Hi, >What's the reason that postgres needs more index pages to store random >data >than sequential ones? I assume that is because B-Tree is self-balanced tree, so it needs to be rebalanced after each insertion. Random insertions may go to the head of index where no space left leading to huge data moving. https://en.wikipedia.org/wiki/B-tree#Insertions_and_deletions Ilya Kazakevich JetBrains http://www.jetbrains.com The Drive to Develop -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general