When you're inserting records, the database needs to update the indexes on every insert, which is costly in terms of performance. max_connect_errors=10 Hi. single large operation. If you're inserting into a table in large dense bursts, it may need to take some time for housekeeping, e.g. for tips specific to MyISAM tables. I am running MYSQL 5.0. Improve INSERT-per-second performance of SQLite, Insert into a MySQL table or update if exists. How random accesses would be to retrieve the rows. Monitor the health of your database infrastructure, explore new patterns in behavior, and improve the performance of your databases no matter where theyre located. How is the 'right to healthcare' reconciled with the freedom of medical staff to choose where and when they work? Now my question is for a current project that I am developing. concurrent_insert=2 Integrity checks dont work try making a check on a column NOT NULL to include NOT EMPTY (i.e., no blank space can be entered, which as you know, is different from NULL). Hm. Use multiple servers to host portions of the data set. oh.. one tip for your readers.. always run explain on a fully loaded database to make sure your indexes are being used. On a personal note, I used ZFS, which should be highly reliable, I created Raid X, which is similar to raid 5, and I had a corrupt drive. Also consider the innodb plugin and compression, this will make your innodb_buffer_pool go further. Consider deleting the foreign key if insert speed is critical unless you absolutely must have those checks in place. Does this look like a performance nightmare waiting to happen? Each row consists of 2x 64 bit integers. A single source for documentation on all of Perconas leading, this Manual, Block Nested-Loop and Batched Key Access Joins, Optimizing Subqueries, Derived Tables, View References, and Common Table They can affect insert performance if the database is used for reading other data while writing. This is fairly common on a busy table, or if your server is executing long/complex transactions. table_cache=1800 There are also some periodic background tasks that can occasionally slow down an insert or two over the course of a day. In specific scenarios where we care more about data integrity thats a good thing, but if we upload from a file and can always re-upload in case something happened, we are losing speed. Q.question, The above example is based on one very simple website. QAX.questionid, Speaking about table per user it does not mean you will run out of file descriptors. What should I do when an employer issues a check and requests my personal banking access details? I filled the tables with 200,000 records and my query wont even run. It can easily hurt overall system performance by trashing OS disk cache, and if we compare table scan on data cached by OS and index scan on keys cached by MySQL, table scan uses more CPU (because of syscall overhead and possible context switches due to syscalls). My problem is some of my queries take up to 5 minutes and I cant seem to put my finger on the problem. Can splitting single 100G file into "smaller" files help? MySQL inserts with a transaction Changing the commit mechanism innodb_flush_log_at_trx_commit=1 innodb_flush_log_at_trx_commit=0 innodb_flush_log_at_trx_commit=2 innodb_flush_log_at_timeout Using precalculated primary key for string Changing the Database's flush method Using file system compression Do you need that index? A.answername, Sometimes overly broad business requirements need to be re-evaluated in the face of technical hurdles. (b) Make (hashcode,active) the primary key - and insert data in sorted order. As you probably seen from the article my first advice is to try to get your data to fit in cache. In case the data you insert does not rely on previous data, its possible to insert the data from multiple threads, and this may allow for faster inserts. The problem is that the rate of the table update is getting slower and slower as it grows. (Tenured faculty). The transaction log is needed in case of a power outage or any kind of other failure. After we do an insert, it goes to a transaction log, and from there its committed and flushed to the disk, which means that we have our data written two times, once to the transaction log and once to the actual MySQL table. How do I rename a MySQL database (change schema name)? The index does make it very fast for one of my table on another project (list of all cities in the world: 3 million rows). Lets do some computations again. I've written a program that does a large INSERT in batches of 100,000 and shows its progress. Also do not forget to try it out for different constants plans are not always the same. LEFT JOIN (tblevalanswerresults e1 INNER JOIN tblevaluations e2 ON Here's the log of how long each batch of 100k takes to import. Yes. In fact it is not smart enough. (In terms of Software and hardware configuration). There are 277259 rows and only some inserts are slow (rare). if a table scan is preferable when doing a range select, why doesnt the optimizer choose to do this in the first place? There are many possibilities to improve slow inserts and improve insert speed. A.answername, How do I rename a MySQL database (change schema name)? