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[Maria-discuss] Expanding Galera cluster
by Thorvald Hallvardsson 04 Jul '16

04 Jul '16

Hi guys, I need some help as I'm preparing to expand my existing Galera cluster. Generally the purpose of it is I need to replace 3 VMs I have a cluster running on to 2 physical servers I have been given for that purpose. My idea was to join 2 physical cluster to the existing cluster of 3 and then remove all 3 VMs from the cluster leaving 2 physical nodes within. I have a arbitrator box within the cluster as well. The config at the moment contains 2 maxscale proxy nodes on the front balancing the read queries across the entire cluster of 3 and write queries to the elected master. What I want to achieve is as I said above but + I will need another help with maxscale to expand and then shrink the cluster down to 2 nodes afterwards. I have had a situation before when I had to do a simple config change on the Galera cluster and I was trying to mark nodes and put them into maintenance mode to stop traffic coming to them but the commands like set server NODE master didn't actually do anything. I had situations when I had 2 masters in the cluster for a second because then something was happening that my manually selected master was becoming a slave again. I couldn't find anything on the internet what would point me into right direction and explain the whole procedure in details. My cluster is quite busy at the moment even overnight so there is no perfect time to do anything on it. I need to do it the least disruptive way and the most controlled way as well. Hence I'm asking for help and suggestions as I found both Galera and maxscale documentation very very brief not actually providing any decent details or procedures. I found much more help from Percona but descriptions don't match sometimes. Please help. Regards, TH

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[Maria-discuss] New Question: Aggregating data with help tables will raise open table cache - solution?
by AskMonty KB 04 Jul '16

04 Jul '16

Hello, A new question has been asked in "MariaDB Community" by TDS. Please answer it at http://mariadb.com/kb/en/aggregating-data-with-help-tables-will-raise-open-… as the person asking the question may not be subscribed to the mailing list. -------------------------------- Hello, I need some inspiration :-) Currently we have ~10 tables, each around 3 million rows and about 100 columns in MyISAM format. These table are only for writing data. A cronjob will aggregate data from these tables to time defined tables, e.g. min, hour, day, etc. And here is the problem: With CREATE TABLE and CREATE TEMPORARY TABLE there are difficulties. We create a table, read in data from main table, calculating values and write new data to time table. After that we delete the help table. But the table open cache gets bigger and bigger (>4000 in a day). So how can we avoid this? Switching to InnoDB or use another schema of aggregating values? -------------------------------- To view or answer this question please visit: http://mariadb.com/kb/en/aggregating-data-with-help-tables-will-raise-open-…

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[Maria-discuss] New Question: explanation of the salt statement
by AskMonty KB 04 Jul '16

04 Jul '16

Hello, A new question has been asked in "Encryption, Hashing and Compression Functions" by max-well_57049. Please answer it at http://mariadb.com/kb/en/explanation-of-the-salt-statement/ as the person asking the question may not be subscribed to the mailing list. -------------------------------- Hello together, I just saw the 'salt' Statement as I traces a login to MariaDB database. Could you explain me what this string is used for? -------------------------------- To view or answer this question please visit: http://mariadb.com/kb/en/explanation-of-the-salt-statement/

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[Maria-discuss] bootstrap okay but wsrep_cluster_size 0
by Umarzuki Mochlis 04 Jul '16

04 Jul '16

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[Maria-discuss] MariaDB 10.1.15 Released and Crash
by Alex 02 Jul '16

02 Jul '16

Hi, Last night one of my servers updated MariaDB to 10.1.15 and it started to crash every few minutes since the update ( from 10.1.14 -> 10.1.15 ). ------------ 160702 10:22:13 [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: 10.1.15-MariaDB key_buffer_size=268435456 read_buffer_size=524288 max_used_connections=8 max_threads=1001 thread_count=4 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 1804821 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x0x7f5a89876008 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 = 0x7f5ab5dd9058 thread_stack 0x48400 /usr/sbin/mysqld(my_print_stacktrace+0x2b)[0x7f5c9736641b] /usr/sbin/mysqld(handle_fatal_signal+0x475)[0x7f5c96ec29f5] /lib64/libpthread.so.0(+0xf7e0)[0x7f5c964c77e0] /usr/sbin/mysqld(_ZN10SQL_SELECT17test_quick_selectEP3THD6BitmapILj64EEyybbb+0x1fe5)[0x7f5c96fae535] /usr/sbin/mysqld(+0x49bb90)[0x7f5c96d92b90] /usr/sbin/mysqld(_ZN4JOIN14optimize_innerEv+0x1e2e)[0x7f5c96da1e9e] /usr/sbin/mysqld(_ZN4JOIN8optimizeEv+0x20)[0x7f5c96da2fe0] /usr/sbin/mysqld(_Z12mysql_selectP3THDPPP4ItemP10TABLE_LISTjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_select_lex+0x9d)[0x7f5c96da313d] /usr/sbin/mysqld(_Z13handle_selectP3THDP3LEXP13select_resultm+0x25d)[0x7f5c96da6add] /usr/sbin/mysqld(+0x451d52)[0x7f5c96d48d52] /usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0x5d7f)[0x7f5c96d5500f] /usr/sbin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x28d)[0x7f5c96d5854d] /usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x243b)[0x7f5c96d5b1ab] /usr/sbin/mysqld(_Z10do_commandP3THD+0x16b)[0x7f5c96d5b75b] /usr/sbin/mysqld(_Z26threadpool_process_requestP3THD+0xa7)[0x7f5c96e51777] mysys/stacktrace.c:247(my_print_stacktrace)[0x7f5c96e9c425] sql/signal_handler.cc:160(handle_fatal_signal)[0x7f5c964bfaa1] sql/opt_range.cc:12843(get_sel_arg_for_keypart)[0x7f5c949a4a8d] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (0x7f5aaf1b5020): is an invalid pointer Connection ID (thread ID): 456 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=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=off,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=off,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=off ------------ Anyone else encountered crashes on 10.1.15 ? Regards

