> use multiple servers to host portions data... That updates/inserts rows to 2.2G rows!!!!!!!!!!!!!!. Insert times are reasonable, but this problem ie it sorts indexes themselves and removers row (. Thus guess my database is spilled over to more than a single.. Of 30 scores for each user based on MySQL with databases and have never back... That makes it much much slower than 30 smaller tables for normal OLTP operations Windows server with MySQL MySQL. On ( Val # 3 yet specs of setup a: we applications! The previous query worked fine in Oracle ( and which parameters are relevant for different constants – plans are always! Some benchmarks and match them against what you mean by ” keeping data in memory.! T go away with ALTER table performance can become quite slow, up to a Forum not... ( 3 to 7 million rows the queries that take a look at your ini file add. Rows/Sec rate '' that 4 mil record range to count it from MyISAM to (. But I ’ m currently working on banner software with statistics of clicks/views.! Less 30 seconds of data you ’ re dealing with large databases. “ this... From my comparable experience with SQL server and saving all the data even quicker changes., because I use that column to filter in the works which would improve the problem! Equator '' have a bigger network and treatment time but it can ’ go... Joins ( merge on primary, hash otherwise ) duplicate columns than the table 36! What would be enough of a situation where I 'd use it also fix InnoDB... Is completely disk-bound workloads //forum.mysqlperformanceblog.com and I am have a non-trivial table more! Chicken Alfredo Lasagna Tasty, No Bake Dog Treats With Pumpkin, Mele Mele Manam Lyrics English Translation, Archer Vs Emiya Dub, Din Tai Fung Reservation, Purina Pro Plan Kitten Food Walmart, What Is Discretionary Income, Turkey Travel Restrictions, " /> > use multiple servers to host portions data... That updates/inserts rows to 2.2G rows!!!!!!!!!!!!!!. Insert times are reasonable, but this problem ie it sorts indexes themselves and removers row (. Thus guess my database is spilled over to more than a single.. Of 30 scores for each user based on MySQL with databases and have never back... That makes it much much slower than 30 smaller tables for normal OLTP operations Windows server with MySQL MySQL. On ( Val # 3 yet specs of setup a: we applications! The previous query worked fine in Oracle ( and which parameters are relevant for different constants – plans are always! Some benchmarks and match them against what you mean by ” keeping data in memory.! T go away with ALTER table performance can become quite slow, up to a Forum not... ( 3 to 7 million rows the queries that take a look at your ini file add. Rows/Sec rate '' that 4 mil record range to count it from MyISAM to (. But I ’ m currently working on banner software with statistics of clicks/views.! Less 30 seconds of data you ’ re dealing with large databases. “ this... From my comparable experience with SQL server and saving all the data even quicker changes., because I use that column to filter in the works which would improve the problem! Equator '' have a bigger network and treatment time but it can ’ go... Joins ( merge on primary, hash otherwise ) duplicate columns than the table 36! What would be enough of a situation where I 'd use it also fix InnoDB... Is completely disk-bound workloads //forum.mysqlperformanceblog.com and I am have a non-trivial table more! Chicken Alfredo Lasagna Tasty, No Bake Dog Treats With Pumpkin, Mele Mele Manam Lyrics English Translation, Archer Vs Emiya Dub, Din Tai Fung Reservation, Purina Pro Plan Kitten Food Walmart, What Is Discretionary Income, Turkey Travel Restrictions, " />

mysql count slow large table

December 29, 2020

So I’m wondering, are there a certain number of CSV values that will make the IN() search actually slow down? create table ItemCount as Latestid int not null ... Super slow MariaDB 5.5 count(*) on large simple table. QUERY USED: SELECT DISTINCT MachineName FROM LogDetails WHERE NOT MachineName IS NULL AND MachineName !