A Database already has up to 25-30 tables and all are MyISAM. Most of these tables are related to each other meaning a lot of queries use joins on IDs and retrieve data.
One of the tables contain 7-10 Million records and it becomes slow if i want to perform a search or update or even retrieval of all data. Now i proposed a solution to my boss saying that converting tables into InnoDB might give better performance.
I also explained the benefits of InnoDB:
Since we anyways join multiple tables on keys and they are related, it will be better to use foreign keys and have relational database which will avoid Orphan Rows. I found around 10-15k orphan rows in one of the big tables and had to manually remove them.
Support for transactions, we perform big updates from time to time and if one of them fails on the way we have to replace the entire table with the backed-up one and run the update again to make sure that all queries were executed. With InnoDB we can revert back any changes from query 1 if query 2 fails.
Now the response i got from my boss is that I need to prove that InnoDB will run faster than MyISAM. My question is, wont above 2 things improve the speed of the application itself by eliminating orphan rows?
In general is MyISAM faster than InnoDB?
Note: using MySQL 5.5
You should also mention to your boss probably the biggest benefit you get from InnoDB for large tables with both read/write load - You get row-level locking rather than table-level locking. This can be a great performance benefit for the application in cases where you see a lot of waits for table locks to be released.
Of course the best way to convince your boss is to prove it. Make copies of your large table and place on a testing database. Make one version of data in MyISAM and one in InnoDB. Then run load testing against it with a load mix that approximates your current DB read/write activity. Find out for yourself if it is better.
Just updated for your comment that you are on 5.5. With 5.5 it is a no brainer to use InnoDB. MyISAM engine basically has seen no improvement over the last several years and development effort has been around InnoDB. InnoDB is THE MySQL engine of choice going forward.
Related
I have a database with 48 tables and 45 of the tables are InnoDB.
I have 3 MyISAM tables which range in size from 200 records to 1.5Mil and also a 6.5Mil entries.
These 3 tables contain GEO Location information and are read only (never write - unless i was to update one - extremely infrequently).
I considered changing them to InnoDB to make the database 100% the same but then read the MYiSAM is faster. Note: I don't need any of the special INNODB functions - its just selects/joins... thats it.
Should I keep these MyISAM or change them to InnoDB?
thx
MyISAM used to be faster years ago, but if you use any reasonably current version of InnoDB, then InnoDB is faster for most workloads. Here's a performance comparison from way back in 2007 that shows InnoDB already matched or bettered MyISAM in all but a few types of queries.
http://www.mysqlperformanceblog.com/2007/01/08/innodb-vs-myisam-vs-falcon-benchmarks-part-1/
Since that test in 2007, InnoDB has continued to get better, whereas the MySQL developers have spent virtually no time improving MyISAM. It's dead, Jim.
The only cases where MyISAM may be faster is when doing full table-scans, and you should try to define indexes to avoid table-scans anyway.
InnoDB has been the default storage engine in MySQL since 5.5 (circa 2010). With each major version of MySQL, it becomes more clear that MyISAM is going away.
InnoDB has many benefits even if you don't use the explicit features like transactions or foreign keys. Try this:
Execute a long-running UPDATE against a MyISAM table.
Interrupt it partway through. How many rows have been changed? Some, but not all.
Repeat the same test with an InnoDB table. How many rows have been changed? Zero!
InnoDB supports atomic changes, so every SQL statement either succeeds completely, or else rolls back. You won't get partially-completed changes.
InnoDB also support crash recovery, so you won't lose data if mysqld ever crashes. MyISAM is renowned for corrupting tables during a crash.
InnoDB also caches data in RAM (the InnoDB buffer pool), whereas MyISAM relies on the filesystem cache to speed up data I/O. This makes some queries a lot faster in InnoDB if you have enough RAM.
Use MyISAM only if you don't care about your data.
No need to change In INNODB. As you say thay have lot of records SO thay are faster as MYISAM
MyISAM in most cases will be faster than InnoDB for run of the mill sort of work. Selecting, updating and inserting are all very speedy under normal circumstances.
I wouldn't bother changing it. I was just researching the same thing and came across this useful post: http://www.kavoir.com/2009/09/mysql-engines-innodb-vs-myisam-a-comparison-of-pros-and-cons.html
The main reason you'd want Innodb would be for data integrity and to avoid locking the entire table on inserts. But if you're not doing a lot of inserts and these are not high traffic tables, then why make the change?
No change is necessary, i am working on similar project where the database is going to be used for read-only and Myisam is the best option for it.
In addition you can even use sphinx if you want faster reads.
hope this helps.
We have an update process which currently takes over an hour and means that our DB is unusable during this period.
If I setup up replication would this solve the problem or would the replicated DB suffer from exactly the same problem that the tables would be locked during the update?
Is it possible to have the replicated DB prioritize reading over updating?
Thanks,
D
I suspect that with replication you're just going to be dupolicating the issue (unless most of the time is spent in CPU and only results in a couple of records being updated).
Without knowing a lot more about the scema, distribution and size of data and the update process its impossible to say how best to resolve the problem - but you might get some mileage out of using innodb instead of C-ISAM and making sure that the update is implemented as a number of discrete steps (e.g. using stored procuedures) rather than a single DML statement.
MySQL gives you the ability to run queries delaye. Example: "INSERT DELAYED INTO...", this will cause the query to only be executed when MYSQL has time to take the query.
Based on your input, it sounds like you are using MyISAM tables, MyISAM only support table-wide locking. That means that a single update will lock the whole database table until the query is completed. InnoDB on the other hand uses row locking, which will not cause SELECT queries to wait(hang) for updates to complete.
