Postgres95 1.01 Distribution - Virgin Sources

src/bin/pgtclsh/updateStats.tcl

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+#
+# updateStats 
+#   updates the statistic of number of distinct attribute values
+#  (this should really be done by the vacuum command)
+#   this is kind of brute force and slow, but it works
+#  since we use SELECT DISTINCT to calculate the number of distinct values
+# and that does a sort, you need to have plenty of disk space for the 
+# intermediate sort files.
+# 
+# - jolly 6/8/95
+
+#
+# update_attnvals
+#   takes in a table and updates the attnvals columns for the attributes
+# of that table
+#
+#  conn is the database connection
+#  rel is the table name 
+proc update_attnvals {conn rel} {
+    
+   # first, get the oid of the rel
+    set res [pg_exec $conn "SELECT oid FROM pg_class where relname = '$rel'"]
+    if { [pg_result $res -numTuples] == "0"} {
+	puts stderr "update_attnvals: Relation named $rel was not found"
+	return
+    }
+    set oid [pg_result $res -getTuple 0]
+    pg_result $res -clear
+
+    # use this query to find the names of the attributes
+    set res [pg_exec $conn "SELECT * FROM $rel WHERE 'f'::bool"]
+    set attrNames [pg_result $res -attributes]
+
+    puts "attrNames = $attrNames"
+    foreach att $attrNames {
+	# find how many distinct values there are for this attribute
+	# this may fail if the user-defined type doesn't have 
+	# comparison operators defined
+	set res2 [pg_exec $conn "SELECT DISTINCT $att FROM $rel"]
+	set NVALS($att) [pg_result $res2 -numTuples]
+	puts "NVALS($att) is $NVALS($att)"
+	pg_result $res2 -clear
+    }
+    pg_result $res -clear
+
+    # now, update the pg_attribute table
+    foreach att $attrNames {
+	# first find the oid of the row to change
+	set res [pg_exec $conn "SELECT oid FROM pg_attribute a WHERE a.attname = '$att' and a.attrelid = '$oid'"]
+	set attoid [pg_result $res -getTuple 0]
+	set res2 [pg_exec $conn "UPDATE pg_attribute SET attnvals = $NVALS($att) where pg_attribute.oid = '$attoid'::oid"]
+    }
+}
+
+# updateStats
+#    takes in a database name
+# and updates the attnval stat for all the user-defined tables
+# in the database
+proc updateStats { dbName } {
+    # datnames is the list to be result
+    set conn [pg_connect $dbName]
+    set res [pg_exec $conn "SELECT relname FROM pg_class WHERE relkind = 'r' and relname !~ '^pg_' and relname !~ '^Xinv'"]
+    set ntups [pg_result $res -numTuples]
+    for {set i 0} {$i < $ntups} {incr i} {
+	set rel [pg_result $res -getTuple $i]
+	puts "updating attnvals stats on table $rel"
+	update_attnvals $conn $rel
+    }
+    pg_disconnect $conn
+}
+