . $memcache->getVersion() . "<br />\n";
 $tmp_object = new stdClass;
 $tmp_object->str_attr = "test";
 $tmp_object->int_attr = 123;
 $memcache->set("key",$tmp_object,false,10);
 echo "Store data in the cache (data will expire in 10 seconds)<br />\n";
 echo "Data from the cache:<br />\n";
 var_dump($memcache->get("key"));

?>

If you verify that memcache works - switch to it, this should give you the best performance and you will get fewer session lock errors. But don't take my word for it - test and verify it yourself.

Make sure that you test session with new browser session - another browser works the best, incognito/private mode window is another option.

You can also uncomment and set all DEBUG options in config.php and in that case Epesi will print at the bottom a lot of information: module load time, module's SQL query times, running totals etc. We used it extensively in the early development phase of Epesi to make sure, that it will work even on very slow 256kB Internet connection (upload speed) popular at that time in Poland. Epesi was designed to work on low end hardware and has very low disk space or bandwidth or CPU or RAM requirements. Both server side and desktop client side.

In fact you can run Epesi on Raspberry Pi:
https://github.com/jtylek/RasPiEsi

Also all the best.
If you do the above and have some spare time please post your results with some specs of your host/server for reference. Thank you in advance.

Janusz Tylek (a.k.a. "jasiek")
Epesi Developer

Epesi ENS | Epesi Academy | epesi.cloud PaaS | GitHub

Help Me! | Download from SourceForge