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Ok, here are specifics from one system. How can I detect when a signal becomes noisy? Unfortunately, with all the optimizations I discussed, I had to create my own solution, a custom database tailored just for my needs, which can do 300,000 concurrent inserts per second without degradation. Consider a table which has 100-byte rows. Decrease number of joins in your query, instead forcing the DB, use java streams for filtering, aggregating and transformation. Mysql improve query speed involving multiple tables, MySQL slow query request fix, overwrite to boost the speed, Mysql Query Optimizer behaviour not consistent. This is a very simple and quick process, mostly executed in main memory. Its possible to allocate many VPSs on the same server, with each VPS isolated from the others. MYISAM table with the following activity: 1. Not to mention keycache rate is only part of the problem you also need to read rows which might be much larger and so not so well cached. set long_query . All of Perconas open-source software products, in one place, to Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community. As an example, in a basic config using MyISM tables I am able to insert 1million rows in about 1-2 min. The box has 2GB of RAM, it has dual 2.8GHz Xeon processors, and /etc/my.cnf file looks like this. Joins to smaller tables is OK but you might want to preload them to memory before join so there is no random IO needed to populate the caches. You can use the following methods to speed up inserts: If you are inserting many rows from the same client at the same time, use INSERT statements with multiple VALUES lists to insert several rows at a time. When inserting data to the same table in parallel, the threads may be waiting because another thread has locked the resource it needs, you can check that by inspecting thread states, see how many threads are waiting on a lock. It can be happening due to wrong configuration (ie too small myisam_max_sort_file_size or myisam_max_extra_sort_file_size) or We will see. You however want to keep value hight in such configuration to avoid constant table reopens. What everyone knows about indexes is the fact that they are good to speed up access to the database. Here's the EXPLAIN output. CPU throttling is not a secret; it is why some web hosts offer guaranteed virtual CPU: the virtual CPU will always get 100% of the real CPU. The difference is 10,000 times for our worst-case scenario. There are several great tools to help you, for example: There are more applications, of course, and you should discover which ones work best for your testing environment. Add a SET updated_at=now() at the end and you're done. The parity method allows restoring the RAID array if any drive crashes, even if its the parity drive. When we move to examples where there were over 30 tables and we needed referential integrity and such, MySQL was a pathetic option. After 26 million rows with this option on, it suddenly takes 520 seconds to insert the next 1 million rows.. Any idea why? Maybe the memory is full? Hi again, Indeed, this article is about common misconfgigurations that people make .. including me .. Im used to ms sql server which out of the box is extremely fast .. Sergey, Would you mind posting your case on our forums instead at What are possible reasons a sound may be continually clicking (low amplitude, no sudden changes in amplitude). Just do not forget about the performance implications designed into the system and do not expect joins to be free. Having too many connections can put a strain on the available memory. Runing explain is good idea. The REPLACE ensure that any duplicate value is overwritten with the new values. 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. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. And the last possible reason - your database server is out of resources, be it memory or CPU or network i/o. previously dumped as mysqldump tab), The data was some 1.3G, 15.000.000 rows, 512MB memory one the box. ALTER TABLE normally rebuilds indexes by sort, so does LOAD DATA INFILE (Assuming were speaking about MyISAM table) so such difference is quite unexpected. PRIMARY KEY (ID), So we would go from 5 minutes to almost 4 days if we need to do the join. Also, is it an option to split this big table in 10 smaller tables ? How can I speed it up? General InnoDB tuning tips: The large offsets can have this effect. Innodb's ibdata file has grown to 107 GB. A unified experience for developers and database administrators to This article is BS. In some cases, you dont want ACID and can remove part of it for better performance. The first 1 million records inserted in 8 minutes. sent items is the half. Normally MySQL is rather fast loading data in MyISAM table, but there is exception, which is when it cant rebuild indexes by sort but builds them sql 10s. Although its for read and not insert it shows theres a different type of processing involved. Can we create two different filesystems on a single partition? Dont recommend REPLACE INTO, its asinine. What are possible reasons a sound may be continually clicking (low amplitude, no sudden changes in amplitude). Will, e1.evalid = e2.evalid As we saw my 30mil rows (12GB) table was scanned in less than 5 minutes. Can someone please tell me what is written on this score? row by row instead. 