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[Maria-discuss] Restore from mysqldump fails with "Error in foreign key constraint"
by Alex 03 Jun '23

03 Jun '23

Hi, I'm trying to use mysqlbackup to backup a mariadb-10.5.19 database on fedora37 server using the following: # mysqldump --verbose -u root -ppass --result-file=/var/backup/mysql-backup/backup-lsalex-2023-06-03-13008.sql lsalex I usually use a more involved mysqlbackup command, but it also failed, so I figured it would be better to start out more simply as above. It fails with the following when restoring to a new, test database: # mysql -u root -p lstest < /var/backup/mysql-backup/backup-lsalex-2023-06-03-13008.sql Enter password: ERROR 1005 (HY000) at line 12884: Can't create table `lsalex`.`xu6gc_tj_notification_user_exclusions` (errno: 150 "Foreign key constraint is incorrectly formed") This is a backup/restore of a Joomla database. Am I using the wrong command to perform the backup or restore? This isn't a database that I created and I really have no idea how it works. I've also searched extensively for this error, and it appears to be a programming error, not a database error, but obviously I have no control over Joomla programming. Here's what I found from "SHOW ENGINE INNODB STATUS": LATEST FOREIGN KEY ERROR ------------------------ 2023-06-03 10:09:01 0x7f3a8d8516c0 Error in foreign key constraint of table `lstest`.`xu6gc_tj_notification_user_exclusions`: Create table `lstest`.`xu6gc_tj_notification_user_exclusions` with foreign key `xu6gc_tj_notification_user_exclusions_ibfk_1` constraint failed. Field type or character set for column 'provider' does not match referenced column 'provider'.------------ Here's the lines from the backup mentioned in the error message: 12884 CREATE TABLE `xu6gc_tj_notification_user_exclusions` ( 12885 `user_id` int(11) NOT NULL, 12886 `client` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL, 12887 `key` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL, 12888 `provider` varchar(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NOT NULL, 12889 KEY `client1` (`client`,`provider`(50),`key`), 12890 KEY `key` (`key`), 12891 KEY `provider` (`provider`), 12892 CONSTRAINT `xu6gc_tj_notification_user_exclusions_ibfk_1` FOREIGN KEY (`provider`) REFERENCES `xu6gc_tj_notification_providers` (`provider`) 12893 ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_general_ci; Any ideas are greatly appreciated.

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Re: [Maria-discuss] Backup on the replication server getting affected
by andrei.elkin＠pp.inet.fi 02 Jun '23

02 Jun '23

Howdy Ragul, > Hi Andrei, > > Do we have any procedures to reproduce the issue MDEV-30780? Thanks for posting the gdb bt:s. They rule out 30780 yet not suggesting to me enough about the hang reason. This is something new to me and does deserve filing an MDEV ticket. Still I'd defer that until one has confirmed the same issue is seen on the latest 10.6. So you could run your load against the most recent slave version that'd be at least the safest (for our time). It might be (a slave worker) Thread 80 spinning inside #6 0x000055de407a0a3c in log_write_up_to (lsn=<optimized out>, lsn@entry=216757233923297, flush_to_disk=flush_to_disk@entry=false, rotate_key=rotate_key@entry=false, a goto repeat "loop". That hopefully you can confirm any next time the hang appears back. Could you please check whether #6 calls iteratively indeed `group_commit_lock::release()`? (With e.g (gdb) br thd_decrement_pending_ops thread 80 of course the number may change:-)). All the other slave worker threads may be waiting for the 80 but I can't confirm that until more data gets available. Namely I need to see the output of (gdb) thr app all get_about_worker_thread where the latter is defined as define get_about_worker_thread if $_any_caller_is ("handle_rpl_parallel_thread", 50) bt p handle_rpl_parallel_thread::rpt if (handle_rpl_parallel_thread::rpt->thd->rgi_slave) p handle_rpl_parallel_thread::rpt->thd->rgi_slave p handle_rpl_parallel_thread::rpt->thd->rgi_slave->current_gtid p handle_rpl_parallel_thread::rpt->thd->rgi_slave->gtid_sub_id p handle_rpl_parallel_thread::rpt->thd->rgi_slave->worker_error end end end > Unable to reproduce the issue locally but it occurs at random. to require some more patience from us. I belive we can resolve it while you're helping so generously! Cheers, Andrei > > Regards, > Ragul > > On Mon, May 29, 2023 at 7:06 PM ragul rangarajan <ragulrangarajan(a)gmail.com> wrote: > > Thanks Andrei, > > Hope my issue is more related to the issue MDEV-30780 optimistic parallel slave hangs after hit an error > Trying to reproduce with a minimal database.

