I have a table with five Boolean columns. In 90% plus of the rows, all the columns are null. (
False is equivalent to
null for me.)
Instead of having Boolean columns, I could have a single array column which contains an array of an enumerated custom datatype, and thereby store only the columns which are non-null.
I feel weird using arrays, but my coworker has pointed out to me that there isn't really a strong reason against using them, and we might actually see savings from using them since we aren't storing a bunch of empty columns.
Are there any downsides to using an array? Specifically: would they take up more space, take up more time to query, or prevent Postgres features (e.g. gin indexes) from being used?