"Guillaume Smet" <guillaume.smet@xxxxxxxxx> writes: > I experienced this morning a performance problem when we imported a > dump in a 8.1 database. > The table is 5 millions rows large and when the dump creates an index > on a specific text column called clazz it takes 27 minutes while on > the other columns, it only takes a couple of seconds: > The only weird thing about this column is that 4.7 millions of rows > have the exact same value. Do you have maintenance_work_mem set large enough that the index creation sort is done in-memory? 8.1 depends on the platform's qsort and a lot of them are kinda pessimal for input like this. 8.2 (which uses our own qsort) seems to perform better in a quick test. regards, tom lane