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[Maria-discuss] FYI:10.5.15-MariaDB crash und recover
by Radisson97＠gmx.de 01 Jun '23

01 Jun '23

Hello I had a crash today, there was no problem with the hardware. Maybe someone is interessted or find some useful information. It is a production machine so no core file. have fun. btw: Linux 5.10.0-17-amd64 #1 SMP Debian 5.10.136-1 == mariadb.log == 230601 8:22:09 [ERROR] mysqld got signal 11 ; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. To report this bug, see https://mariadb.com/kb/en/reporting-bugs We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. Server version: 10.5.15-MariaDB-0+deb11u1-log key_buffer_size=134217728 read_buffer_size=131072 max_used_connections=11 max_threads=252 thread_count=11 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 685818 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x7faf440061d8 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 0x7fafa439bd38 thread_stack 0x49000 ??:0(my_print_stacktrace)[0x55ebc2f0954e] ??:0(handle_fatal_signal)[0x55ebc2a08f65] sigaction.c:0(__restore_rt)[0x7fb11f670140] ??:0(_ma_state_info_write)[0x55ebc2bfdc73] ??:0(_ma_state_info_write)[0x55ebc2bff737] ??:0(_ma_state_info_write)[0x55ebc2c0746c] ??:0(handler::ha_write_row(unsigned char const*))[0x55ebc2a15aa8] ??:0(MyCTX_nopad::finish(unsigned char*, unsigned int*))[0x55ebc2c420da] ??:0(handler::ha_write_row(unsigned char const*))[0x55ebc2a15aa8] ??:0(write_record(THD*, TABLE*, st_copy_info*, select_result*))[0x55ebc27d587d] ??:0(mysql_insert(THD*, TABLE_LIST*, List<Item>&, List<List<Item> >&, List<Item>&, List<Item>&, enum_duplicates, bool, select_result*))[0x55ebc 27dd8a4] ??:0(mysql_execute_command(THD*))[0x55ebc2810716] ??:0(mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool))[0x55ebc28145db] ??:0(dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool))[0x55ebc2816a5d] ??:0(do_command(THD*))[0x55ebc28182de] ??:0(do_handle_one_connection(CONNECT*, bool))[0x55ebc2909fb2] ??:0(handle_one_connection)[0x55ebc290a22d] ??:0(MyCTX_nopad::finish(unsigned char*, unsigned int*))[0x55ebc2c4611b] nptl/pthread_create.c:478(start_thread)[0x7fb11f664ea7] x86_64/clone.S:97(__GI___clone)[0x7fb11f27bdef] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (0x7faf44014860): INSERT INTO wetter_daten VALUES ( 190600010 , '2023-06-01 06:00:00' , 0 , 0 ) Connection ID (thread ID): 5569194 Status: NOT_KILLED Optimizer switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,e ngine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in _to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=o ff,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=o n,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,cond ition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off The manual page at https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mysqld/ contains information that should help you find out what is causing the crash. Writing a core file... Working directory at /home/kpc/kpc.dbs Resource Limits: Limit Soft Limit Hard Limit Units Max cpu time unlimited unlimited seconds Max file size unlimited unlimited bytes Max data size unlimited unlimited bytes Max stack size 8388608 unlimited bytes Max core file size 0 unlimited bytes Max resident set unlimited unlimited bytes Max processes 127967 127967 processes