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.
Related
I read that Innodb is better to use on a table that get a lot's of insert records simultaneously. My application gets about 50 records per seconds. So for these tables should I use Innodb, right?
In the other hand i have some tables that are only used for select, they get few updated or have few new insert. Is MyIsam faster for select ?
If it's the case, is it better to leave some table with MyIsam and some with Innodb or should i use all tables with the same engine ?
My application also searches a lot on the tables that i want to pass in Innodb. What should i do ?
you can check these:
Reasons to use MyISAM:
Tables are really fast for select-heavy loads
Table level locks limit their scalability for write intensive multi-user environments.
Smallest disk space consumption
Fulltext index
Merged and compressed tables.
Reasons to use InnoDB:
ACID transactions
Row level locking
Consistent reads – allows you to reach excellent read write concurrency.
Primary key clustering – gives excellent performance in some cases.
Foreign key support.
Both index and data pages can be cached.
Automatic crash recovery – in case MySQL shutdown was unclean InnoDB tables will still
recover to the consistent state- No check repair like MyISAM may require. All updates have to pass through transactional engine in
InnoDB, which often decreases - performance compared to
non-transactional storage engines.
quoted from here
and for the last part:
REMEMBER! It's OK to mix table types in the same database! In fact it's recommended and frequently required. However, it is important to note that if you are having performance issues when joining the two types, try converting one to the other and see if that fixes it. This issue does not happen often but it has been reported.
quoted from here
I hope that's enough :D
Yes you can, but I'd go with InnoDB only unless there is some serious performance bottleneck
same question on SO
MySQL forum
In short yes you can mix and match to your hearts content.
Keep the following in mind:
InnoDB is ACID complaint. Thus is you need any ACID features use InnoDB. MyISAM is does not support a lot of things like foreign key constraints for example.
Now speed is hard to quantify exactly. Depending on execution paths you might get very big or very small speed differences.
Test and check there is no right or wrong answer here.
I'm currently have a few tables with InnoDB Engine. 10-20 connections are constantly inserts data into those tables. I use MySQL RDS instance on AWS. Metric shows about 300 Write IOPS (counts/second). However, INSERT operations lock the table, and if someone want to perform a query like SELECT COUNT(*) FROM table; it could literally take a few hours for the first time before MySQL cache the result.
I'm not a DBA and my knowledge about DB are very limited. So the question is if I'll switch to MyISAM Engine will it help to improve the time of READ operations?
SELECT COUNT(*) without WHERE is bad query for InnoDB, as it does not cache the row count like MyISAM do. So if you have issue with this particular query, you have to cache the count somewhere - in a stats table for example.
After you remove this specific type of query, you can talk about InnoDB vs MyISAM read performance. Generally writes do not block reads in InnoDB - is uses MVCC for this. InnoDB performance however is very dependent of how much RAM you have set for the buffer pool.
InnoDB and MyISAM are very different in how they store data. You can always optimize for one of them and knowing the differences can help you in designing your application. Generally you can have as good performance for reading as in MyISAM in InnoDB tables - you just can use count without where clause, and you always should have a suitable index for where clauses, as in InnoDB table scan will be slower than in MyISAM.
I think you should stick with your current setup. InnoDB is supposed not to lock the table when inserting rows, since it uses the MVCC technique. On the other hand, MyISAM locks the entire table when new rows are inserted.
So, if you have many writes, you should stick with InnoDB.
Innodb is a better overall engine in general. There are some benchmarks out there that put read operations in myiasm a little ahead of innodb. However, if your site is big enough to notice this performance difference, you should be on innodb anyway because of all the other efficiencies. Innodb alone wins because of the row level locking instead if table level locking in myiasm when backing up your database.
I have a table with 17 million rows. I need to grab 1 column of that table and insert it all into another table. Here's what I did:
INSERT IGNORE INTO table1(name) SELECT name FROM main WHERE ID < 500001
InnoDB executes in around 3 minutes and 45 seconds
However, MyISAM executes in just below 4 seconds. Why the difference?
