This Los Angeles Times story explains that almost 4,000,000 Californians live in areas with no State Senate representation, due to redistricting and the fact that California, like most states with four-year State Senate terms, doesn’t elect the entire State Senate in years following redistricting.
A few states that don’t normally elect more than half their State Senators in any given year make exceptions for years after redistricting, and elect the entire State Senate. And many states have two-year State Senate terms.