Max open files 32313 32313 files Max locked memory 65536 65536 bytes Max address space unlimited unlimited bytes Max file locks unlimited unlimited locks Max pending signals 127967 127967 signals Max msgqueue size 819200 819200 bytes Max nice priority 0 0 Max realtime priority 0 0 Max realtime timeout unlimited unlimited us Core pattern: core 230601 08:22:10 mysqld_safe Number of processes running now: 0 230601 08:22:10 mysqld_safe mysqld restarted 2023-06-01 8:22:11 0 [Note] /usr/sbin/mariadbd (mysqld 10.5.15-MariaDB-0+deb11u1-log) starting as process 24005 ... 2023-06-01 8:22:11 0 [Note] mariadbd: Aria engine: starting recovery recovered pages: 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% (0.1 seconds); tables to flush: 62 61 60 59 58 57 56 55 54 53 52 51 50 49 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 (0.4 seconds); 2023-06-01 8:22:11 0 [Note] mariadbd: Aria engine: recovery done 2023-06-01 8:22:11 0 [Note] InnoDB: Uses event mutexes 2023-06-01 8:22:11 0 [Note] InnoDB: Compressed tables use zlib 1.2.11 2023-06-01 8:22:11 0 [Note] InnoDB: Number of pools: 1 2023-06-01 8:22:11 0 [Note] InnoDB: Using crc32 + pclmulqdq instructions 2023-06-01 8:22:11 0 [Note] InnoDB: Using Linux native AIO 2023-06-01 8:22:11 0 [Note] InnoDB: Initializing buffer pool, total size = 5368709120, chunk size = 134217728 2023-06-01 8:22:11 0 [Note] InnoDB: Completed initialization of buffer pool 2023-06-01 8:22:11 0 [Note] InnoDB: Starting crash recovery from checkpoint LSN=463015889782,463015889782 2023-06-01 8:22:13 0 [Note] InnoDB: Starting final batch to recover 2019 pages from redo log. 2023-06-01 8:22:15 0 [Note] InnoDB: 128 rollback segments are active. 2023-06-01 8:22:15 0 [Note] InnoDB: Removed temporary tablespace data file: "ibtmp1" 2023-06-01 8:22:15 0 [Note] InnoDB: Creating shared tablespace for temporary tables 2023-06-01 8:22:15 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ... 2023-06-01 8:22:15 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB. 2023-06-01 8:22:15 0 [Note] InnoDB: 10.5.15 started; log sequence number 463033688604; transaction id 19549881 2023-06-01 8:22:15 0 [Note] InnoDB: Loading buffer pool(s) from /home/kpc/kpc.dbs/ib_buffer_pool 2023-06-01 8:22:15 0 [Note] Plugin 'FEEDBACK' is disabled. 2023-06-01 8:22:15 0 [Note] Server socket created on IP: '::'. 2023-06-01 8:22:16 0 [Note] Reading of all Master_info entries succeeded 2023-06-01 8:22:16 0 [Note] Added new Master_info '' to hash table 2023-06-01 8:22:16 0 [Note] /usr/sbin/mariadbd: ready for connections. Version: '10.5.15-MariaDB-0+deb11u1-log' socket: '/run/mysqld/mysqld.sock' port: 3306 Debian 11 2023-06-01 8:22:18 0 [Note] InnoDB: Buffer pool(s) load completed at 230601 8:22:18

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[Maria-discuss] jujst re-joined trial e-mail don't read
by antonio scotti 30 May '23

30 May '23

=============================================== PermaCultura-es http://www.permacultura-es.org

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[Maria-discuss] trial e-mail don't read
by antonio scotti 30 May '23

30 May '23

=============================================== PermaCultura-es http://www.permacultura-es.org

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[Maria-discuss] Innodb_buffer_pool_read_requests is zero
by mariadb＠Biblestuph.com 19 May '23