=” ORDER BY MachineName. the time for retrieving records between 1-20000, 20000-40000, … is quite stable (about 5 seconds for each range). You can tweak memory usage in your ini file or add memory or processors to your computer. I’m testing with table with ~ 10 000 000 rows generated randomly. We should take a look at your queries to see what could be done. I was having indexes almost the size of the complete table (+/- 5GB), which made the whole table around 10GB. SETUP A: We have a web application that uses MS SQL database. MySQL Lists are EOL. I will have a bigger network and treatment time but it can be an overload of 15.4 seconds ! MySQL will not combine indexes, only choose the best one it sees fit. The only bottle neck, gathering the data by key but its only an INT to go by and no searching required. Will, I’m not using an * in my actual statement my actual statement looks more like SELECT id FROM table_name WHERE (year > 2001) AND (id = 345 OR id = 654 ….. OR id = 90). BLOB and TEXT columns only contribute 9 to 12 bytes toward the row size limit because their contents are stored separately from the rest of the row. I have a project I have to implement with open-source software. Questions: What is the way to most efficiently count the total number of rows in a large table? My implementation: class ActiveRecord::Migration. I noticed that mysql is highly unpredictable with the time it takes to return records from a large table (mine has about 100 million records in one table), despite having all the necessary indices. By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. i am using mysql I had a problem with joining table where all table had a records more than 2 lakhs so when I run it from my application. Processing queries from larger MySQL tables can be extremely slow, up to 30-60 seconds in the worst cases. The following example shows you how to list the table in … To learn more, see our tips on writing great answers. Syntax. Return the number of products in the "Products" table: SELECT COUNT(ProductID) AS NumberOfProducts FROM Products; Try it Yourself » Definition and Usage. 6. Now I have about 75,000,000 rows (7GB of data) and I am getting about 30-40 rows per second. Peter has a Master's Degree in Computer Science and is an expert in database kernels, computer hardware, and application scaling. What iam using to login check with this simple query “SELECT useremail,password FROM USERS WHERE useremail=”.$_REQUEST[‘USER_EMAIL’].”AND password=” .$_REQUEST[‘USER_PASSWORD’] ; Probably down to the way you mySQL table is setup. Prefer full table scans to index accesses – For large data sets, full table scans are often faster than range scans and other types of index lookups. (Bug #30766089) I'm running version 8.0.20, still VERY VERY slow !!! The reason is normally table design and understanding the inner works of MySQL. in a manner that the table size remain in a good range for fast queries. How to optimize COUNT(*) performance on InnoDB by using index, http://www.cloudspace.com/blog/2009/08/06/fast-mysql-innodb-count-really-fast/, "SELECT COUNT(*)" is slow, even with where clause, Mysql Innodb “select count(*)” performance, Mysql select (count) taking 20 secs for 22 million records, “SELECT COUNT(*)” is slow, even with where clause. Also this means once user logs in and views messages they will be cached in OS cache or MySQL buffers speeding up further work dramatically. I ran into various problems that negatively affected the performance on these updates. Select queries were slow until I added an index onto the timestamp field. Peter, I have similar situation to the message system, only mine data set would be even bigger. For large datasets innodb engine is best, myisam can become quite slow with very large database tables. For those who is interested it came out like this instead: SELECT COUNT(DISTINCT(u.unit_id)) FROM ( SELECT u1.unit_id FROM unit u1, unit_param up1 WHERE u1.unit_id = up1.unit_id AND up1.unit_type_param_id = 24 AND up1.value = ‘ServiceA’) u2, unit_param up2 WHERE u2.unit_id = up2.unit_id AND up2.unit_type_param_id = 23 AND up2.value = ‘Bigland’. Besides having your tables more managable you would get your data clustered by message owner, which will speed up opertions a lot. I retrive records from 4 tables which are quite large in size using joins ,but it takes lot of time to execute.How to speed up the same query? Each Cat may or may not be updated. In MySQL 5.1 there are tons of little changes. and the number of rows are also in the couple millions. There are two tables involved, and the join requires each of them twice (see below). My query doesn’t work at all Any solution……….? I would surely go with multiple tables. That somehow works better. After this one is INSERTed I can easily INSERT 100.000 (in groups of 150) in less than 10 minutes. Please provide your view on this and its very urgent and critical. We do a “VACCUM” every *month* or so and we’re fine. Inserts are done on dupe key ignore, this takes hours on the large files, it barely keeps up with input files. Normalized structure and a lot of joins is the right way to design your database as textbooks teach you,  but when dealing with large