Methods, systems, and computer-readable media for two-dimensional partition splitting in a time-series database are disclosed. Stream processor(s) write elements of time-series data to a first replica group of a first tile associated with a first set of spatial and temporal boundaries. A second replica group is initialized with the same boundaries. A control plane generates updated metadata for the first tile. The updated metadata indicates a modified first set of spatial and temporal boundaries for the first replica group associated with the first tile and a second set of spatial and temporal boundaries for the second replica group associated with a second tile. The modified first set represents a first portion of the first set, and the second set represents a second portion of the first set. The updated metadata is obtained by the stream processor(s) which write, to the second tile, time-series data within the second set of boundaries.