So you have the best chances of a better sysadmin life if you change to InnoDB :)
When it comes to replication it is pretty normal to seperate updates and selects to two different MySQL servers, and that does tend to work very well. But if you are using MyISAM tables and does a lot of updates, the locking issue itself will still be there.
So my 2 cents: First get rid of MyISAM, then consider replication or a better scaled MySQL server if the problem still exists. (The key for good performance in MySQL is to have at least the size of all indexes across all databases as physical RAM)
I've read various threads about which is better between InnoDB and MyISAM. It seems that the debates are to use or the other. Is it not possible to use both, depending on the table?
What would be the disadvantages in doing this? As far as I can tell, the engine can be set during the CREATE TABLE command. Therefore, certain tables which are often read can be set to MyISAM, but tables that need transaction support can use InnoDB.
You can have both MyISAM and InnoDB tables in the same database. What you'll find though, when having very large tables is, MyISAM would cause table-lock issues. What this ultimately does is, it locks the whole table for a single transaction, which is very bad if you have many users using your website. e.g If you have a user searching for something on your site and the query takes minutes to complete, no other users could use your site during that period because the whole table is locked.
InnoDB on the other hand uses row-level locking, meaning, that row is the only row locked from the table during a transaction. InnoDB can be slower at searches because it doesn't offer full text search like MyISAM, but that isn't a big problem when you compare it to table-level locking of MyISAM. If you use InnoDB, like many large sites, then you could use a server side search engine like Sphinx for full text searches. Or you could even use a MyISAM table to do the searching like f00 suggested. I'd personally recommended InnoDB mainly because of the row-level locking feature, but also because you can implement full text searching in many other ways.
Basically, if you have a message board application with lots of selects, inserts as well as updates, InnoDB is probably the generally appropriate choice.
But if you're not building something like that (or any other thing with registered users) and your working mostly with static content (or more reads than writes), then you could use MyISAM.
Yes indeed you may use both in the same database, you may choose for each table separately.
In short, InnoDB is good if you are working on something that needs a reliable database that can handles a lot of INSERT and UPDATE instructions.
and, MyISAM is good if you needs a database that will mostly be taking a lot of read (SELECT) instructions rather than write (INSERT and UPDATES), considering its drawback on the table-lock thing.
you may want to check out;
Pros and Cons of InnoDB
Pros and Cons of MyISAM
You don't choose InnoDB or MyISAM on a database level, but instead on a table level. So within the one database you could have some tables running the InnoDB engine and some running MyISAM. As you pointed out, you could choose to use InnoDB on the tables that require transactions etc, and MyISAM where you need other features such as fulltext searching.
I have a huge file (~26 MB) with around 200 columns & 30000 records. I want to import it into a database (InnoDB Engine). I wont't be updating or deleting records ever. ALthough I will be querying a lot of records from the table with high complexity in where clause. Which table engine should i prefer for faster query response? Will it really make a lot of difference?
PS: All my other tables use InnoDB.
Also How can I avoid manually creating a table with 200 columns and specifying the datatype for each of them. Most of the columns are float and few are varchar and date.
Usually the answer to "which is faster, ISAM or innodb" would be ISAM
But for best performance with a table which has very few updates you might want to have a look at Infobright's columnar db (which is integrated into mysql).
However with only 30k rows you'll not see a significant difference between innodb, isam and infobright.
OTOH, you really should have a long hard look at whether you really need 200 columns in a single table. I suspect that's not the case - and the schema is far more important in determining performance than the storage engine.
when dealing with large amounts of data innodb fares better then myisam.,
http://www.mysqlperformanceblog.com/2007/01/08/innodb-vs-myisam-vs-falcon-benchmarks-part-1/
and
http://www.cftopper.com/index.cfm?blogpostid=84
James Day, a MySQL Support Engineer and Wikipedia engineer recommends that people use InnoDB all the time unless for some reason if becomes apparent that you need MyISAM:
"I'd go with InnoDB until it's been proved that it's unsuitable. The first reason is reliability. Get a crash with MyISAM and you have the unreliable and slow, related to table size, table repair process. Same thing with InnoDB and you instead get the fixed time, fast and reliable log apply/rollback process. As the data set gets bigger, this matters more and more, as it does if you want to do things like sleep instead of being woken up in the middle of the night to fix a crashed table.
For reliability and performance, we use InnoDB for almost everything at Wikipedia - we just can't afford the downtime implied by MyISAM use and check table for 400GB of data when we get a crash."
My MysQL database contains multiple MyISAM tables, with each table containing millions of rows. There is a heavy insert load on the database, so I cannot issue SELECTs on that live database. Instead, I create a replica of the database for queries and conduct analysis on that.
For the analysis, I need to issue multiple parallel queries. The queries are independent (i.e., the results of the queries are not combined together), but they operate on same tables most of the time. As far as I know, the entire MyISAM table is locked for each query, which means parallel independent queries would be slow. Ideally, I would prefer an engine that supports "NO LOCKING". I am assuming MySQL doesnt have such an engine, so should I use InnoDB? I might be missing lot of things here. Please suggest what is the right path to take here.
Thanks
MyISAM read locks are compatible, so the SELECT queries won't lock each other.
If your analysis queries on the replica database don't write, only read, then it's OK to use MyISAM.
You could stick to MyISAM and use INSERT DELAYED:
When a client uses INSERT DELAYED, it gets an okay from the server at once, and the row is queued to be inserted when the table is not in use by any other thread.
Another major benefit of using INSERT DELAYED is that inserts from many clients are bundled together and written in one block. This is much faster than performing many separate inserts.