On Fri, Jan 19, 2024 at 11:37 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
Ron Johnson <ronljohnsonjr@gmail.com> writes: > On an RDMS which I used in the 1990s and 2000s, b-tree indices of sequences > would get unbalanced, since every new leaf was added to the far right > corner of the tree. > Sure, they would auto-balance *to a degree* during node splits, but all > those "far-right corner" inserts still left them pretty lopsided. > Thus, they provided a utility which we could use to determine the > lopsidedness, and thus decide when to rebuild an index.
> Does Postgresql keep b-tree indexes on sequences fully balanced? If not, > how do I see how unbalanced they are? (Assume PG12+.)
As far as I know, we don't have a problem of that sort. Continued insertions will eventually force a split of the root node, which will rebalance the tree.