19 May '23

Just upgraded from 10.6.12 to 10.6.13 on a Debian Bullseye system, and seeing this oddity. Innodb_buffer_pool_read_requests is zero, and seems to remain at zero no matter what I do (I even tried selecting all the data from a small table several times in a row with no change). It's been running a couple hours now; I've restarted it a couple times. I have 10.6.13 on a few other platforms as well (including Buster), and I'm not seeing the same issue on them. What would cause this? I have no other Bullseye systems running 10.6.13 yet, and the same system has been running 10.6.12 for over a week now without showing this issue. The system _seems_ to be running fine, it's a replica system that is being fed actively from the master (data comes in to it very regularly). MariaDB [(none)]> SHOW GLOBAL STATUS LIKE 'innodb_buffer_pool_%'; +-----------------------------------------+--------------------------------------------------+ | Variable_name | Value | +-----------------------------------------+--------------------------------------------------+ | Innodb_buffer_pool_dump_status | | | Innodb_buffer_pool_load_status | Buffer pool(s) load completed at 230511 23:21:26 | | Innodb_buffer_pool_resize_status | | | Innodb_buffer_pool_load_incomplete | OFF | | Innodb_buffer_pool_pages_data | 609103 | | Innodb_buffer_pool_bytes_data | 9979543552 | | Innodb_buffer_pool_pages_dirty | 19465 | | Innodb_buffer_pool_bytes_dirty | 318914560 | | Innodb_buffer_pool_pages_flushed | 0 | | Innodb_buffer_pool_pages_free | 299441 | | Innodb_buffer_pool_pages_made_not_young | 0 | | Innodb_buffer_pool_pages_made_young | 107 | | Innodb_buffer_pool_pages_misc | 0 | | Innodb_buffer_pool_pages_old | 224824 | | Innodb_buffer_pool_pages_total | 908544 | | Innodb_buffer_pool_pages_lru_flushed | 0 | | Innodb_buffer_pool_pages_lru_freed | 0 | | Innodb_buffer_pool_pages_split | 726 | | Innodb_buffer_pool_read_ahead_rnd | 0 | | Innodb_buffer_pool_read_ahead | 3 | | Innodb_buffer_pool_read_ahead_evicted | 0 | | Innodb_buffer_pool_read_requests | 0 | | Innodb_buffer_pool_reads | 604346 | | Innodb_buffer_pool_wait_free | 0 | | Innodb_buffer_pool_write_requests | 3639341 | +-----------------------------------------+--------------------------------------------------+ 25 rows in set (0.000 sec) MariaDB [(none)]> SHOW VARIABLES LIKE 'innodb_buffer_pool%'; +-------------------------------------+----------------+ | Variable_name | Value | +-------------------------------------+----------------+ | innodb_buffer_pool_chunk_size | 134217728 | | innodb_buffer_pool_dump_at_shutdown | ON | | innodb_buffer_pool_dump_now | OFF | | innodb_buffer_pool_dump_pct | 80 | | innodb_buffer_pool_filename | ib_buffer_pool | | innodb_buffer_pool_load_abort | OFF | | innodb_buffer_pool_load_at_startup | ON | | innodb_buffer_pool_load_now | OFF | | innodb_buffer_pool_size | 15032385536 | +-------------------------------------+----------------+ 9 rows in set (0.000 sec)

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[Maria-discuss] Question regarding mariadb-dump/mysqldump and rocksdb
by Jonas Krauss 16 May '23

16 May '23

Hi MariaDB, in Myrocks / Facebook MySQL there was a useful addition to mysqldump which makes queries issued by the dumper not add to the block cache of the rocksdb instance. It was added quite some time ago: https://github.com/facebook/mysql-5.6/commit/2223479fea78a246884c5a09ef4d02… The corresponding server variable used is *rocksdb_skip_fill_cache* Is this active in MariaDB's version of mysqldump as well? The server variable exists in MariaDB's MyRocks (checked for 10.6.12) but I have not found a reference in MariaDB's source code when searching for rocksdb_skip_fill_cache. If it is not active it would be great if it could be added in a future version. Best Jonas

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[Maria-discuss] Undo logs aren't truncating
by mariadb＠Biblestuph.com 15 May '23

