Hello Kopano-Team,

we got a bunch of Outlook 2010, accessing Kopano directly via MAPI.

Some People who accept meeting-request (for their own) are getting Errors:
“Database or I/O Error”

On the Server i’m getting following error:

Tue Feb 13 14:27:26 2018: [error  ] SQL [00082009] Failed: Deadlock found when trying to get lock; try restarting transaction, Query Size: 127, Query: "UPDATE properties SET val_ulong = IF (val_ulong >= 1, val_ulong + -1, 0) WHERE hierarchyid = 62529 AND tag = 13826 AND type = 3"
Tue Feb 13 14:27:26 2018: [error  ] KDatabase::I_Update() query failed: UPDATE properties SET val_ulong = IF (val_ulong >= 1, val_ulong + -1, 0) WHERE hierarchyid = 62529 AND tag = 13826 AND type = 3: Deadlock found when trying to get lock; try restarting transaction
Tue Feb 13 14:27:26 2018: [info   ] Error while deleting expanded item list, error code 2147483655

is there some sort of script who can fix this (maybe fix herachy script? - dont want to run it unless i know this will help)
in my opinion this could be some sort of db misconfiguration. here my my.cnf/kopano.cnf under my.d:
my.cnf

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
default-storage-engine=InnoDB
[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid
!includedir /etc/my.cnf.d

kopano.cnf:

[mysqld]
datadir=/export/data/mail/db
innodb_buffer_pool_size = 8192M
innodb_log_file_size = 512M
innodb_log_buffer_size = 16M
max_allowed_packet = 64M
max_connections = 100
innodb_file_per_table=1
long_query_time = 5
query_cache_size = 64M
#thread_cache_size = 80 ##//good value= number of kopano-threads + 1 // currently 8 threads
thread_cache_size = 9
### known as "table_cache" in versions 5.1 and earlier (Kopano tables + max mysql connections) * 10, for example (26 + 100 ) * 10 (at max_connection=100 not possible max usable 500 users)
table_open_cache = 500

# Primer tuning
#join_buffer_size = 256K  ##edited recommended by kopano set to max (2M) regardless of size of environment)
join_buffer_size = 2M
innodb_buffer_pool_instances = 2



##NEW recommended by kopano
sort_buffer_size = 2M
transaction-isolation = READ-COMMITTED

## in order to use "enable_sql_procedures = yes" in kopano.cfg we need at least 512K
thread_stack = 512K

# RHEL6 do no use any query cache size !! kills performance - we got RHEL7 so we are using recommended settings
query_cache_size = 64M
query_cache_limit = 2M

## only in 5.5 or higher   thumb-rule= cores/2 ~  4/2 = 2  
innodb_write_io_threads = 2
innodb_read_io_threads = 2

## in case of remote storage: innodb_flush_method = O_DIRECT    ###OTHERWISE (ours - we are using ISCSI at ESXI) -> innodb_flush_method = O_DSYNC
innodb_flush_method = O_DSYNC

System: 8 cores, 24GB ram - all other infos are in my signature

thanks in advance

coffee_is_life