am using magento 1.9 version in that I'm trying to create some newsletter emails using magentos transaction email system but I've run into situation where when I save the template it cuts off the email at a certain point. Because of the nature of coding everythin in tables and inline css the html is quite large and for one particular email length is 1800 lines and its getting cut off at around 1200 lines for example i say. So my question is: Is there a limit to the size of email templates and if so can it be changed??
Yes there is a limit. And the limit is setted by the column "Newsletter_text" from your "Newsletter_queue" table.
The limit is 65.535 characters because the attribute type is Text. You can set different types for extend the limit, like setting up the column as "Longtext" or "Mediumtext".
Longtext will be able to contain 4.294.967.295 characters, Mediumtext can have a limit of 16.777.215 characters. Depending on your needs, choice the correct type.
I didnt try it yet, but it should work like this.
Related
I have a MariaDB InnoDB table with several million rows, but with short, fixed-width rows consisting of numbers and timestamps only.
We usually search, filter and sort the rows using any of the existing columns.
We want to add a column to store an associated "url" to each row. Ideally every row will have it's url.
We know for a fact that we won't be sorting, searching and filtering by the url column.
We don't mind truncating the URL to it's first 255 bytes, so we are going to give it the VARCHAR type.
But of course that column's width would be variable. The whole record will become variable-width and the width of the original record will double in many cases.
We were considering the alternative of using a different, secondary table for storing the varchar.
We could join them when querying the data, or even more efficiently -probably- just fetch the url's for the page we are showing.
Would this approach be advisable?
Is there a better alternative that would also allow us to preserve performance?
Update: As user Bill Karwin noted in one comment below, InnoDB does not benefit from fixed width as much as MyISAM does, so the real issue here is about the size of the row and not so much about the fixed versus variable width discussion.
Assuming you have control over how the URL is generated, you may want to change it to a fixed-length state. Youtube videos' URIs, for instance, are always 11 characters long and base-64. This fixes the variable length problem and avoids joining tables.
If changing URI generation is not an option, you have a few alternatives to make it fixed-length:
You could fill in the blanks with a special character to force every url to be 255 within the database, and removing it just before returning it. This is not a clean solution but makes DQL operations faster than joining.
You could fetch the url as you have stated, but beware that two http requests may be more time consuming than any other option with just one request.
You could join with another table only when the user requires it, as opposed to it being the default.
Consider that having variable length may not be as big a problem, depending on your needs. The only issue might be if you're grossly oversizing fields, but it doesn't seem to be your case.
FIXED MySQL table has well-known performance advantages over DYNAMIC table.
There is a table tags with only one description TEXT field. An idea is to split this field into 4-8 CHAR(255) fields. For INSERT/UPDATE queries just divide description into chunks (PHP function str_split()). That will make table FIXED.
Have anybody practiced this technique? Is it worth it?
OK, this is done, but where it is done I have only seen it done for historical reasons, such as a particular client-server model that requires it, or for legacy reports where the segments are de facto fields in the layout.
The examples I have seen where for free form text entries (remarks, notes, contact log) in insurance/collections applications and the like where formatting on a printed report was important or there was a need to avoid any confusion in post post processing to dress the format where multiple platforms are involved. (\r\n vs \n and EBCDIC vertical tabs).
So not generally for space/performance/recovery purposes.
If the row is "mostly" this field, a alternative would be to create a row for each segment and add a low-range sequence number to the key.
In this way you would have only 1 row for short values and up to 8 for long. Consider your likely statistics.
Caveats :
Always be acutely aware of MySQL indexes dropping trailing spaces. Concatenating these should take this into account if used in an index.
This is not a recommendation, but "tags" sounds like a candidate for a single varchar field for full text indexing. If the data is so important that forensic recovery is a requirement, then normalising the model to store the tags in a separate table may be another way to go.
On my website, an user can insert a hyperlink in a text input field. Then, this link (a string) is stored in my database.
On MySQL, the field that contains the hyperlink string is TEXT type, but I think its too long for this kind of information. Besides, VARCHAR(255) is too short sometimes.
What's the best type/length to store a hyperlink? It would be nice to know how long a link can be.
There is no limit to how long a hyperlink can be. Browsers limit the amount of data a GET request can send with a hyperlink, but there is no limit on how long the actual link itself can be.
A standard TEXT field will be fine for storing links (you won't suffer a performance hit for using that field as opposed to the VARCHAR(255) field type, nor will you use extra memory, so there's really no reason not to use it.)
See: What is the maximum length of a URL in different browsers?
You could use VARCHAR(2048) if you want a lower limit. There's nothing wrong with using TEXT in terms of space though. In both cases they only use as much space as the text plus a few bytes to represent the length. See Data Type Storage Requirements for details.
As for whether or not you should pick VARCHAR or TEXT see: MySQL: Large VARCHAR vs. TEXT?
HTTP does not specify any limit to the length of URLs. However, webservers and browsers may put a limit.
I guess some old IE versions have a limit of just around 250 characters.
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Closed 11 years ago.
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List of standard lengths for database fields
Simple as that, what should be the typical length of allowed "Full Name" of a user in database?
When I create users table, I usually set it as varchar 31 or 32 (according to performance). What do you guys use and what's standard/typical convention.
