What is the PostgreSQL field type for Unix epoch time?

The PostgreSQL field type best suited for storing Unix epoch time (the number of seconds that have elapsed since January 1, 1970, at 00:00:00 Coordinated Universal Time (UTC)) is the bigint type. Here's why:

1. Integer Representation: Unix epoch time is an integer value representing seconds. Therefore, a numeric type is required to store it.

2. Range of `bigint`: The bigint data type is a 64-bit integer, capable of storing a wide range of integer values, which is crucial as the Unix epoch time keeps growing. A regular integer (int or integer) might not be sufficient as epoch times increase over the years. bigint provides a much broader range, ensuring that your data storage will accommodate the increasing values well into the future.

3. Alternatives and Why They Aren't Ideal:

- While you could technically store epoch time as text (TEXT or VARCHAR), this is strongly discouraged. Storing numeric data as text makes it difficult to perform calculations, indexing, or comparisons efficiently. It also wastes storage space.

- The timestamp or timestamptz types in PostgreSQL represent a date and time rather than the raw epoch time. While you can convert between timestamp and epoch values, storing the epoch time directly as a number is more straightforward for many applications, especially when you are dealing with timestamps from other systems or programming languages.

4. Best Practice: Using bigint to store Unix epoch time is considered a best practice in PostgreSQL. It’s efficient, provides a large enough range, and ensures optimal performance when querying your database.

5. Example: To create a table with a field to store epoch time:

CREATE TABLE my_table (
  id SERIAL PRIMARY KEY,
  epoch_time BIGINT
);

In summary, for storing Unix epoch time in PostgreSQL, the most suitable field type is bigint due to its numerical representation, sufficient range, and efficiency.

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