I see everyone praising InnoDB but honestly I don't see how it's better for me. It's so much slower. I understand that it's great for integrity and whatnot, but many of my tables will not be updated (just read). Should I even bother with InnoDB?
The difference is most likely due to configuration of innoDB, which takes a bit more tweaking than myISAM. The idea of innoDB is to keep most of your data in memory, and flushing/reading to disk only when you have a few spare cpu cycles.
should you even bother with InnoDB is a really good question. If you're going to keep using MySQL, it's highly recommended you get some experience with InnoDB. But if you're doing a quick-and-dirty job for a database that won't see a lot of traffic and not worried about scale, then the ease of MyISAM may just be a win for you. InnoDB can be overkill in many instances where someone just wants a simple database.
but many of my tables will not be updated
You can still get a performance lift from InnoDB if you are doing 99% reading. If you configure your buffer pool size to hold your entire database in memory, InnoDB will NEVER have to go to disk to get your data, even if it misses the mysql query cache.
In MyISAM, there is a good chance you have to read the row from disk, and you're leaving the operating system to do the caching and optimization for you.
innodb-buffer-pool-size
My first guess is to check innodb_buffer_pool_size which ships out of the box set to 8M. It's recommended to have this around 80% of your total memory. Once you hit that limit, innodb performance will drop significantly because it needs to flush something out of the buffer to make room for the new data, which can be expensive
autocommit=0
Also, make sure autocommit is turned off while you load your table, or flushing will happen on every insert. You can turn it back on after you're done, and it's a client-side setting. very safe.
Loading tables typically happens once
Think about if you really want to tune your database to accommodate "inserting 17million rows". How often do you do this? MyISAM might be quicker in this instance, but when you have 100 concurrent connections all reading and modifying this table at the same time, you'll find a well-tuned innoDB will win and MyISAM will choke on table locks.
How MyISAM sees this operation
MyISAM will be very good at this without any tuning, because under the covers, you're simply appending each row to a file (and updating an index). Your OS and disk caching will handle all those performance problems.
How InnoDB sees this operation
Innodb will know the table needs a write, so it throws the row into the insert buffer.
You give it no time before the next insert, so innoDB has no time to deal with the buffer, it runs out of room and is forced to 'hold up' the insert while it writes to the buffer pool and updates indexes.
Next, your buffer pool fills up, and innoDB is forced to 'hold up' the insert and flush some page out of the buffer pool to disk.
And you keep throwing inserts at it like crazy.
Note that when you do tune InnoDB to give you a MySQL> prompt very fast after you do this, InnoDB will still be scrambling underneath the covers to catch up in it's spare time, but will be willing to execute a new transaction for you.
MUST READ:
http://www.mysqlperformanceblog.com/2007/11/01/innodb-performance-optimization-basics/
http://dev.mysql.com/doc/refman/5.0/en/innodb-tuning.html (see bulk data loading tips)
You're saying right upto some extend. InnoDB is slower than MyISAM but in which cases?
Everything is not made to meet everyone's requirements. INNODB is a transactional database engine while MyISAM is not. Therefore to make it ACID compliance and transactions aware storage engine, we have to pay its cost in terms of response time.
Further more InnoDB runs faster if it is properly tuned using my.ini or other configuration file.
At the end I am able to understand following reasons why people are praising InnoDB:
It is ACID compliant and transaction supported engine
It take row-level locking while working on a table while MyISAM take table-level locks
InnoDB is highly tunable for multi-core/multi-process machines to improve concurrency
Last but not the least comment from my side; anything can meet "everyone's" needs so its solely depends in which scenario you're comparing both engines.
Check out MYISAM vs Innodb comparison on Wikipedia.
http://en.wikipedia.org/wiki/Comparison_of_MySQL_database_engines
Sometimes I got asked on some interviews: what benefits does InnoDB have against MyISAM and when MyISAM is better than InnoDB? It's all clear about the first part of question: InnoDB is transaction compliant, row-level blocking instead of table-level blocking, foreign key support and some others, these points just came to mind immidiately.
