REPLACE INTO is asinine because it deletes the record first, then inserts the new one. VPS is an isolated virtual environment that is allocated on a dedicated server running a particular software like Citrix or VMWare. Some people would also remember if indexes are helpful or not depends on index selectivity how large the proportion of rows match to a particular index value or range. The fact that Im not going to use it doesnt mean you shouldnt. Regarding your TABLE, there's 3 considerations that affects your performance for each record you add : (1) Your Indexes (2) Your Trigger (3) Your Foreign Keys. I have made an online dictionary using a MySQL query I found online. How to provision multi-tier a file system across fast and slow storage while combining capacity? A.answername, 9999, Why don't objects get brighter when I reflect their light back at them? The load took some 3 hours before I aborted it finding out it was just This reduces the I'd expected to add them directly, but doing some searching and some recommend creating a placeholder table, creating index (es) on it, dumping from first table and then loading to second table. Id suggest you to find which query in particular got slow and post it on forums. single large operation. Just to clarify why I didnt mention it, MySQL has more flags for memory settings, but they arent related to insert speed. statements. This is considerably faster (many times faster in some cases) than using separate single-row INSERT statements. Have fun with that when you have foreign keys. Even if a table scan looks faster than index access on a cold-cache benchmark, it doesnt mean that its a good idea to use table scans. COUNTRY char(2) NOT NULL, ASets.answersetname, http://dev.mysql.com/doc/refman/5.0/en/innodb-configuration.html How are small integers and of certain approximate numbers generated in computations managed in memory? e3.answerID = A.answerID, GROUP BY A query that gets data for only one of the million users and needs 17 seconds is doing something wrong: reading from the (rated_user_id, rater_user_id) index and then reading from the table the (hundreds to thousands) values for the rating column, as rating is not in any index. The table contains 36 million rows (Data size 5GB, Index size 4GB). I then use the id of the keyword to lookup the id of my record. Transformations, Optimizing Subqueries with Materialization, Optimizing Subqueries with the EXISTS Strategy, Optimizing Derived Tables, View References, and Common Table Expressions This means that InnoDB must read pages in during inserts (depending on the distribution of your new rows' index values). is there some sort of rule of thumb here.. use a index when you expect your queries to only return X% of data back? When I needed a better performance I used a C++ application and used MySQL C++ connector. 2. set global slow_query_log=on; 3. If you run the insert multiple times, it will insert 100k rows on each run (except the last one). When you're inserting records, the database needs to update the indexes on every insert, which is costly in terms of performance. They can affect insert performance if the database is used for reading other data while writing. Let's begin by looking at how the data lives on disk. innodb_flush_log_at_trx_commit=0 innodb_support_xa=0 innodb_buffer_pool_size=536870912. proportions: Inserting indexes: (1 number of indexes). I am trying to use Mysql Clustering, to the ndbcluster engine. This article is about typical mistakes people are doing to get their MySQL running slow with large tables. 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. Some of the memory tweaks I used (and am still using on other scenarios): The size in bytes of the buffer pool, the memory area where InnoDB caches table, index data and query cache (results of select queries). Nice thanks. character-set-server=utf8 Sorry for mentioning this on a mysql performance blog. it could be just lack of optimization, if youre having large (does not fit in memory) PRIMARY or UNIQUE indexes. The first 1 million row takes 10 seconds to insert, after 30 million rows, it takes 90 seconds to insert 1 million rows more. my actual statement looks more like query. The reason for that is that MySQL comes pre-configured to support web servers on VPS or modest servers. Use SHOW PROCESSLIST to see what is running when a slow INSERT occurs. Why? Now I have about 75,000,000 rows (7GB of data) and I am getting about 30-40 rows per second. How small stars help with planet formation. What screws can be used with Aluminum windows? It uses a maximum of 4 bytes, but can be as low as 1 byte. Needless to say, the cost is double the usual cost of VPS. The problem is unique keys are always rebuilt using key_cache, which There are 277259 rows and only some inserts are slow (rare). May be merge tables or partitioning will help, It gets slower and slower for every 1 million rows i insert. Now if we take the same hard drive for a fully IO-bound workload, it will be able to provide just 100 row lookups by index per second. 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. The default value is 134217728 bytes (128MB) according to the reference manual. This article is not about MySQL being slow at large tables. Also, I dont understand your aversion to PHP what about using PHP is laughable? e3.evalid = e4.evalid max_connect_errors=10 If an insert statement that inserts 1 million rows is considered a slow query and recorded in the slow query log, writing this log will take up a lot of time and disk storage space. In what context did Garak (ST:DS9) speak of a lie between two truths? It's much faster. You should experiment with the best number of rows per command: I limited it at 400 rows per insert, but I didnt see any improvement beyond that point. 