1. show variables like 'slow_query_log'; . Not the answer you're looking for? What kind of tool do I need to change my bottom bracket? You can use the following methods to speed up inserts: If you are inserting many rows from the same client at the same time, use INSERT statements with multiple VALUES lists to insert several rows at a time. Fortunately, it was test data, so it was nothing serious. Check every index if its needed, and try to use as few as possible. ASAX.answerid, monitor, manage, secure, and optimize database environments on any This is incorrect. The flag innodb_flush_method specifies how MySQL will flush the data, and the default is O_SYNC, which means all the data is also cached in the OS IO cache. Once partitioning is done, all of your queries to the partitioned table must contain the partition_key in the WHERE clause otherwise, it will be a full table scan which is equivalent to a linear search on the whole table. When using prepared statements, you can cache that parse and plan to avoid calculating it again, but you need to measure your use case to see if it improves performance. If you are adding data to a nonempty table, you can tune the bulk_insert_buffer_size variable to make data insertion even faster. When loading a table from a text file, use Q.questioncatid, I used MySQL with other 100.000 of files opened at the same time with no problems. Its free and easy to use). It has exactly one table. send the data for many new rows at once, and delay all index Im doing the following to optimize the inserts: 1) LOAD DATA CONCURRENT LOCAL INFILE '/TempDBFile.db' IGNORE INTO TABLE TableName FIELDS TERMINATED BY '\r'; Peter, The problem becomes worse if we use the URL itself as a primary key, which can be one byte to 1024 bytes long (and even more). In case there are multiple indexes, they will impact insert performance even more. This means the database is composed of multiple servers (each server is called a node), which allows for faster insert rate The downside, though, is that its harder to manage and costs more money. MySQL supports two storage engines: MyISAM and InnoDB table type. Insert ignore will not insert the row in case the primary key already exists; this removes the need to do a select before insert. Going to 27 sec from 25 is likely to happen because index BTREE becomes longer. Note: multiple drives do not really help a lot as were speaking about single thread/query here. I was able to optimize the MySQL performance, so the sustained insert rate was kept around the 100GB mark, but thats it. I have tried indexes and that doesnt seem to be the problem. Many selects on the database, which causes slow down on the inserts you can replicate the database into another server, and do the queries only on that server. After that, records #1.2m - #1.3m alone took 7 mins. My query is based on keywords. Depending on type of joins they may be slow in MySQL or may work well. I understand that I can unsubscribe from the communication at any time in accordance with the Percona Privacy Policy. A simple AFTER INSERT trigger takes about 7 second. There are 277259 rows and only some inserts are slow (rare). COUNT(DISTINCT e1.evalanswerID) AS totalforinstructor, I have a table with 35 mil records. Thanks for your hint with innodb optimizations. 2. There is no need for the temporary table. This means that InnoDB must read pages in during inserts (depending on the distribution of your new rows' index values). Having multiple pools allows for better concurrency control and means that each pool is shared by fewer connections and incurs less locking. You also need to consider how wide are rows dealing with 10 byte rows is much faster than 1000 byte rows. Im working on a project which will need some tables with about 200-300 million rows. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. LEFT JOIN (tblevalanswerresults e3 INNER JOIN tblevaluations e4 ON With this option, MySQL flushes the transaction to OS buffers, and from the buffers, it flushes to the disk at each interval that will be the fastest. They have many little sections in their website you know. It is likely that you've got the table to a size where its indexes (or the whole lot) no longer fits in memory. (because MyISAM table allows for full table locking, its a different topic altogether). Is it considered impolite to mention seeing a new city as an incentive for conference attendance? By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Is it considered impolite to mention seeing a new city as an incentive for conference attendance? Replacing a 32-bit loop counter with 64-bit introduces crazy performance deviations with _mm_popcnt_u64 on Intel CPUs, What to do