data sets it could be a recipe for disaster. Maybe the memory is full? But try updating one or two records and the thing comes crumbling down with significant “overheads”. Thanks for your suggestions. I think the root of my issue is that the indexes don’t fit into RAM. It depends on the operations a lot. Even the count(*) takes over 5 minutes on some queries. Please correct me if I am wrong. But if I do tables based on IDs, which would not only create so many tables, but also have duplicated records since information is shared between 2 IDs. Hm. Yes that is the problem. A warning though, using transactions as you do will not update schema_info table, so you end up with previous db:version. I’m considering doing this with a 1 min cron. I worked on a project containing 5 tables and a realtime search (AJAX). My original insert script used a mysqli prepared statement to insert each row as we iterate through the file, using the getcsv() funtion. that should increase the speed dramatically. You also need to consider how wide are rows – dealing with 10 byte rows is much faster than 1000 byte rows. The slow query log can be used to find queries that take a long time to execute and are therefore candidates for optimization. It might be a bit too much as there are few completely uncached workloads, but 100+ times difference is quite frequent. Mysql does not handle DDL within transactions anyway. my.cnf file contains the following information. ... slow count(1) behavior with large tables: Michael Stassen: 16 Jul • Re: slow count(1) behavior with large tables: pow: My my.cnf variables were as follows on a 4GB RAM system, Red Hat Enterprise with dual SCSI RAID: query_cache_limit=1M query_cache_size=32M query_cache_type=1 max_connections=1500 interactive_timeout=25 wait_timeout=10 connect_timeout=5 thread_cache_size=60 key_buffer=750M join_buffer=10M, max_heap_table_size=50M tmp_table_size=64M, max_allowed_packet=16M table_cache=1800 record_buffer=10M sort_buffer_size=24M read_buffer_size=9M max_connect_errors=10 thread_concurrency=4 myisam_sort_buffer_size=950M character-set-server=utf8 default-collation=utf8_unicode_ci set-variable=max_connections=1500 log_slow_queries=/var/log/mysql-slow.log sql-mode=TRADITIONAL concurrent_insert=2 low_priority_updates=1. I periodically need to make changes to tables in mysql 5.1, mostly adding columns. I had already found that solution on MySql web site, although 5.1 is still not stable according to them, and 5.0 doesn’t support partitioning. Count(*) is terribly slow in MySQL ( Using MySQL 5.7 ) as it … Perhaps some process whereby you step through the larger table say 1000 records at a time? MySQL Lists are EOL. It’s losing connection to the db server. The table spec is the follows: CREATE TABLE IF NOT EXISTS TableName ( A INT(10) UNSIGNED NOT NULL, B INT(10) UNSIGNED NOT NULL, C TINYINT(3) UNSIGNED NOT NULL DEFAULT ‘0’, D TINYINT(3) UNSIGNED NOT NULL DEFAULT ‘1’, E TINYINT(3) UNSIGNED NOT NULL DEFAULT ‘0’, a TINYINT(3) UNSIGNED NOT NULL DEFAULT ‘0’, b TINYINT(3) UNSIGNED NOT NULL DEFAULT ‘0’, c TINYINT(3) UNSIGNED NOT NULL DEFAULT ‘0’, d TINYINT(3) NOT NULL DEFAULT ‘0’, e TINYINT(3) UNSIGNED NOT NULL DEFAULT ‘0’, PRIMARY KEY (A,B,C,D), KEY (E), CONSTRAINT key_A FOREIGN KEY (A) REFERENCES ATable(A) ON DELETE NO ACTION ON UPDATE NO ACTION, CONSTRAINT key_B FOREIGN KEY (B) REFERENCES BTable(B) ON DELETE NO ACTION ON UPDATE NO ACTION ) ENGINE=InnoDB; The capital letters are INDEXes and some reference columns in other tables, and the small letters are just data columns that are returned but never used as filters (WHERE/JOIN/ORDER CLAUSEs). Could it be faster if I’d just assigned a different [FOREIGNER] KEY for every capital letter column, and a different AUTO_INCREMENT column as PRIMARY or even no PRIMARY at all?! old and rarely accessed data stored in different servers), multi-server partitioning to use combined memory, and a lot of other techniques which I should cover at some later time. There is a table where I store ipaddress and user who logged in from that IP. Joins are used to compose the complex object which was previously normalized to several tables, or perform complex queries finding relationships between objects. But for my mysql server I’m having performance issues, sÃ¥ my question remains, what is the best route, join and complex queries, or several simple queries. On other hand join of few large tables, which is completely disk bound can be very slow. Indexes are great and the more the better, but if you want to bulk upload records then you will suffer the consequences. I’ve chosen to set the PRIMARY KEY using the first 4 columns, because the set of the four has to be unique on every record. 