But when MyISAM is really better than InnoDB?
MyISAM is better than InnoDB when you don't need those advanced features and storage speed is more important than other concerns. MyISAM also allows full-text searches to be performed inside the database engine itself, instead of needing to query results and then search them as an array or whatever in your application.
InnoDB is a reasonable choice if you need to store data with a high degree of fidelity with complicated interactions and relationships. MyISAM is a reasonable choice if you need to save or load a large number of records in a small amount of time.
I wouldn't recommend using MyISAM for data that matters. It's great for logging or comments fields or anything where you don't particularly care if a record vanishes into the twisting nether. InnoDB is good for when you care about your data, don't need fast searches and have to use MySQL.
It's also worth mentioning that InnoDB supports row-level locking, while MyISAM only supports table-level locking - which is to say that for many common situations, InnoDB can be dramatically faster due to more queries executing in parallel.
The bottom line: Use InnoDB unless you absolutely have to use MyISAM. Alternatively, develop against PostgreSQL and get the best of both.
MyISAM doesn't support transactions (and the other things mentioned) so it can work faster. MyISAM is a way to achieve higher performance in those situations when you do not need these features.
MyISAM supports full text, as mentioned, but also supports the MERGE table type. This is handy when you have a large table and would like to "swap" out/archive parts of it periodically. Think about a logging or report data that you want to keep the last quarter and/or year. MyISAM handles large amounts of data like this better, when you are mainly inserting and rarely updating or deleting.
InnoDB performance drops pretty quickly and dramatically once you can't fit the indexes in memory. If your primary key is not going to be a number (i.e. auto increment), then you may want to rethink using InnoDB. The primary key is replicated for every index on an InnoDB table. So if you have a large primary key and a few other indexes, your InnoDB table will get very large very quick.
There are a few features that MySQL only has implemented for MyISAM (such as native fulltext indexing).
That said, InnoDB is still typically better for most production apps.
Also: Full-text search in mySQL is only supported in myISAM tables.
MyISAM has a very simple structure, when compared with InnoDB. There is no row versioning, there's one file per table and rows are stored sequentially. However, while it supports concurrent inserts (SELECTs and 1 INSERT can run together), it also has table-level locks (if there are 2 INSERTs on the same table, 1 has to wait). Also, UPDATEs and DELETEs are slow because of the structure of the data files.
MyISAM doesn't support transactions or foreign keys.
Generally, MyISAM should be better if you work on general trends (so you don't care about the correctness of individual rows) and data is updated by night or never. Also, it allows to move individual tables from one server to another, via the filesystem.
InnoDB supports very well concurrency and transactions. Has a decent support for fulltext and an almost-decent support for foreign keys.
I have 2 tables in which I want more robustness and fortunately don't require frequent rapid fulls of data and examination.
All other tables would inevitably be MyISAM.
Can I safely use both (I've read a handful of discouragements from this) without fearing bugs or data getting affected by differences between engines?
You CAN but this introduces a number of disadvantages:
Your server tuning will now necessarily be a compromise - you cannot use all the memory for either MyISAM OR InnoDB (NB: This does not apply if they are on different servers)
Replication fails in a number of edge-cases, because if you have a failed transaction which contained changes to some MyISAM tables, it can neither correctly commit it nor roll it back
You still can't back up your server using MVCC, because you'd still not get a consistent snapshot of MyISAM tables
So basically, I'd encourage you to switch wholly to InnoDB. Then you can pretty much forget about MyISAM and not devote resources to it, and get the full benefits of using InnoDB. Anyone who thinks MyISAM is faster is either not tuning InnoDB correctly, or has such small data that who cares.
MyISAM does faster table scans, but if you're doing those on large tables, you have bigger problems.
Yes, you can.
Note that only InnoDB tables support transactions and FOREIGN KEY relationships.