Linked Questions

I have a PostgreSQL table. select * is very slow whereas select id is nice and quick. I think it may be that the size of the row is very large and it's taking a while to transport, or it may be some ...

Our system writes a lots of data (kind of Big Data system). Write performance is good enough for our needs but read performance is really too slow. The primary key (constraint) structure is similar ...

I am developing an application in Ruby on Rails with the PostgreSQL (9.4) database. For my use case, columns in tables will be looked up very frequently, as the whole point of the application is ...

I have a legacy schema (disclaimer!) that uses a hash-based generated id for the primary key for all tables (there are many). An example of such an id is: 922475bb-ad93-43ee-9487-d2671b886479 There ...

In this answer (https://stackoverflow.com/questions/517579/strings-as-primary-keys-in-sql-database) a single remark caught my eye: Also keep in mind that there's often a very big difference between ...

In PostgreSQL documentation, it is said that integer data types can be stored in either two-, four- or eight-byte space. One of the columns of a table in my database contains a one-byte integer value ...

What is the difference between the smallint type and the bool type for storing boolean values? This question arose in the comments to a question on Geographic Information Systems Stack Exchange.

I'm working on a project that is using the instagram key format. TL;DR 64-bit integer ids. They'll be used for lookups, and we also like them for sorting and batching since they will naturally sort ...

We have repeatedly seen failing attempts to index columns with values exceeding a maximum size. Postgres 10 has this kind of error message for it: ERROR: index row size xxxx exceeds maximum 2712 for ...

Problem I plan to load a CSV with more 10 million records into PostgreSQL v12.1, one of its columns has "categorical" values, so creating an enumerated type for it seems to be a good choice, but it ...

I have a short question concerning my database size. I need to insert data in a database. Before the insert, some calculations need to be done. The point is: from 50 mb plain data (~700,000 lines), ...

I have an analytics database on Postgres 9.5 I'm taking advantage of constraint partitioning with table inheritance to split up events into monthly tables. The base (parent) table contains no rows. I ...

When I use varchar(5) in a INSERT query it means that the attribute in the table will take exactly 5 bytes in memory? (Given that one printable character takes one byte)?

I read this excellent answer on optimal column ordering and noticed the summation: Generally speaking, if you put the 8-byte-types first then the 4-byte-types and the 2-byte-types last you can't go ...

I have a sparse matrix table where every attribute is citext. There are some indexes built against a few of the fields. I want to change these columns back to varchar. Can I do this against a live ...