15 May '23

On a recently updated MariaDB 10.6.13 server (Debian Bullseye) I noticed that my ibdata1 file was continuously growing; it had gotten a little over 3G after running a couple days. I would rather keep this growth in check so used it as an excuse to setup undo tablespaces that could be truncated (I had wanted to try this for some time anyway). So: Dump the whole DB, delete all the InnoDB tables, stop the server, delete the innodb system tables, reset the appropriate undo variables (with innodb_max_undo_log_size set to 750M, innodb_undo_tablespaces set to 4, and innodb_undo_log_truncate set to ON), restart the server and reload the data. I now have FOUR undo files that appear to be continuously growing; as of this writing they are over 1G and still increasing. This is an active read-only replica (processing updates very frequently; at times continuously but not constantly as such). How do I get it to actually reclaim the space? Or am I misunderstanding how this is supposed to work? Below are my current relevant settings (or at least what I think are relevant). Normally I run with innodb_purge_rseg_truncate_frequency = 128; but for testing I have it now set to 1 (but with no noticeable difference). Things I have tried (no luck on any of them): Set innodb_purge_rseg_truncate_frequency = 1. Set innodb_max_purge_lag_wait=0 (it returned nearly immediately). Stop both slave threads and wait for several minutes. Set innodb_max_purge_lag and innodb_max_purge_lag_delay (see below). MariaDB [(none)]> show variables like '%trunc%'; +--------------------------------------+-------+ | Variable_name | Value | +--------------------------------------+-------+ | innodb_purge_rseg_truncate_frequency | 1 | | innodb_undo_log_truncate | ON | +--------------------------------------+-------+ 2 rows in set (0.000 sec) MariaDB [(none)]> show variables like '%purge%'; +--------------------------------------+------------+ | Variable_name | Value | +--------------------------------------+------------+ | aria_log_purge_type | immediate | | innodb_max_purge_lag | 1000 | | innodb_max_purge_lag_delay | 5000 | | innodb_max_purge_lag_wait | 4294967295 | | innodb_purge_batch_size | 300 | | innodb_purge_rseg_truncate_frequency | 1 | | innodb_purge_threads | 4 | | relay_log_purge | ON | +--------------------------------------+------------+ 8 rows in set (0.000 sec) MariaDB [(none)]> show variables like '%undo%'; +--------------------------+-----------+ | Variable_name | Value | +--------------------------+-----------+ | innodb_max_undo_log_size | 786432000 | | innodb_undo_directory | ./ | | innodb_undo_log_truncate | ON | | innodb_undo_tablespaces | 4 | +--------------------------+-----------+ 4 rows in set (0.000 sec)

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[Maria-discuss] mariadb crash und recovery
by Radisson97＠gmx.de 14 May '23

