I am using fuzzystrmatch extension in Postgresql 14.
When I am running below query, it is giving this error message:
ERROR: levenshtein argument exceeds maximum length of 255 characters
SELECT levenshtein('xxxxxxxx', 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYYY');
Referred this document, https://www.postgresql.org/docs/current/fuzzystrmatch.html
which says, that Both source and target can be any non-null string, with a maximum of 255 characters.
But I have this requirement to support any number of characters for levenshtein. Is there any way, I can update this max length in Postgresql for levenshtein?
I referred few Postgresql and fuzzystrmatch documents which says that we can't have more than 255 characters.
https://www.postgresql.org/docs/current/fuzzystrmatch.html
But I am looking for a way, if this max length can be controlled in Postgresql.
Related
What is the maximum number of returned expressions allowed in a PostgreSQL SELECT statement?
(Not to be confused with the maximum number of columns in a table.)
I found it programmatically: 1664 (version 13).
The limit is a bit higher that the column limit of 1600. This is the error that I get when crossing the limit:
ERROR: target lists can have at most 1664 entries
The limit is defined in "src/include/access/htup_details.h" (MaxTupleAttributeNumber 1664) next to the column-amount limit (MaxHeapAttributeNumber 1600). The reason for the difference between the two limits is unclear to me.
I was doing some tests on Postgres using the tinyint extension when I came across something surprising regarding its range. On typing select -128::tinyint it gave me an ERROR: tinyint out of range message which was not what I was expecting at all.
Assuming negative numbers should be 1 greater (or is it less) than the positive maximum (127 for single byte integers) I thought it was a bug with the extension, however on trying this with non-extended numbers I found exactly the same thing was happening.
select -32768::smallint -> out of range
select -2147483648::integer -> out of range
select -9223372036854775808::bigint -> out of range
Referring to the numeric data type documentation (https://www.postgresql.org/docs/current/datatype-numeric.html)
these numbers should all be possible - all negative numbers one less -32767, -2147483647, -9223372036854775807 work correctly so I am curious as to why this is happening, or does this even happen with other peoples copies.
I tried using both postgresql 10 and postgresql 11 on a ubuntu 16.x desktop.
I think this is because the cast operator :: has a higher precedence that the minus sign.
So -32768::smallint is executed as -1 * 32768::smallint which indeed is invalid.
Using parentheses fixes this: (-32768)::smallint or using the SQL standard cast() operator: cast(-32768 as smallint)
I am running a migration script from MYSQL database to PostgreSQL. A new relationship has been recently created on MYSQL which breaks the import to PostgreSQL.
Error: sqlalchemy.exc.IdentifierError: Identifier 'index name' exceeds maximum length of 63 characters
Is there a way to truncate the identifier name or alternatively increase the maximum characters limit label length (table name, column name, index) in PostgreSQL to by-pass this limitation?
I found this excerpt from the postgresql documention:
The system uses no more than NAMEDATALEN-1 bytes of an identifier; longer names can be written in commands, but they will be truncated. By default, NAMEDATALEN is 64 so the maximum identifier length is 63 bytes. If this limit is problematic, it can be raised by changing the NAMEDATALEN constant in src/include/pg_config_manual.h.
Has anyone tried it out? Is there a better solution? I'm using sqlalchemy and python, is there a way of truncating the identifier in Sqlaclchemy?
I'm migrating from MySQL to PostgreSQL because Oracle. There is a great MySQL text type reference, here is the relevant information for MySQL...
CHAR( ) A fixed section from 0 to 255 characters long.
VARCHAR( ) A variable section from 0 to 255 characters long.
TINYTEXT A string with a maximum length of 255 characters.
TEXT A string with a maximum length of 65535 characters.
BLOB A string with a maximum length of 65535 characters.
MEDIUMTEXT A string with a maximum length of 16777215 characters.
MEDIUMBLOB A string with a maximum length of 16777215 characters.
LONGTEXT A string with a maximum length of 4294967295 characters.
LONGBLOB A string with a maximum length of 4294967295 characters.
PostgreSQL seems a bit different, there is a text type looking through phppgAdmin, not sure what else there is and I'm not finding any good comparison tables.
What are all the available text types in PostgreSQL?
PostgreSQL has more advanced types but doesn't need the distinction between text sizes.
There are 3 string types in PostgreSQL and a binary type:
text
Just a text object with a non-specified size. You can put anything in here and it will be stored. Size doesn't matter.
varchar(n) / character varying(n)
Basically a text which has a size check, there is virtually no (except for checking the size while inserting) performance difference here.
char(n) / character(n)
Just a text where all the extra characters will be padded with space characters so you always get n characters back.
bytea
The blob type you've mentioned is a totally different type alltogether. You could replace it with the bytea type: http://www.postgresql.org/docs/9.3/static/datatype-binary.html
Source: http://www.postgresql.org/docs/9.3/static/datatype-character.html
I'm a Firebird newbie here. I'm trying to use Firebird Embedded from an ASP.Net application. Everything connects fine but I'm running into problems with the length of column names. I'm trying to create a table named "Orchard_Framework_DataMigrationRecord." I keep getting an exception which says "Name longer than database column size." After some investigation, I've seen that a number of people have mentioned that Firebird has a column name length limit of 30 characters.
Is that correct and if so is there any way to change it? In my case, I can't change the name of the table; it really has to be that long.
Unfortunately there is no way to change the maximum identifier length, it's an implementation limit. There is a plan to remove this limitation but in current version (2.5) the max identifier length is 31 characters.
This appears to be fixed as of Firebird version 4.0 Alpha 1: Increase maximum length of object names to 63 characters