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[Maria-discuss] New Question: statement metadata
by AskMonty KB 01 Jul '16

01 Jul '16

Hello, A new question has been asked in "Stored Programs and Views" by raphael.quadrini. Please answer it at http://mariadb.com/kb/en/statement-metadata/ as the person asking the question may not be subscribed to the mailing list. -------------------------------- Hi, Is there an equivalent function or stored procedure to Sql Server sys.dm_exec_describe_first_result_set? The goal is not to get the table or view metadata but the returned dataset metadata of a statement indead. thanks -------------------------------- To view or answer this question please visit: http://mariadb.com/kb/en/statement-metadata/

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[Maria-discuss] New Question: No of MariaDB Instances on MONyog
by AskMonty KB 01 Jul '16

01 Jul '16

Hello, A new question has been asked in "MariaDB FAQ" by palash.harchandani93_43595. Please answer it at http://mariadb.com/kb/en/no-of-mariadb-instances-on-monyog/ as the person asking the question may not be subscribed to the mailing list. -------------------------------- How many instances of mariadb can be installed with MONyog. If it depends on license please mention various licences and no of instances of types of licences. -------------------------------- To view or answer this question please visit: http://mariadb.com/kb/en/no-of-mariadb-instances-on-monyog/

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[Maria-discuss] New Question: MONyog version detection
by AskMonty KB 30 Jun '16

30 Jun '16

Hello, A new question has been asked in "MariaDB FAQ" by palash.harchandani93_43595. Please answer it at http://mariadb.com/kb/en/monyog-version-detection/ as the person asking the question may not be subscribed to the mailing list. -------------------------------- Is it possible to identify which version of MONyog is currently running when we are using the tarball installation?? This situation arises when I havent installed MONyog and I am a user who wwants to find which MONyog version is being used. -------------------------------- To view or answer this question please visit: http://mariadb.com/kb/en/monyog-version-detection/

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[Maria-discuss] New Question: Swap usage won't decrease
by AskMonty KB 28 Jun '16

28 Jun '16

Hello, A new question has been asked in "MariaDB FAQ" by alexandraarreaza. Please answer it at http://mariadb.com/kb/en/swap-usage-wont-decrease/ as the person asking the question may not be subscribed to the mailing list. -------------------------------- We have a 5 DB nodes Galera Cluster in Production (MariaDB 10.0). About a week ago a DB import was performed over an existing DB (Its size ~30G) and during this process, all DB nodes started complaining about swap usage and haven't stopped complaining since then (e.g: One of them would be using 814 MB out of 4095 MB). I have read a good few articles about MySQL and swapping issues (this is a good one: https://blog.jcole.us/2010/09/28/mysql-swap-insanity-and-the-numa-architect…) and also about swapping in MariaDB (https://mariadb.com/kb/en/mariadb/configuring-swappiness/) but still can't find out a way of solving this problem without restarting MySQL. We have NUMA architecture with 2 nodes and 96G of RAM. Our buffer pool size is 70G and it is set to use 12 innodb_buffer_pool_instances. 1) Is there any fix to this situation besides restarting MySQL? 2) Is there a way of tuning our cluster to avoid swapping in the future? Thanks. -------------------------------- To view or answer this question please visit: http://mariadb.com/kb/en/swap-usage-wont-decrease/

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[Maria-discuss] columnstore
by Roberto Spadim 28 Jun '16

28 Jun '16

Hi guys! anyone testing columnstore? i will test in a SCADA system this week, news and problems i will report here -- Roberto Spadim

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