So I am a beginner and have just learned MySQL by myself for a few months. I always use phpMyAdmin in my work. My past work only involved tables with about 100k rows so there is no major issue.
However my client now wants to store about 8 million rows in a table. Is it too much for MySQL/phpMyAdmin to store and handle?
Thanks very much.
Just Google it:
In InnoDB, with a limit on table size of 64 terabytes and a MySQL row-size limit of 65,535 there can be 1,073,741,824 rows. That would be minimum number of records utilizing maximum row-size limit. However, more records can be added if the row size is smaller
This is what it says.
So as the answer there can be 1,073,741,824 rows.
We don't know how big or small of your record. Short records can few integer fields or our records might be really big with hundreds of text or varchar fields. So measure of file size is the best way . This Officilal Information may help you
Related
I have a huge table in MySQL and am looking to make it smaller by optimizing the data.
Now I was wondering if MySQL has features that allow me to calculate how many bytes I would save by deleting certain rows or columns?
So something like: select bytes_used(*) from (subquery...), or something like this?
I can of course duplicate the table and compare the storage used after deleting the rows or columns, but that takes up a lot of time. Some data I can migrate or delete and build differently in the app without breaking anything.
This question is about assessing the possible gains and if this course of action is worth pursuing.
Any other help regarding calculation of disk space with MySQL data is also very welcome. I know that you can see how much data a table takes up in phpMyAdmin, but I'm looking further than this.
Addendum: I'm looking for data size on the row or column level, not whole tables.
Getting data size based on rows or columns is not possible, but you can get the data for entire tables like this:
You can query information_schema.TABLES table to get the disk space used by table, e.g.:
SELECT *
FROM information_schema.TABLES
WHERE TABLE_NAME = `<your_table>`;
This has the following columns (as per the documentation here):
DATA_LENGTH : For MyISAM, DATA_LENGTH is the length of the data file,
in bytes. For InnoDB, DATA_LENGTH is the approximate amount of memory
allocated for the clustered index, in bytes. Specifically, it is the
clustered index size, in pages, multiplied by the InnoDB page size.
AVG_ROW_LENGTH: The average row length.
These will give you an idea of how much space is used by the table and how much space you will approximately gain if you delete some rows.
What are problems occur when mysql server table contains more than 120 columns ?
from a technical point of view without any consideration on the reasons for which you need 120 columns in a table mysql documentation 5.7 says:
Column Count Limits
MySQL has hard limit of 4096 columns per table, but the effective
maximum may be less for a given table.
https://dev.mysql.com/doc/refman/5.7/en/column-count-limit.html
This is bad practice to have 120 columns in a table better to split into multiple tables.
Since MYSQL is famous for relation database, So make relation based tables structure.
List of issues comes once your application become bigger.
Application gets slow (Since data fetching from table is slowly).
If your internet is slow, then you may not load the application page.
If huge amount of data is loaded at once due to the numbers of columns, then your server require more bandwidth.
Might you may not able you open in mobile, Since mobile better work with small amount of data.
https://dba.stackexchange.com/questions/3972/too-many-columns-in-mysql
There is a hard limit of 4096 columns per table, but the effective maximum may be less for a given table. The exact limit depends on several interacting factors.
Every table (regardless of storage engine) has a maximum row size of 65,535 bytes. Storage engines may place additional constraints on this limit, reducing the effective maximum row size.
The maximum row size constrains the number (and possibly size) of columns because the total length of all columns cannot exceed this size.
...
Individual storage engines might impose additional restrictions that limit table column count. Examples:
InnoDB permits up to 1000 columns.
Now my table is in MYISAM because I use FULL TEXT SEARCH.
I have a column in this table thats has text more like a blog post. That column contributes max. to this table's size. This column is not even used in FULL TEXT SEARCH.
About 20-50 rows are inserted in this table every 6 hours. So, most of the time its just reading data from it.
Should I switch to Innodb? Or create another table in Innodb with just 2 columns as massive column and rel. id. Or I should write this column into txt files and access those when needed.
I am totally confused and most of the articles, questions didn't help me much.
Any suggestions on what should I do to improve its performance?
You haven't given enough information to determine any cost versus benefit ratios, or even if the current performance might be reasonable. You can optimize any system indefinitely, but you need to keep in mind Is it now good enough?
The surest answer is to implement all reorganizations and time them. Since there seems to be only one table in question, it should not take more than a few hours of engineering effort, plus whatever time it takes for the imports to run.
If the numbers of the record is very big like N*10 M per table , is there any benefit to move the varchar(2xx) column to a nosql storage? The content of the text won't be very long, I　think 200 characters is big enough. And the engine of mysql will be innoDB. The column won't be used as an index.
Moving a specific column won't help performance much and will likely reduce performance because you need to get data from two places instead of one.
In general the slow part of any query is finding the right record - once you find that record, reading a few hundred bytes more doesn't really change anything.
Also, 10 million records of 200 characters is at most 4GB - not much even if your dataset needs to fit in RAM.
I am wondering at which point would my MySQL table be considered too big.
The table is this:
id
customer_id (int)
value (float)
timestamp_1 (datetime)
tmestampt_2 (datetime)
so the row size is not too great, but would be constantly being added. In my estimation I am looking at around 17000 new rows a day, so about 500,000 a month. The data is likely to be polled quite constantly in large quantities.
Should I be looking at ways to split this or am I still OK at this point?
Thanks,
From http://dev.mysql.com/doc/refman/5.0/en/full-table.html:
The effective maximum table size for MySQL databases is usually determined by operating system constraints on file sizes, not by MySQL internal limits.
From the table in the linked article, on FAT/FAT32 systems and Linux pre 2.4, the maximum file size is 2-4 GB, on all other systems listed, the max file size is at least 2TB.
So long as you index your table correctly, there shouldn't be too much slowdown as your table grows. However, if your table grows to the extent that you do notice any slowdown, it might be an option for you to archive off old records periodically.
What is "Too big" is really going to depend on how big your hardware is. MySQL itself should have no problem managing millions of rows in a table.
Still, I would think about splitting it up to get the best possible performance. Exactly how you do that would depend on how the data is used. Is more recent data used much more frequently? If so, create an archive table with the same structure to store the old data and periodically move data from your main table to the archive table. This would increase the complexity of your application, but could give you better performance in the long run.
It would be too big when your query starts to slow down.
Do you need to keep the entire history in this table or are you only ever looking for the latest values? You could optimise things by archiving off records you don't need onto an archive table.
Other than that, be careful how you plan your indexes. If you put indexes all over the place, inserts may take longer. If you don't have any indexes but need to sort and filter, the retrieval may be too slow.
In MyISAM, the theoretical table size is constrained by the size of data pointer, set by myisam_data_pointer_size.
It can be from 2 to 7 bytes, making the possible table size to be from 2 ^ (8 * 2) = 65k to 2 ^ (8 * 7) = 64P bytes long.
By default, it's 6 bytes (256T).
Of course, since MyISAM tables are held in one file, the maximum size of the file is subject to constraint by the OS and the filesystem.
An InnoDB tablespace can consist of as many as 2^32 pages, which is 4G pages of 16K bytes each, or 64T bytes at most.