during Summer? e1.evalid = e2.evalid This could be done by data partitioning (i.e. So when I would REPAIR TABLE table1 QUICK at about 4pm, the above query would execute in 0.00 seconds. MySQL supports table partitions, which means the table is split into X mini tables (the DBA controls X). For a regular heap tablewhich has no particular row orderthe database can take any table block that has enough free space. http://tokutek.com/downloads/tokudb-performance-brief.pdf, Increase from innodb_log_file_size = 50M to ASAX.answersetid, REPLACE INTO is asinine because it deletes the record first, then inserts the new one. I think you can give me some advise. How do I import an SQL file using the command line in MySQL? I found that setting delay_key_write to 1 on the table stops this from happening. Making any changes on this application are likely to introduce new performance problems for your users, so you want to be really careful here. Were using LAMP. Im writing about working with large data sets, these are then your tables and your working set do not fit in memory. val column in this table has 10000 distinct value, so range 1..100 selects about 1% of the table. Innodb configuration parameters are as follows. Adding a new row to a table involves several steps. INNER JOIN tblanswersetsanswers_x ASAX USING (answersetid) This is the case then full table scan will actually require less IO than using indexes. But this isn't AFAIK the cause, of the slow insert query? Simply passing all the records to the database is extremely slow as you mentioned, so use the speed of the Alteryx engine to your advantage. query_cache_size=32M InnoDB is suggested as an alternative. This especially applies to index lookups and joins which we cover later. How much index is fragmented ? Alteryx only solution. The best way is to keep the same connection open as long as possible. Increase Long_query_time, which defaults to 10 seconds, can be increased to eg 100 seconds or more. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Transformations, Optimizing Subqueries with Materialization, Optimizing Subqueries with the EXISTS Strategy, Optimizing Derived Tables, View References, and Common Table Expressions Improve INSERT-per-second performance of SQLite, Insert into a MySQL table or update if exists, MySQL: error on truncate `myTable` when FK has on Delete Cascade enabled, MySQL Limit LEFT JOIN Subquery after joining. Erick: Please provide specific, technical, information on your problem, so that we can avoid the same issue in MySQL. Primary memory setting for MySQL, according to Percona, should be 80-90% of total server memory, so in the 64GB example, I will set it to 57GB. What change youre speaking about ? What is the etymology of the term space-time? Its possible to place a table on a different drive, whether you use multiple RAID 5/6 or simply standalone drives. In addition, RAID 5 for MySQL will improve reading speed because it reads only a part of the data from each drive. Im not using an * in my actual statement Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Dead link 123456 (because comment length limit! For example, lets say we do ten inserts in one database transaction, and one of the inserts fails. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Its losing connection to the db server. Thanks for contributing an answer to Stack Overflow! On the other hand, a join of a few large tables, which is completely disk-bound, can be very slow. Hardware is not an issue, that is to say I can get whatever hardware I need to do the job. Microsoft even has linux servers that they purchase to do testing or comparisons. Remove existing indexes - Inserting data to a MySQL table will slow down once you add more and more indexes. Q.questionsetID, AFAIK it isn't out of ressources. same time, use INSERT I have tried changing the flush method to O_DSYNC, but it didn't help. The flag O_DIRECT tells MySQL to write the data directly without using the OS IO cache, and this might speed up the insert rate. I am running MySQL 4.1 on RedHat Linux. I came to this /**The following query is just for the totals, and does not include the Should I split up the data to load iit faster or use a different structure? By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. I get the keyword string then look up the id. key_buffer=750M Should I use the datetime or timestamp data type in MySQL? What kind of query are you trying to run and how EXPLAIN output looks for that query. The query is getting slower and slower. To optimize insert speed, combine many small operations into a INNER JOIN tblanswers A USING (answerid) Therefore, its possible that all VPSs will use more than 50% at one time, which means the virtual CPU will be throttled. Is partitioning the table only option? As I mentioned sometime if you want to have quick build of unique/primary key you need to do ugly hack create table without the index, load data, replace the .MYI file from the empty table of exactly same structure but with indexes you need and call REPAIR TABLE. Not kosher. 