Is there a real performance difference between int and VARCHAR?
My conclusion is that there’s no performance difference for this particular use case. Depends on the length.. If the varchar will be 20 characters, and the int is 4, then if you use an int, your index will have FIVE times as many nodes per page of index space on disk…
Which is better A varchar or a length in MySQL?
MySQL – varchar length and performance. So the general piece of advice is to use the smallest type possible, because it can potentially create performance or management problems otherwise. A VARCHAR(100) is better than VARCHAR(255) (although a VARCHAR(20) would be better), even if you do not know the exact length.
Which is faster, an int or an index?
Index or not, int is a lot faster (the longer the varchar, the slower it gets). Another reason: index on varchar field will be much larger than on int. For larger tables it may mean hundreds of megabytes (and thousands of pages). That makes the performance much worse as reading the index alone requires many disk reads.
How big is a varchar field in InnoDB?
So, it is very likely that you won’t be able to index fully a VARCHAR (255) field (assuming you use utf8 or any other variable length-encoding). Additionally, the maximum inline row size for InnoDB is half a page (around 8000 bytes), and variable-lenght fields like BLOB or varchar, can be stored off-page if they do not fit on the half-page.
Which is faster to create index for int or bigint?
Especially, when the primary key is by definition an index which means, to create an index for bigint would be slower than create an index for int, with the same amount of data, right ?
How big is a bigint table compared to an int table?
The average row size of both tables are virtually the same. This is because the integer column occupies 8 bytes (4 bytes for a value and 4 bytes of alignment) exactly like bigint (8 bytes for a value without a filler). The same applies to index entries.