14 May '23

Hello list, i had a crash at weekend with no apparend cause. The aria engine did a recovery without furture problems. Maybe that is a hint that somebody can make use of. Hints welcome. CU from log: 230416 7:20:17 [ERROR] mysqld got signal 11 ; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. To report this bug, see https://mariadb.com/kb/en/reporting-bugs We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. Server version: 10.5.15-MariaDB-0+deb11u1-log key_buffer_size=134217728 read_buffer_size=131072 max_used_connections=86 max_threads=252 thread_count=38 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 685818 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x7f01e4000c58 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 0x7f02b6894d38 thread_stack 0x49000 ??:0(my_print_stacktrace)[0x5559d92bb54e] ??:0(handle_fatal_signal)[0x5559d8dbaf65] sigaction.c:0(__restore_rt)[0x7f043591a140] ??:0(_ma_state_info_write)[0x5559d8fafc73] ??:0(_ma_state_info_write)[0x5559d8fb1737] ??:0(_ma_state_info_write)[0x5559d8fb946c] ??:0(handler::ha_write_row(unsigned char const*))[0x5559d8dc7aa8] ??:0(MyCTX_nopad::finish(unsigned char*, unsigned int*))[0x5559d8ff40da] ??:0(handler::ha_write_row(unsigned char const*))[0x5559d8dc7aa8] ??:0(write_record(THD*, TABLE*, st_copy_info*, select_result*))[0x5559d8b8787d] ??:0(mysql_insert(THD*, TABLE_LIST*, List<Item>&, List<List<Item> >&, List<Item>&, List<Item>&, enum_duplicates, bool, select _result*))[0x5559d8b8f8a4] ??:0(mysql_execute_command(THD*))[0x5559d8bc2716] ??:0(mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool))[0x5559d8bc65db] ??:0(dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool))[0x5559d8bc8a5d] ??:0(do_command(THD*))[0x5559d8bca2de] ??:0(do_handle_one_connection(CONNECT*, bool))[0x5559d8cbbfb2] ??:0(handle_one_connection)[0x5559d8cbc22d] ??:0(MyCTX_nopad::finish(unsigned char*, unsigned int*))[0x5559d8ff811b] nptl/pthread_create.c:478(start_thread)[0x7f043590eea7] x86_64/clone.S:97(__GI___clone)[0x7f0435525def] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (0x7f01e4010440): INSERT INTO messwerte VALUES ( 83110995 , 1200 , 909 , 331 , '2023-04-16 05:20:00' , '2023-04-16 05: 20:00' , 0.0703000000000000013766765505351941101253032684326171875 , 0.001000000000000000020816681711721685132943093776702880 859375 , 0 , 0 , 0 , 0 , 60 , 0 ) Connection ID (thread ID): 5463672 Status: NOT_KILLED Optimizer switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_ intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=o n,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subque ry_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_increment al=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=on,table_elimination=on,extended_keys=on,exists_to_in= on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowi d_filter=on,condition_pushdown_from_having=on,not_null_range_scan=off The manual page at https://mariadb.com/kb/en/how-to-produce-a-full-stack-trace-for-mysqld/ contains information that should help you find out what is causing the crash. Writing a core file... Working directory at /home/kpc/kpc.dbs Resource Limits: Limit Soft Limit Hard Limit Units Max cpu time unlimited unlimited seconds Max file size unlimited unlimited bytes Max data size unlimited unlimited bytes Max stack size 8388608 unlimited bytes Max core file size 0 unlimited bytes Max resident set unlimited unlimited bytes Max processes 127976 127976 processes Max open files 32313 32313 files Max locked memory 65536 65536 bytes Max address space unlimited unlimited bytes Max file locks unlimited unlimited locks Max pending signals 127976 127976 signals Max msgqueue size 819200 819200 bytes Max nice priority 0 0 Max realtime priority 0 0 Max realtime timeout unlimited unlimited us Core pattern: core 230416 07:20:19 mysqld_safe Number of processes running now: 0 230416 07:20:19 mysqld_safe mysqld restarted 2023-04-16 7:20:19 0 [Note] /usr/sbin/mariadbd (mysqld 10.5.15-MariaDB-0+deb11u1-log) starting as process 415 ... 2023-04-16 7:20:20 0 [Note] mariadbd: Aria engine: starting recovery recovered pages: 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% (0.0 seconds); tables to flush: 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 (0.1 seconds); 2023-04-16 7:20:20 0 [Note] mariadbd: Aria engine: recovery done

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[Maria-discuss] Checkpoint Age and Redo Log Flushing in 10.5+
by Gordan Bobic 14 May '23

14 May '23

Ever since 10.5, the redo log flushing seems to have become ... suboptimal. It looks like the database does nothing at all to flush the logs until it hits the hwm, and then it goes into overdrive and flushes everything to tablespaces fast, before it goes back to doing nothing until the log fills up. This causes a problem when the redo log is already full and a large burst of writes arrives because it overwhelms the redo log and causes a stall. Is there a bug fix for this or a configuration change available to restore the old behaviour where everything gets flushed continuously and switches up a gear when the hwm is reached? Here are the screenshots comparing 10.5+ sawtooth pattern vs 10.4 and older versions.

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