Sidenote: I never face problem in email length (as I set it 254) and password (hash, 32 length).
The maximum your average varchar field allows (254?).
You are not winning anything by making it arbitrarily shorter. The fine-grained size controls on numbers and chars are more or less a relic from the past, when every byte mattered. It can matter today - if you are dealing with tens or hundreds of millions of rows, or thousands of queries per sec. For your average database (i.e. 99% of them) performance comes from proper indexing and querying, NOT making your rows a couple of bytes smaller.
Only restrict the length of a field when there is some formal specification that defines a maximum length, like 13 digits for an EAN code or 12 characters for an ISIN.
Full name is always a computed column composed of first, middle, last, prefix, suffix, degree, family name, etc in my designs. The list of individual columns are determined by the targeted local of the app. The display length of 'Full Name' is normall contained within the app design not the database. There is not any space savings in SQL Server between varchar(32) and varchar(256). Varchar(256) is my choice.
I never want to be in the meeting when someone says "Your db design will not hold all our data".
You are always assigning an ID to the user so you can join and do look-ups using the ID instead of the FullName, correct?
I would recommend at least 128.
Well you can just put it at 255 if you want.
varchars is a Variable length storage type. This means theres 1 byte which stores the actual length of the string, varchars dont use up more bites then needed so storage wise it really does not matter. This is described on the mysql page
Description can be found here http://dev.mysql.com/doc/refman/5.0/en/char.html
It is illustrated halfway the page check the table.
VARCHAR values are not padded when
they are stored. Handling of trailing
spaces is version-dependent. As of
MySQL 5.0.3, trailing spaces are
retained when values are stored and
retrieved, in conformance with
standard SQL. Before MySQL 5.0.3,
trailing spaces are removed from
values when they are stored into a
VARCHAR column; this means that the
spaces also are absent from retrieved
values.
Conclusion:
Storage wise you could always go for 255 because it wont use up additional space and you wont get intro trouble with string getting cut off.
Greetz
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Are there disadvantages to using a generic varchar(255) for all text-based fields?
In MYSQL you can choose a length for the VARCHAR field type. Possible values are 1-255.
But what are its advantages if you use VARCHAR(255) that is the maximum instead of VARCHAR(20)? As far as I know, the size of the entries depends only on the real length of the inserted string.
size (bytes) = length+1
So if you have the word "Example" in a VARCHAR(255) field, it would have 8 bytes. If you have it in a VARCHAR(20) field, it would have 8 bytes, too. What is the difference?
I hope you can help me. Thanks in advance!
Check out: Reference for Varchar
In short there isn't much difference unless you go over the size of 255 in your VARCHAR which will require another byte for the length prefix.
The length indicates more of a constraint on the data stored in the column than anything else. This inherently constrains the MAXIMUM storage size for the column as well. IMHO, the length should make sense with respect to the data. If your storing a Social Security # it makes no sense to set the length to 128 even though it doesn't cost you anything in storage if all you actually store is an SSN.
There are many valid reasons for choosing a value smaller than the maximum that are not related to performance. Setting a size helps indicate the type of data you are storing and also can also act as a last-gasp form of validation.
For instance, if you are storing a UK postcode then you only need 8 characters. Setting this limit helps make clear the type of data you are storing. If you chose 255 characters it would just confuse matters.
I don't know about mySQL but in SQL Server it will let you define fields such that the total number of bytes used is greater than the total number of bytes that can actually be stored in a record. This is a bad thing. Sooner or later you will get a row where the limit is reached and you cannot insert the data.
It is far better to design your database structure to consider row size limits.
Additionally yes, you do not want people to put 200 characters in a field where the maximum value should be 10. If they do, it is almost always bad data.
You say, well I can limit that at the application level. But data does not get into the database just from one application. Sometimes multiple applications use it, sometimes data is imported and sometimes it is fixed manually from the query window (update all the records to add 10% to the price for instance). If any of these other sources of data don't know about the rules you put in your application, you will have bad, useless data in your database. Data integrity must be enforced at the database level (which doesn't stop you from also checking before you try to enter data) or you have no integrity. Plus it has been my experience that people who are too lazy to design their database are often also too lazy to actually put the limits into the application and there is no data integrity check at all.
They have a word for databases with no data integrity - useless.
There is a semantical difference (and I believe that's the only difference): if you try to fill 30 non-space characters into varchar(20), it will produce an error, whereas it will succeed for varchar(255). So it is primarily an additional constraint.
Well, if you want to allow for a larger entry, or limit the entry size perhaps.
For example, you may have first_name as a VARCHAR 20, but perhaps street_address as a VARCHAR 50 since 20 may not be enough space. At the same time, you may want to control how large that value can get.
In other words, you have set a ceiling of how large a particular value can be, in theory to prevent the table (and potentially the index/index entries) from getting too large.
You could just use CHAR which is a fixed width as well, but unlike VARCHAR which can be smaller, CHAR pads the values (although this makes for quicker SQL access.
From a database perspective performance wise I do not believe there is going to be a difference.
However, I think a lot of the decision on the length to use comes down to what you are trying to accomplish and documenting the system to accept just the data that it needs.