Your table_definition_cache is too low

[tiotrom]

I see this warning in the admin panel:
Your table_definition_cache is too low (400). This can lead to the database error "Prepared statement needs to be re-prepared". Please set it at least to 405 (or -1 for autosizing). See here for more information.

I've been talking to friendica's admins and devs here https://social.trom.tf/display/dbc8dc44-1360-3da1-2dc9-0f7804630652 but it was suggested that I also ask you here since this is a Friendica ynh install. To increase the table_definition_cache what file I should change and how. Can you please help? Cheers!

[tiotrom]

I installed mysqltuner and these are the outputs:

mysqltuner
 >>  MySQLTuner 1.7.13 - Major Hayden <[email protected]>
 >>  Bug reports, feature requests, and downloads at http://mysqltuner.com/
 >>  Run with '--help' for additional options and output filtering

[--] Skipped version check for MySQLTuner script
Please enter your MySQL administrative login: root
Please enter your MySQL administrative password: [OK] Currently running supported MySQL version 10.3.27-MariaDB-0+deb10u1
[OK] Operating on 64-bit architecture
 
-------- Log file Recommendations ------------------------------------------------------------------
[--] Log file: /var/lib/mysql/trom.tf.err(1K)
[OK] Log file /var/lib/mysql/trom.tf.err exists
[!!] Log file /var/lib/mysql/trom.tf.err isn't readable.
 
-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +Aria +CSV +InnoDB +MEMORY +MRG_MyISAM +MyISAM +PERFORMANCE_SCHEMA +SEQUENCE 
[--] Data in InnoDB tables: 166.0M (Tables: 188)
[--] Data in MyISAM tables: 988.5K (Tables: 2)
[--] Data in MEMORY tables: 0B (Tables: 1)
[OK] Total fragmented tables: 0
 
-------- Analysis Performance Metrics --------------------------------------------------------------
[--] innodb_stats_on_metadata: OFF
[OK] No stat updates during querying INFORMATION_SCHEMA.
 
-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[OK] All database users have passwords assigned
[--] There are 618 basic passwords in the list.
 
-------- CVE Security Recommendations --------------------------------------------------------------
[OK] NO SECURITY CVE FOUND FOR YOUR VERSION
 
-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 14h 35m 54s (4M q [89.498 qps], 35K conn, TX: 7G, RX: 774M)
[--] Reads / Writes: 95% / 5%
[--] Binary logging is disabled
[--] Physical Memory     : 59.0G
[--] Max MySQL memory    : 430.6M
[--] Other process memory: 7.5G
[--] Total buffers: 289.0M global + 960.0K per thread (151 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 322.8M (0.53% of installed RAM)
[OK] Maximum possible memory usage: 430.6M (0.71% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (0/4M)
[OK] Highest usage of available connections: 23% (36/151)
[OK] Aborted connections: 0.02%  (6/35144)
[!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance
[!!] Query cache may be disabled by default due to mutex contention.
[!!] Query cache efficiency: 0.0% (0 cached / 4M selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 362K sorts)
[!!] Joins performed without indexes: 322
[OK] Temporary tables created on disk: 1% (4K on disk / 274K total)
[OK] Thread cache hit rate: 99% (37 created / 35K connections)
[!!] Table cache hit rate: 0% (10 open / 1M opened)
[OK] Open file limit used: 0% (5/760)
[OK] Table locks acquired immediately: 100% (84 immediate / 84 locks)
 
-------- Performance schema ------------------------------------------------------------------------
[--] Performance schema is disabled.
[--] Memory used by P_S: 0B
[--] Sys schema isn't installed.
 
-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is enabled.
[--] Thread Pool Size: 10 thread(s).
[--] Using default value is good enough for your version (10.3.27-MariaDB-0+deb10u1)
 
-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 50.0% (8K used / 16K cache)
[!!] Key buffer size / total MyISAM indexes: 16.0K/146.0K
[!!] Read Key buffer hit rate: 84.4% (308 cached / 48 reads)
[!!] Write Key buffer hit rate: 77.8% (18 cached / 14 writes)
 
-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[!!] InnoDB buffer pool / data size: 128.0M/166.0M
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (75 %): 48.0M * 2/128.0M should be equal 25%
[OK] InnoDB buffer pool instances: 1
[--] Number of InnoDB Buffer Pool Chunk : 1 for 1 Buffer Pool Instance(s)
[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances
[OK] InnoDB Read buffer efficiency: 99.83% (200488812 hits/ 200831446 total)
[!!] InnoDB Write Log efficiency: 65.91% (395724 hits/ 600368 total)
[OK] InnoDB log waits: 0.00% (0 waits / 204644 writes)
 
-------- AriaDB Metrics ----------------------------------------------------------------------------
[--] AriaDB is enabled.
[OK] Aria pagecache size / total Aria indexes: 128.0M/1B
[!!] Aria pagecache hit rate: 89.6% (21K cached / 2K reads)
 
-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.
 
-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.
 
-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.
 
-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] Binlog format: MIXED
[--] XA support enabled: ON
[--] Semi synchronous replication Master: OFF
[--] Semi synchronous replication Slave: OFF
[--] This is a standalone server
 
-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
    MySQL was started within the last 24 hours - recommendations may be inaccurate
    Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
    Adjust your join queries to always utilize indexes
    Increase table_open_cache gradually to avoid file descriptor limits
    Read this before increasing table_open_cache over 64: http://bit.ly/1mi7c4C
    Read this before increasing for MariaDB https://mariadb.com/kb/en/library/optimizing-table_open_cache/
    This is MyISAM only table_cache scalability problem, InnoDB not affected.
    See more details here: https://bugs.mysql.com/bug.php?id=49177
    This bug already fixed in MySQL 5.7.9 and newer MySQL versions.
    Beware that open_files_limit (760) variable 
    should be greater than table_open_cache (10)
    Performance schema should be activated for better diagnostics
    Consider installing Sys schema from https://github.com/mysql/mysql-sys
    Before changing innodb_log_file_size and/or innodb_log_files_in_group read this: https://bit.ly/2TcGgtU
Variables to adjust:
    query_cache_size (=0)
    query_cache_type (=0)
    query_cache_limit (> 1M, or use smaller result sets)
    join_buffer_size (> 256.0K, or always use indexes with JOINs)
    table_open_cache (> 10)
    performance_schema = ON enable PFS
    key_buffer_size (> 146.0K)
    innodb_buffer_pool_size (>= 166.0M) if possible.
    innodb_log_file_size should be (=16M) if possible, so InnoDB total log files size equals to 25% of buffer pool size.

[hieronymousch]

I can confirm this issue on my instance. I had to manually add table_definition_cache = 500 in mariadb.cnf

[tiotrom]

I can confirm this issue on my instance. I had to manually add table_definition_cache = 500 in mariadb.cnf

Thanks. That fixed it for me ;)

[anmol26s]

@tiotrom
@hieronymousch
Last time I did that on my test server it changed nothing related to the error message. Maybe I forgot to restart the mysql. I will try it in next rounds of improvements. Fail2ban needs to implemented and I would use git for install and updating rather then app.src.
Can you tell me what did you changed?

[tiotrom]

I added table_definition_cache = 500 in mariadb.cnf under [mysqld] and restarted mysql.

[anmol26s]

I let it open till its fixed.

[tio-trom]

This is an old issue and I am not experiencing this anymore. It was opened from another account of mine so I cannot close the issue. If anyone can please do. Thanks!