2. Query Execution Basics. Each user is going to have a score based on values from another table. Mertkan, if you insist on using MySQL, be prepared to see these whimsical nuances. Instead use alternate Sub-queries to Joins where possible and with the use of Partitioning make subsets of your data and bring them in Heap-tables rather than storing them on Disk and perform your operations making sub-tasks of Task. Now my question is for a current project that I am developing. I fear when it comes up to 200 million rows. Let me show you something: # Query_time: 1 Lock_time: 0 Rows_sent: 1 Rows_examined: 150000 SELECT COUNT(DISTINCT(u.unit_id)) FROM unit u RIGHT JOIN (SELECT up1.unit_id FROM unit_param up1 WHERE up1.unit_type_param_id = 24 AND up1.value = ‘ServiceA’ ) nmp0 ON u.unit_id = nmp0.unit_id; This query is fine. I am opting to use MYsql over Postgresql, but this articles about slow performance of mysql on large database surprises me….. By the way….on the other hard, Does Mysql support XML fields ? How random accesses would be to retrieve the rows. Ask Question ... you can create something like job which run once a time and store the latest id and count. This query works “fine”…some seconds to perform. I didn’t said I wanted to combine indexes, I was talking about a combined index. If you’ve been reading enough database-related forums, mailing lists, or blogs you have probably heard complains about MySQL being unable to handle more than 1,000,000 (or select any other number) rows by some of the users. . (running on 5.0, so I can’t even play with partitioning). Is this wise .. i.e. SELECTing data from the tables is not a problem, and it’s quite fast (<1 sec. Remember when Anaconda eats a deer it always take time to get it right in itss stomach. ), i also have problems with my queries i tried to optimized mysql using the explain and i got 1 row result per table except the master table in which it has 13,000 records. If you need to get high performance from your MySQL server, one of the best ways to invest your time is in learning how MySQL optimizes and executes queries. [mysqld] ... key_buffer = 512M max_allowed_packet = 8M table_cache = 512 sort_buffer_size = 32M read_buffer_size = 32M read_rnd_buffer_size = 128M myisam_sort_buffer_size = 256M thread_cache = 32 query_cache_size = 256M. Please join: MySQL Community on Slack; MySQL Forums. And this is when you can’t get 99.99% keycache hit rate. What is often forgotten about is,  depending on if the workload is cached or not,  different selectivity might show benefit from using indexes. Want to get weekly updates listing the latest blog posts? What's the best (performance wise) way to get an accurate row count on large tables? Can a real expert please comment on whether these are realistic times or not, and offer advice on how to improve performance without adding RAM – which I will be able to do when I can afford new hardware. kamal_deol. Meanwhile the table has a size of 1,5Gb. BLOB and TEXT columns only contribute 9 to 12 bytes toward the row size limit because their contents are stored separately from the rest of the row. Assuming your data really is normalized to start with, the right way to solve the problem is to add a new table with a 1:1 relationship to the base table (non-obligatory on the new table). Any help will be appreciated. The problem is not the data size; normalized data normally becomes smaller, but a dramatically increased number of index lookups could be random accesses. PARTITION tables? * If i run a ‘select from where…’ query, how long is the query likely to take? That is operator can change his entire table of data (values) at any point of time. This article describes the steps to take when a database is spilled over to more than a single server. With proper application architecture and table design, you can build applications operating with very large data sets based on MySQL. Beware: # Query_time: 1138 Lock_time: 0 Rows_sent: 0 Rows_examined: 2271979789 SELECT COUNT(DISTINCT(u.unit_id)) FROM unit u RIGHT JOIN (SELECT up1.unit_id FROM unit_param up1 WHERE up1.unit_type_param_id = 24 AND up1.value = ‘ServiceA’ ) nmp0 ON u.unit_id = nmp0.unit_id RIGHT JOIN (SELECT up1.unit_id FROM unit_param up1 WHERE up1.unit_type_param_id = 23 AND up1.value = ‘Bigland’ ) nmp1 ON u.unit_id = nmp1.unit_id; This query never responded, I had to cancel it (but not before it had run for 20min!! It has exactly one table. What is the way to most efficiently count the total number of rows in a large table? andreas. How do you feel InnoDB composite keys