112 lines
3.3 KiB
Tcl
112 lines
3.3 KiB
Tcl
# Run this TCL script using "testfixture" in order get a report that shows
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# how much disk space is used by a particular data to actually store data
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# versus how much space is unused.
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#
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# Get the name of the database to analyze
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#
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if {[llength $argv]!=1} {
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puts stderr "Usage: $argv0 database-name"
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exit 1
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}
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set file_to_analyze [lindex $argv 0]
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# Open the database
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#
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sqlite db [lindex $argv 0]
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set DB [btree_open [lindex $argv 0]]
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# Output the schema for the generated report
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#
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puts \
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{BEGIN;
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CREATE TABLE space_used(
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name clob, -- Name of a table or index in the database file
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is_index boolean, -- TRUE if it is an index, false for a table
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payload int, -- Total amount of data stored in this table or index
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pri_pages int, -- Number of primary pages used
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ovfl_pages int, -- Number of overflow pages used
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pri_unused int, -- Number of unused bytes on primary pages
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ovfl_unused int -- Number of unused bytes on overflow pages
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);}
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# This query will be used to find the root page number for every index and
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# table in the database.
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#
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set sql {
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SELECT name, type, rootpage FROM sqlite_master
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UNION ALL
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SELECT 'sqlite_master', 'table', 2
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ORDER BY 1
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}
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# Initialize variables used for summary statistics.
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#
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set total_size 0
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set total_primary 0
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set total_overflow 0
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set total_unused_primary 0
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set total_unused_ovfl 0
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# Analyze every table in the database, one at a time.
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#
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foreach {name type rootpage} [db eval $sql] {
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set cursor [btree_cursor $DB $rootpage 0]
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set go [btree_first $cursor]
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set size 0
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catch {unset pg_used}
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set unused_ovfl 0
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set n_overflow 0
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while {$go==0} {
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set payload [btree_payload_size $cursor]
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incr size $payload
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set stat [btree_cursor_dump $cursor]
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set pgno [lindex $stat 0]
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set freebytes [lindex $stat 4]
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set pg_used($pgno) $freebytes
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if {$payload>238} {
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set n [expr {($payload-238+1019)/1020}]
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incr n_overflow $n
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incr unused_ovfl [expr {$n*1020+238-$payload}]
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}
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set go [btree_next $cursor]
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}
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btree_close_cursor $cursor
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set n_primary [llength [array names pg_used]]
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set unused_primary 0
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foreach x [array names pg_used] {incr unused_primary $pg_used($x)}
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regsub -all ' $name '' name
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puts -nonewline "INSERT INTO space_used VALUES('$name'"
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puts -nonewline ",[expr {$type=="index"}]"
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puts ",$size,$n_primary,$n_overflow,$unused_primary,$unused_ovfl);"
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incr total_size $size
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incr total_primary $n_primary
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incr total_overflow $n_overflow
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incr total_unused_primary $unused_primary
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incr total_unused_ovfl $unused_ovfl
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}
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# Output summary statistics:
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#
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puts "-- Total payload size: $total_size"
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puts "-- Total pages used: $total_primary primary and $total_overflow overflow"
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set file_pgcnt [expr {[file size [lindex $argv 0]]/1024}]
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puts -nonewline "-- Total unused bytes on primary pages: $total_unused_primary"
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if {$total_primary>0} {
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set upp [expr {$total_unused_primary/$total_primary}]
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puts " (avg $upp bytes/page)"
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} else {
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puts ""
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}
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puts -nonewline "-- Total unused bytes on overflow pages: $total_unused_ovfl"
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if {$total_overflow>0} {
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set upp [expr {$total_unused_ovfl/$total_overflow}]
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puts " (avg $upp bytes/page)"
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} else {
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puts ""
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}
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set n_free [expr {$file_pgcnt-$total_primary-$total_overflow}]
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if {$n_free>0} {incr n_free -1}
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puts "-- Total pages on freelist: $n_free"
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puts "COMMIT;"
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