Massive logfile size due to cron.php

I am using NC 9.0.53 in an alpine docker container with php7. Cron.php is executed every 15minutes via crond.
As soon as the cron.php gets executed it creates a log entry of about 12MB.
It contains a lot of what seems to be hash values, example:

yHUIw5HehCJJcKprMZgWOPwq5fy7VCDqazxnOKbEPzRmkwT2qQIaSQxB7U8\\r\\n A4zTljyOamWPAFOwiNAeoGTUkNu3mBjUqgDtUy9OBTC4+OPAqZFGevao1b\\\/9VPFBLJ1Ga6jwSu\\r\\n 3xdpJH\\\/Pyn865hDwK6jwYceLNK\\\/wCvlP50PYEfS+KMUtFYjsJijHtS0UtAsJioWtYHOXhjY+pU\\r\\n VPRQPQ5XxppNtc+GrhvIRWiw6sqgEV5z4U0+K88TWkU0ayRliWVvTFewazCbjRbyIDJaJsCvM\\\/\\r\\n AkBfxVG2CfLRifbtWkLcpNkeijw3pQBC2UYB9CaE8NaVH0s0\\\/HmtYGlrLlQcqMj\\\/hGtJP\\\/AC5R\\r\\n 0Vr0UcqDliFFFFMoKKKKACiiigAooooAQjOfTFeNfGaMjVbFj0a3P6E\\\/417NXknxnizJpc2OCr\\r\\n pn8Qa0p7iZ4xJ941UlNW5TyapSHrW1iSq5wetQP061O44qu9Qy0Qkn+8aaWYdGNOIppxUMYnmP\\r\\n \\\/epDLIO9BphoGSec553UC4fvUYGKDikO5MbgntTftB7ioqCKNRXJftHtSi4XvmocDFJigCx9oQ\\r\\n +tHmxnvVfFG2ncCwJEPQ04Mh\\\/iFVQKWncOhawnB3CkMg7VXxkjFO6Gi4mSsxkbcecdKUCmDin5\\r\\n oEPA7mpBge9RA\\\/lShqoCYGnhsCoQaeDmgCVWOa6Twr4U1DxZqP2WxARFwZZnHyoP6n2rmUbaeR\\r\\n kelfS\\\/w00hNE8H2pIxNdDzpT3O7oKmTsgR434t8D6l4NuIPtckU1vOxWKaIdSPX0Nc+FxXtvxq\\r\\n li\\\/4ROzRz+9a7DJ68A5\\\/mK8RU\\\/l0pxdyWWFI4IrpvBzBPFOlseguUP4ZrmIhmu3+HukS6p4mhZ\\r\\n ANlt++Ynpx0qnsB9E5parxy

Process running in the container:

    1 root       0:00 /sbin/tini --
    6 root       0:00 {} /bin/sh /usr/local/bin/
   21 root       0:00 {supervisord} /usr/bin/python /usr/bin/supervisord -c /etc/supervisor/supervisord.conf
   24 root       0:00 crond -f
   25 root       0:00 nginx: master process nginx
   26 clamav     0:03 freshclam -d
   27 root       0:00 {php-fpm7} php-fpm: master process (/etc/php7/php-fpm.conf)
   28 clamav     0:27 clamd
   29 nextclou   0:00 nginx: worker process
   30 nextclou   0:00 nginx: worker process
   31 nextclou   0:00 nginx: worker process
   32 nextclou   0:00 nginx: worker process
   33 nextclou   0:45 {php-fpm7} php-fpm: pool www
   34 nextclou   0:46 {php-fpm7} php-fpm: pool www
   43 nextclou   0:41 {php-fpm7} php-fpm: pool www

Has anyone ever expected such a behavior? I disabled the Antivirus App, but same behavior.

without a full log line it will be difficult to judge your “hash”

Hi, I uploaded a logfile to Dropbox with one 12MB dump (I deleted the log first and waited until a the cron.php was executed again).

Download Logfile:

It’s one log entry that turns an avatar from binary into text (thats why its so huge). Your issue is at the bottom:

the size of BLOB\/TEXT data inserted in one transaction is greater than 10% of redo log size. Increase the redo log size using innodb_log_file_size.

but why is it trying to turn a avatar into text? And to which size do I have to increase the redo log size?

It seems that the avatar is stored base64 encoded. As for how to do that:

If anyone encounters the same problem, here is the explanation:

Due to Bug #69477, redo log writes for large, externally stored BLOB fields could overwrite the most recent checkpoint. To address this bug, a patch introduced in MySQL 5.6.20 limits the size of redo log BLOB writes to 10% of the redo log file size. As a result of this limit, innodb_log_file_size should be set to a value greater than 10 times the largest BLOB data size found in the rows of your tables plus the length of other variable length fields (VARCHAR, VARBINARY, and TEXT type fields).

In MySQL 5.6.22, the redo log BLOB write limit is relaxed to 10% of the total redo log size (innodb_log_file_size * innodb_log_files_in_group). (Bug #19498877)