Steve Crawford <scrawford@xxxxxxxxxxxxxxxxxxxx> writes: > Alvaro Herrera wrote: >> Of course, the main problem with CLUSTER is that it needs about 2x the >> disk space of table + indexes. >> > Again checking my mental model. My understanding is that CLUSTER > basically recreates the tables and indexes and then swaps the new ones > in place of the originals. So ~2x is true for typical tables. But for > tables badly bloated by multiple bulk updates or bad vacuum practices > CLUSTER should require far less than 2x. Another point to keep in mind is that creation of a new btree index (and, soon, a new hash index) involves a temporary sort file that's roughly the size of the index. So the peak transient space demand is size of compacted table + size of compacted indexes + size of largest index, more or less. (I suppose it'd depend on the order in which the indexes get rebuilt.) regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