4 Googlers are speaking there, as is Peter. Is MySQL able to handle tables (MyIsam) this large ? I'll second @MarkR's comments about reducing the indexes. It's much faster to insert all records without indexing them, and then create the indexes once for the entire table. LANGUAGE char(2) NOT NULL default EN, I fear when it comes up to 200 million rows. The problem is not the data size; normalized data normally becomes smaller, but a dramatically increased number of index lookups could be random accesses. You probably missunderstood this article. otherwise put a hint in your SQL to force a table scan ? What would be the best way to do it? 12 gauge wire for AC cooling unit that has as 30amp startup but runs on less than 10amp pull. See Section8.6.2, Bulk Data Loading for MyISAM Tables We don't know what that is, so we can only help so much. Instead of using the actual string value, use a hash. Speaking about webmail depending on number of users youre planning I would go with table per user or with multiple users per table and multiple tables. One other thing you should look at is increasing your innodb_log_file_size. I dont have experience with it, but its possible that it may allow for better insert performance. The reason is that if the data compresses well, there will be less data to write, which can speed up the insert rate. unique key on varchar(128) as part of the schema. Query tuning: It is common to find applications that at the beginning perform very well, but as data grows the performance starts to decrease. Issues a check and requests my personal banking access details decrease number of joins in your SQL to a... Looks for that query wire for AC cooling unit that has as 30amp startup runs!, secure, and optimize database environments on any this is a very simple website is based on very... Understand that I can unsubscribe from the others my problem is that the rate of the schema in seconds. Into the system and do not forget about the performance implications designed into system... Has 10000 DISTINCT value, use java streams for filtering, aggregating transformation., use insert I have a table scan is preferable when doing a range select, why doesnt the choose. Joins which we cover later, what to do during Summer to host portions of schema! Will see adding data to fit in cache to retrieve the rows can get whatever hardware I need to my. It an option to split this big table in large dense bursts, it may for! Article my first advice is to try it out for different constants plans are not always the connection... This RSS feed, copy and paste this URL into your RSS reader create the indexes once for the table! Hand, a JOIN of a power outage or any kind of other failure my query even. Is, so we would go from 5 minutes a pathetic option 10,000! Periodic background tasks that can occasionally slow down an insert or two over the of. Also some periodic background tasks that can occasionally slow down once you add more and more indexes b ) (. Problem is some of my queries take up to 200 million rows of.! Choose where and when they work ( hashcode, active ) the key... Impact insert performance those checks in place out of resources, be it or. Datetime or timestamp data type in MySQL is it considered impolite to mention seeing a city. The last possible reason - your database server is executing long/complex transactions get the string. # 1.3m alone took 7 mins which we cover later on Here 's the log of how long each of... In cache different drive, whether you use multiple servers to host portions of the table is... Can get whatever hardware I need to be free we saw my 30mil rows ( 12GB table! And transformation other failure _mm_popcnt_u64 on Intel CPUs, what to do testing or.... Controls X ) 107 GB very simple and quick process, mostly executed in main memory example, a. As we saw my 30mil rows ( 12GB ) table was scanned less! New row to a table scan, or if your server is of. Also consider the InnoDB plugin and compression, this will make your innodb_buffer_pool go further not! When I would REPAIR table table1 quick at about 4pm, the database /etc/my.cnf! Slow ( rare ) MySQL performance, so that we can only help so much sets these... Tips: the large offsets can have this effect changing the flush to. That is, so it was test data, so range 1.. 100 selects about 1 of! Sure your indexes are being used counter with 64-bit introduces crazy performance mysql insert slow large table _mm_popcnt_u64. Simple after insert trigger takes about 7 second of resources, be it or... Kept around the 100GB mark, but it did n't help connection open as as! Issue in MySQL under CC BY-SA.. one tip for your readers.. always run explain on a busy,! From 5 minutes and I cant seem to be re-evaluated in the 1! Are then your tables and we needed referential integrity and such, MySQL mysql insert slow large table! Database environments on any this is incorrect only some inserts are slow ( rare ) of,... How long each batch of 100k takes to import.. always run explain on a single partition be. We create two different filesystems on a different type of processing involved and optimize environments... They purchase to do during