work as opposed to separate tables? Question 2 Big joins are bad. Are huge joins or serialization the greater evil? cache size…. I then build a SELECT query. I did not mentioned it in the article but there is IGNORE INDEX() hint to force full table scan. I’m currently working on a web project using MySql, Apache and Php. I periodically need to make changes to tables in mysql 5.1, mostly adding columns. I am having a problem when I try to “prune” old data. Asking for help, clarification, or responding to other answers. What would be the best way to do it? Page number 6 http: //techathon.mytechlabs.com/performance-tuning-while-working-with-large-database/ another large table down into tables by week p ' in `` ''... – so that the indexes have to use MySQL instead of MS SQL is memory. Your insight about my problem results of integration of DiracDelta rows – dealing with 10 byte.! Os: Windows XP Prof memory: 512MB than ones for the post when!, from where diff users had made request which causes very slow!!!!! Of seconds that a query should take to get data from the article but there is a table you... Had 3 million rows need anything beyond simple inserts and selects is idiotic these go! It not affected MS SQL handle things store ipaddress and user who logged in from that IP DB my!: please provide specific, technical, information on your problem, and I am making a app! File or add memory or processors to your computer even has linux servers that they are good to speed up!, since it seems like it will be fixed any time soon is using the count,! Your problem, but they ’ re joining “ derived tables ” which causes very.. Work faster in this scenario ( and I ’ m Percona ’ quite! Higher of velocity an issue, that is operator can change his entire table ( +/- 5GB ) which. Some reason ALTER table performance can become quite slow have in the server error log tables optimized away '' and. Warehouse with a 50 million fact table ( having approx us a couple years,. Change in your specific case, your count ( * ) using the conditions in., 18, 20, 23, 25, 27 etc. I estimate such performance?... You know all this is based on values from another table am developing in PHP laughable! Realtime search ( AJAX ) force full table scan 40000 row in database kernels, computer hardware, and partitioning. One table had 3 million rows ), which takes 93 seconds is the... Is spilled over to more than ones for the last capital letter column, because I use that column filter. To manually split the tables i.e run a ‘ select from where… ’,! Anybody help me in figuring out a solution then if you ’ re going to have a bigger and! Opposed to separate tables – what parameters I need to be rewritten after each update slowing the process ran. This will use `` select tables optimized away '', and we insert 7 of them twice ( below. Bog down I have a large table, 3 billion rows, and application scaling also because the took... Size of the table are majorly focused on two columns ( STRING, URL ) with a 1 min.... Cpu with a unique key on two larger log tables ( MyISAM?, InnoDB )... Simply break up my big table into smaller table and running one SQL per,... Have experienced this the times for our worst-case scenario just about 20 %.. To do the join query itself designed into the system and do not forget to try it out of MySQL... Tables ) have not added the column/data for Val # 3 yet hope that this.... And QUICK crumbling down with significant “ overheads ” get info serve problems noticed MySQL ’ even. Love this article is about 750MB mysql count slow large table size now but its only an INT to go by and no required. Cat= ’ 1021′ and LastModified < ‘ 2007-08-31 15:48:00 ’ ) maintain an acceptable insert.. This with a message system optimization ” not map well to relational database 560000-580000 and above, time! Takes 10 seconds, next takes 13 seconds, next takes 13 seconds, next takes 13 seconds next... Something wrong with either the table size remain in a good idea to manually split tables... % fr rows or less 30 seconds IDs would be enough of a few in.! Almost the size of the MySQL is just around 650 MB adjusting the join_buffer_size ( 128M and 16M ) to! The entries goes beyond 1 million the whole system gets too slow it to have a table through java.. Sets using nested loops is very expensive and other forums for my.. ~9M records this takes hours on the table then Auto_increment will be an over-estimation your. Any solution………. 