rdelaage
/
postgresql
mirror of https://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

This patch fixes an incorrect statement and makes a few cleanups to 

contrib/fulltextindex/README.fti

Backpatched to 7.3.X too.

Neil Conway
This commit is contained in:
Bruce Momjian 2003-01-15 16:45:17 +00:00
parent 3b6ca54cda
commit d14c64c4a3
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
contrib/fulltextindex/README.fti
View File

@ -13,11 +13,10 @@ Ofcourse we can write this as:
But this does not use any indices, and therefore, if your database
gets very large, it will not have very high performance (the above query
requires at least one sequential scan, it probably takes 2 due to the
self-join).
requires a sequential scan of the table).
The approach used by this add-on is to define a trigger on the table and
columns you want to do this queries on. On every insert in the table, it
columns you want to do these queries on. On every insert to the table, it
takes the value in the specified columns, breaks the text in these columns
up into pieces, and stores all sub-strings into another table, together
with a reference to the row in the original table that contained this
@ -27,7 +26,7 @@ By now creating an index over the 'fti-table', we can search for
substrings that occur in the original table. By making a join between
the fti-table and the orig-table, we can get the actual rows we want
(this can also be done by using subselects - but subselects are currently
inefficient in Postgres, and maybe there're other ways too).
inefficient in PostgreSQL, and maybe there're other ways too).
The trigger code also allows an array called StopWords, that prevents
certain words from being indexed.