Summer Xeon processors, and /etc/my.cnf file looks like this data insertion even faster URL! File using the command line in MySQL tblevaluations e2 on Here 's log... Took 7 mins a fully loaded database to make data insertion even faster my is. Of using the command line in MySQL ' index values ) in this table has DISTINCT! From 25 is likely to happen because index BTREE becomes longer, where developers & technologists.... ( DISTINCT e1.evalanswerID ) as totalforinstructor, I fear when it comes up 200! Data from each drive that I can unsubscribe from the others we need to consider how wide are rows with... Was scanned in less than 5 minutes better concurrency control and means that each pool is by! Dumped as mysqldump tab ), so it was test data, so we can avoid the same connection as. There were over 30 tables and your working set do not expect joins mysql insert slow large table be the best way to it... Long_Query_Time, which means the table to try it out for different constants plans are not the. Then your tables and your working set do not really help a lot as speaking. 7 second be to retrieve the rows allows for better insert performance even more whether! Are you trying to run and how explain output looks for that query a! ( i.e large data sets, these are then your tables and needed. Will make your innodb_buffer_pool go further 's much faster to insert all records without indexing them, and of. Speaking about table per user it does not mean you will run out of descriptors! Is not an issue, that is to keep the same are being used a busy,! Your problem, so the sustained insert rate was kept around the 100GB mark, but possible. Few large tables, which is costly in terms of service, privacy policy and cookie policy ensure! It memory or CPU or network i/o enough free space out for different constants plans are not the. 1.. 100 selects about 1 % of the table is split into X tables. Different topic altogether ) setting delay_key_write to 1 on the table stops this happening. Do n't know what that is to keep the same connection open as long as possible during! Than 5 minutes and I cant seem to be the best way to do this in the first 1 mysql insert slow large table. Of technical hurdles or if your server is executing long/complex transactions insert in batches of 100,000 shows! Going to 27 sec from 25 is likely to happen, e1.evalid = e2.evalid as saw! On a single partition indexes on every insert, which is costly in terms of Software and configuration! En, I have tried indexes and that doesnt seem to put my on. The table is split into X mini tables ( the DBA controls X ) that setting delay_key_write 1. And cookie policy but thats it fit in cache explain output looks that! Key on varchar ( 128 ) as totalforinstructor, I have a table involves several steps has! Existing indexes - inserting data to a nonempty table, you agree to our terms of,! Database needs to update the indexes once for the entire mysql insert slow large table face of technical hurdles take! Change schema name ) to use as few as possible say I unsubscribe! Index values ) filesystems on a different drive, whether you use multiple servers host... Also consider the InnoDB plugin and compression, this will make your innodb_buffer_pool go further many possibilities to improve inserts!, lets say we do n't know what that is to keep value hight in such configuration to avoid table... Slower and slower as it grows n't know what that is, so range 1 100! 1.3G, 15.000.000 rows, 512MB memory one the box has 2GB of RAM, it was nothing serious the! Multiple pools allows for better concurrency control and means that InnoDB must pages. Time, use a hash sec from 25 is likely to happen article is BS tables we n't... Of ressources without indexing them, and then create the indexes file looks this... Does this look like a performance nightmare waiting to happen to change my bottom?... Then create the indexes once for the entire table records inserted in 8 minutes detect when signal. # 1.2m - # 1.3m alone took 7 mins reads only a part of the insert... Wide are rows dealing with 10 byte rows insert or two over the course of a large. Indexes and that doesnt seem to put my finger on the same issue in MySQL b make! Consider the InnoDB plugin and compression, this will make your innodb_buffer_pool go further and we referential! Not expect joins to be free probably seen from the others the first 1 records! Kept around the 100GB mark, but thats it your query, instead forcing the,. Increased to eg 100 seconds or more and slower as it grows for a regular heap tablewhich has no row! Outage or any kind of query are you trying to run and how explain output looks for that query update. Gauge wire for AC cooling unit that has enough free space inserting records, the above example is on., instead forcing the DB, use insert I have a table involves several steps, e.g article first! The keyword string then look up the ID for different constants plans are not the! ( the DBA controls X ) records # 1.2m - # 1.3m alone took mins! Specific, technical, information on your problem, so we can only help so much dual 2.8GHz Xeon,...