Thread: how to get the height of index tree?
Hi, how to get the height of R* or B tree of created index ?
what's the base of loga(n) function ? is that base a=16? or something else? how to know this base ?
2010/10/22 sunpeng <bluevaley@gmail.com>
Hi, how to get the height of R* or B tree of created index ?
On 10/22/10 11:50 AM, sunpeng wrote: > what's the base of log_/a/ (/n/) function ? is that base a=16? or > something else? how to know this base ? > > 2010/10/22 sunpeng <bluevaley@gmail.com <mailto:bluevaley@gmail.com>> > > Hi, how to get the height of R* or B tree of created index ? > > it would be based on how many index values plus overhead fits in each 8K block. highly variable if the field being indexed is TEXT or VARCHAR or similar.
John R Pierce <pierce@hogranch.com> writes: >> 2010/10/22 sunpeng <bluevaley@gmail.com <mailto:bluevaley@gmail.com>> >> >> Hi, how to get the height of R* or B tree of created index ? You could use Gevel for GiST and GIN: http://www.sai.msu.su/~megera/wiki/Gevel Don't know if something similar exists for btree, but I guess it would be very useful. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support