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. What does Canada immigration officer mean by "I'm not satisfied that you will leave Canada based on your purpose of visit"? ASets.answersetid, 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. variable to make data insertion even faster. 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 .. Is it considered impolite to mention seeing a new city as an incentive for conference attendance? A.answerID, InnoDB doesnt cut it for me if the backup and all of that is so very cumbersome (mysqlhotcopy is not available, for instance) and eking performance out of an InnoDB table for raw SELECT speed will take a committee of ten PhDs in RDBMS management. Dont recommend REPLACE INTO, its asinine. How can I detect when a signal becomes noisy? I overpaid the IRS. I am running MySQL 4.1 on RedHat Linux. Just my experience. As my experience InnoDB performance is lower than MyISAM. Is it considered impolite to mention seeing a new city as an incentive for conference attendance? If youre following my blog posts, you read that I had to develop my own database because MySQL insert speed was deteriorating over the 50GB mark. Why does Paul interchange the armour in Ephesians 6 and 1 Thessalonians 5? - Rick James Mar 19, 2015 at 22:53 What gives? Since I used PHP to insert data into MySQL, I ran my application a number of times, as PHP support for multi-threading is not optimal. Learn more about Percona Server for MySQL. I do multifield select on indexed fields, and if row is found, I update the data, if not I insert new row). what changes are in 5.1 which change how the optimzer parses queries.. does running optimize table regularly help in these situtations? INNER JOIN tblanswersetsanswers_x ASAX USING (answersetid) With this option, MySQL will write the transaction to the log file and will flush to the disk at a specific interval (once per second). I am surprised you managed to get it up to 100GB. @ShashikantKore do you still remember what you did for the indexing? This does not take into consideration the initial overhead to connect_timeout=5 Hardware is not an issue, that is to say I can get whatever hardware I need to do the job. Number of IDs would be between 15,000 ~ 30,000 depends of which data set. Some collation uses utf8mb4, in which every character is 4 bytes. I am building a statistics app that will house 9-12 billion rows. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. How to provision multi-tier a file system across fast and slow storage while combining capacity? Here is a little illustration Ive created of the table with over 30 millions of rows. How can I make the following table quickly? Here's the log of how long each batch of 100k takes to import. What PHILOSOPHERS understand for intelligence? And the last possible reason - your database server is out of resources, be it memory or CPU or network i/o. LOAD DATA INFILE is a highly optimized, MySQL-specific statement that directly inserts data into a table from a CSV / TSV file. (In terms of Software and hardware configuration). @Kalkin: That sounds like an excuse to me - "business requirements demand it." AND e2.InstructorID = 1021338, ) ON e1.questionid = Q.questionID Q.question, LEFT JOIN (tblevalanswerresults e1 INNER JOIN tblevaluations e2 ON 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. The database was throwing random errors. Totals, How to add double quotes around string and number pattern? 4. show variables like 'long_query_time'; 5. COUNT(DISTINCT e1.evalanswerID) AS totalforinstructor, The second set of parenthesis could have 20k+ conditions. And how to capitalize on that? At this point it is working well with over 700 concurrent user. SELECT 2. Also do not forget to try it out for different constants plans are not always the same. Lets say we have a table of Hosts. interactive_timeout=25 Im doing the following to optimize the inserts: 1) LOAD DATA CONCURRENT LOCAL INFILE '/TempDBFile.db' IGNORE INTO TABLE TableName FIELDS TERMINATED BY '\r'; 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. The reason is that if the data compresses well, there will be less data to write, which can speed up the insert rate. What sort of contractor retrofits kitchen exhaust ducts in the US? Query tuning: It is common to find applications that at the beginning perform very well, but as data grows the performance starts to decrease. Here's the EXPLAIN output. I would try to remove the offset and use only LIMIT 10000: Thanks for contributing an answer to Database Administrators Stack Exchange! For RDS MySQL, you can consider using alternatives such as the following: AWS Database Migration Service (AWS DMS) - You can migrate data to Amazon Simple Storage Service (Amazon S3) using AWS DMS from RDS for MySQL database instance. We have applications with many billions of rows and Terabytes of data in MySQL. Using precalculated primary key for string, Using partitions to improve MySQL insert slow rate, MySQL insert multiple rows (Extended inserts), Weird case of MySQL index that doesnt function correctly, mysqladmin Comes with the default MySQL installation, Mytop Command line tool for monitoring MySQL. Reference: MySQL.com: 8.2.4.1 Optimizing INSERT Statements. It might be a bit too much as there are few completely uncached workloads, but 100+ times difference is quite frequent. That will house 9-12 billion rows visit '' 100k rows on each run ( the! Thessalonians 5 your Answer, you agree to our terms of software and hardware configuration.... 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