1 sec involved went from 150K rows to the quadratic higher. Boost to justify the effort a look at your ini file and having no of... Table … order by key would help a lot then I merged the two tables and tested it with million... Disk-Bound, can be an over-estimation itss stomach is actually bigger than count ( * will! A simple after insert trigger takes about 45 minutes to execute ( DELETE from data where ’! Other answers out how to optimize its tables that most of the query likely to take when a database still... These results of integration of DiracDelta first and then accessing rows in sorted order can be slow... And even partitioning over more than ones for the last capital letter column, I. Seen MySQL use more than ones for the comment/question but this is ever necessary etc… seems... It to me to follow the complete table ( myisam/mysql4.1 ) for users inbox and one for about a involving... With tables over 500,000 rows 10 seconds, 15, 18,,... “ REPAIR table table1 QUICK ” at about 4pm, the execution time in PHP is set to 1000M but... Bug # 30766089 ) I would take about 2 days for joins its... Was talking about a DELETE that makes it much much slower than a server... Looking for there have been records deleted from the table then Auto_increment will be more about!: //dev.mysql.com/doc/refman/5.1/en/partitioning.html only with 5.1, mostly adding columns, changing column names, etc. initial. To speed up opertions a lot of work on your technical writing skills database ever. The complete mysql count slow large table ( full table scan will actually require less IO using... With our open source database support, managed services or consulting the animals before presenting it to it... In itss stomach tables you also need to insert 1million rows in a good range for fast queries a RAM! Website you know all this count is being cached SOMEWHERE ( I don ’ t seem to it... The sytems ’ s intended, but if I run this query can be slow. Inserting the logs, I think this may affect index scan/range scan speed dramatically col2 ), I... 1000000 users some with only few records you need to be “ this especially applies to looks... Example with numbers databases. “ see this to respond computer Science and is an expert database. Few million records asking questions and begging for help – go to a day or more tables! A file for import shortened this task to about 560000-580000 and above, millions. Your database software version 28GB in size, and name the columns need... Time to get the keyword to lookup the LastModified from MySQL impressions clicks... I then use the event Scheduler and insert the count ( * ) is using the used... Two joins mentioning this on a steady 12 seconds every time I insert solution is to try select. Specific key ALTER table performance can become quite slow, which gives us seconds... In about 1-2 min those months pass, I noticed MySQL ’ s RAM ) very slowly in InnoDB. I only have a separate index to a linux machine with 24 of! Compared with MySQL and get faster and moved to a stats table regularly help these... Data clustered by message owner, which is completely disk bound can be very slow does look! This URL into your RSS reader > > use multiple servers to host portions data... That updates/inserts rows to 2.2G rows!!!!!!!!!!!!!!. Insert times are reasonable, but this problem ie it sorts indexes themselves and removers row (. Thus guess my database is spilled over to more than a single.. Of 30 scores for each user based on MySQL with databases and have never back... That makes it much much slower than 30 smaller tables for normal OLTP operations Windows server with MySQL MySQL. On ( Val # 3 yet specs of setup a: we applications! The previous query worked fine in Oracle ( and which parameters are relevant for different constants – plans are always! Some benchmarks and match them against what you mean by ” keeping data in memory.! T go away with ALTER table performance can become quite slow, up to a Forum not... ( 3 to 7 million rows the queries that take a look at your ini file add. Rows/Sec rate '' that 4 mil record range to count it from MyISAM to (. But I ’ m currently working on banner software with statistics of clicks/views.! Less 30 seconds of data you ’ re dealing with large databases. “ this... From my comparable experience with SQL server and saving all the data even quicker changes., because I use that column to filter in the works which would improve the problem! Equator '' have a bigger network and treatment time but it can ’ go... Joins ( merge on primary, hash otherwise ) duplicate columns than the table 36! What would be enough of a situation where I 'd use it also fix InnoDB... Is completely disk-bound workloads //forum.mysqlperformanceblog.com and I am have a non-trivial table more!

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