Update documentation mention of VACUUM FULL and CLUSTER where

appropriate.

Guillaume Cottenceau

diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index de8df507eac9cf9894eade3fc9460f5b3127e57f..d0e2ef57e68244cf5301562574c7b950e64e13a4 100644 (file)
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -1,4 +1,4 @@
-
+
 
 
  Routine Database Maintenance Tasks
@@ -157,7 +157,8 @@
     command. This uses a more aggressive algorithm for reclaiming the
     space consumed by dead row versions. Any space that is freed by
     VACUUM FULL is immediately returned to the
-    operating system. Unfortunately, this variant of the
+    operating system, and the table data is physically compacted on
+    the disk. Unfortunately, this variant of the
     VACUUM command acquires an exclusive lock on
     each table while VACUUM FULL is processing
     it. Therefore, frequently using VACUUM FULL can
@@ -168,12 +169,16 @@
    
     The standard form of VACUUM is best used with the goal
     of maintaining a fairly level steady-state usage of disk space. If
-    you need to return disk space to the operating system you can use
+    you need to return disk space to the operating system, you can use
     VACUUM FULL — but what's the point of releasing disk
     space that will only have to be allocated again soon?  Moderately
     frequent standard VACUUM runs are a better approach
     than infrequent VACUUM FULL runs for maintaining
-    heavily-updated tables.
+    heavily-updated tables. However, if some heavily-updated tables
+    have gone too long with infrequent VACUUM, you can
+    use VACUUM FULL or CLUSTER to get performance
+    back (it is much slower to scan a table containing almost only dead
+    rows).
    
 
    

diff --git a/doc/src/sgml/ref/vacuum.sgml b/doc/src/sgml/ref/vacuum.sgml
index a2c45b5a0c7933105d36d26620115dd07b051fd6..60bd2ff73e70a7f22ef3bf88d4f3b81bbe4c72d4 100644 (file)
--- a/doc/src/sgml/ref/vacuum.sgml
+++ b/doc/src/sgml/ref/vacuum.sgml
@@ -1,5 +1,5 @@
 
 
@@ -164,10 +164,11 @@ VACUUM [ FULL ] [ FREEZE ] [ VERBOSE ] ANALYZE [ 
    
     The FULL option is not recommended for routine use,
     but might be useful in special cases.  An example is when you have deleted
-    most of the rows in a table and would like the table to physically shrink
-    to occupy less disk space.  VACUUM FULL will usually
-    shrink the table more than a plain VACUUM would.
-    The FULL option does not shrink indexes; a periodic
+    or updated most of the rows in a table and would like the table to
+    physically shrink to occupy less disk space and allow faster table
+    scans. VACUUM FULL will usually shrink the table
+    more than a plain VACUUM would.  The
+    FULL option does not shrink indexes; a periodic
     REINDEX is still recommended.  In fact, it is often faster
     to drop all indexes, VACUUM FULL, and recreate the indexes.