# Run this TCL script using "testfixture" in order get a report that shows # how much disk space is used by a particular data to actually store data # versus how much space is unused. # # Get the name of the database to analyze # set argv $argv0 if {[llength $argv]!=1} { puts stderr "Usage: $argv0 database-name" exit 1 } set file_to_analyze [lindex $argv 0] if {![file exists $file_to_analyze]} { puts stderr "No such file: $file_to_analyze" exit 1 } if {![file readable $file_to_analyze]} { puts stderr "File is not readable: $file_to_analyze" exit 1 } if {[file size $file_to_analyze]<512} { puts stderr "Empty or malformed database: $file_to_analyze" exit 1 } # Open the database # sqlite3 db [lindex $argv 0] set DB [btree_open [lindex $argv 0] 1000 0] # In-memory database for collecting statistics # sqlite3 mem :memory: set tabledef\ {CREATE TABLE space_used( name clob, -- Name of a table or index in the database file tblname clob, -- Name of associated table is_index boolean, -- TRUE if it is an index, false for a table nentry int, -- Number of entries in the BTree leaf_entries int, -- Number of leaf entries payload int, -- Total amount of data stored in this table or index ovfl_payload int, -- Total amount of data stored on overflow pages ovfl_cnt int, -- Number of entries that use overflow mx_payload int, -- Maximum payload size int_pages int, -- Number of interior pages used leaf_pages int, -- Number of leaf pages used ovfl_pages int, -- Number of overflow pages used int_unused int, -- Number of unused bytes on interior pages leaf_unused int, -- Number of unused bytes on primary pages ovfl_unused int -- Number of unused bytes on overflow pages );} mem eval $tabledef # This query will be used to find the root page number for every table # in the database. # set sql { SELECT name, rootpage FROM sqlite_master WHERE type='table' UNION ALL SELECT 'sqlite_master', 1 ORDER BY 1 } # Quote a string for SQL # proc quote txt { regsub -all ' $txt '' q return '$q' } # Analyze every table in the database, one at a time. # set pageSize [db eval {PRAGMA page_size}] foreach {name rootpage} [db eval $sql] { puts stderr "Analyzing table $name..." set cursor [btree_cursor $DB $rootpage 0] set go [btree_first $cursor] catch {unset seen} set total_payload 0 ;# Payload space used by all entries set total_ovfl 0 ;# Payload space on overflow pages set unused_int 0 ;# Unused space on interior nodes set unused_leaf 0 ;# Unused space on leaf nodes set unused_ovfl 0 ;# Unused space on overflow pages set cnt_ovfl 0 ;# Number of entries that use overflows set cnt_leaf_entry 0 ;# Number of leaf entries set cnt_int_entry 0 ;# Number of interor entries set mx_payload 0 ;# Maximum payload size set ovfl_pages 0 ;# Number of overflow pages used set leaf_pages 0 ;# Number of leaf pages set int_pages 0 ;# Number of interior pages while {$go==0} { incr cnt_leaf_entry set stat [btree_cursor_info $cursor] set payload [lindex $stat 6] if {$payload>$mx_payload} {set mx_payload $payload} incr total_payload $payload set local [lindex $stat 8] set ovfl [expr {$payload-$local}] if {$ovfl} { incr cnt_ovfl incr total_ovfl $ovfl set n [expr {int(ceil($ovfl/($pageSize-4.0)))}] incr ovfl_pages $n incr unused_ovfl [expr {$n*($pageSize-4) - $ovfl}] } set pgno [lindex $stat 0] if {![info exists seen($pgno)]} { set seen($pgno) 1 incr leaf_pages incr unused_leaf [lindex $stat 4] set parent [lindex $stat 9] set up 0 while {$parent!=0 && ![info exists seen($parent)]} { incr up set stat [btree_cursor_info $cursor $up] set seen($parent) 1 incr int_pages incr cnt_int_entry [lindex $stat 2] incr unused_int [lindex $stat 4] set parent [lindex $stat 9] } } set go [btree_next $cursor] } btree_close_cursor $cursor if {[llength [array names seen]]==0} { set leaf_pages 1 set unused_leaf [expr {$pageSize-8}] } elseif {$rootpage==1 && ![info exists seen(1)]} { incr int_pages incr unused_int [expr {$pageSize-112}] } set sql "INSERT INTO space_used VALUES(" append sql [quote $name] append sql ",[quote $name]" append sql ",0" append sql ",[expr {$cnt_leaf_entry+$cnt_int_entry}]" append sql ",$cnt_leaf_entry" append sql ",$total_payload" append sql ",$total_ovfl" append sql ",$cnt_ovfl" append sql ",$mx_payload" append sql ",$int_pages" append sql ",$leaf_pages" append sql ",$ovfl_pages" append sql ",$unused_int" append sql ",$unused_leaf" append sql ",$unused_ovfl" append sql ); mem eval $sql } # This query will be used to find the root page number for every index # in the database. # set sql { SELECT name, tbl_name, rootpage FROM sqlite_master WHERE type='index' ORDER BY 2, 1 } # Analyze every index in the database, one at a time. # set pageSize [db eval {PRAGMA page_size}] foreach {name tbl_name rootpage} [db eval $sql] { puts stderr "Analyzing index $name of table $tbl_name..." set cursor [btree_cursor $DB $rootpage 0] set go [btree_first $cursor] catch {unset seen} set total_payload 0 ;# Payload space used by all entries set total_ovfl 0 ;# Payload space on overflow pages set unused_leaf 0 ;# Unused space on leaf nodes set unused_ovfl 0 ;# Unused space on overflow pages set cnt_ovfl 0 ;# Number of entries that use overflows set cnt_leaf_entry 0 ;# Number of leaf entries set mx_payload 0 ;# Maximum payload size set ovfl_pages 0 ;# Number of overflow pages used set leaf_pages 0 ;# Number of leaf pages while {$go==0} { incr cnt_leaf_entry set stat [btree_cursor_info $cursor] set payload [btree_keysize $cursor] if {$payload>$mx_payload} {set mx_payload $payload} incr total_payload $payload set local [lindex $stat 8] set ovfl [expr {$payload-$local}] if {$ovfl} { incr cnt_ovfl incr total_ovfl $ovfl set n [expr {int(ceil($ovfl/($pageSize-4.0)))}] incr ovfl_pages $n incr unused_ovfl [expr {$n*($pageSize-4) - $ovfl}] } set pgno [lindex $stat 0] if {![info exists seen($pgno)]} { set seen($pgno) 1 incr leaf_pages incr unused_leaf [lindex $stat 4] } set go [btree_next $cursor] } btree_close_cursor $cursor if {[llength [array names seen]]==0} { set leaf_pages 1 set unused_leaf [expr {$pageSize-8}] } set sql "INSERT INTO space_used VALUES(" append sql [quote $name] append sql ",[quote $tbl_name]" append sql ",1" append sql ",$cnt_leaf_entry" append sql ",$cnt_leaf_entry" append sql ",$total_payload" append sql ",$total_ovfl" append sql ",$cnt_ovfl" append sql ",$mx_payload" append sql ",0" append sql ",$leaf_pages" append sql ",$ovfl_pages" append sql ",0" append sql ",$unused_leaf" append sql ",$unused_ovfl" append sql ); mem eval $sql } # Generate a single line of output in the statistics section of the # report. # proc statline {title value {extra {}}} { set len [string length $title] set dots [string range {......................................} $len end] set len [string length $value] set sp2 [string range { } $len end] if {$extra ne ""} { set extra " $extra" } puts "$title$dots $value$sp2$extra" } # Generate a formatted percentage value for $num/$denom # proc percent {num denom {of {}}} { if {$denom==0.0} {return ""} set v [expr {$num*100.0/$denom}] set of {} if {$v==1.0 || $v==0.0 || ($v>1.0 && $v<99.0)} { return [format {%5.1f%% %s} $v $of] } elseif {$v<0.1 || $v>99.9} { return [format {%7.3f%% %s} $v $of] } else { return [format {%6.2f%% %s} $v $of] } } # Generate a subreport that covers some subset of the database. # the $where clause determines which subset to analyze. # proc subreport {title where} { global pageSize set hit 0 mem eval " SELECT sum(nentry) AS nentry, sum(leaf_entries) AS nleaf, sum(payload) AS payload, sum(ovfl_payload) AS ovfl_payload, max(mx_payload) AS mx_payload, sum(ovfl_cnt) as ovfl_cnt, sum(leaf_pages) AS leaf_pages, sum(int_pages) AS int_pages, sum(ovfl_pages) AS ovfl_pages, sum(leaf_unused) AS leaf_unused, sum(int_unused) AS int_unused, sum(ovfl_unused) AS ovfl_unused FROM space_used WHERE $where" {} {set hit 1} if {!$hit} {return 0} puts "" set len [string length $title] incr len 5 set stars "***********************************" append stars $stars set stars [string range $stars $len end] puts "*** $title $stars" puts "" set total_pages [expr {$leaf_pages+$int_pages+$ovfl_pages}] statline "Percentage of total database" [percent $total_pages $::file_pgcnt] statline "Number of entries" $nleaf set total_unused [expr {$ovfl_unused+$int_unused+$leaf_unused}] set storage [expr {$total_pages*$pageSize}] statline "Bytes of storage consumed" $storage statline "Bytes of payload" $payload \ [percent $payload $storage {of storage consumed}] statline "Average payload per entry" [expr {$nleaf>0?$payload/$nleaf:0}] set avgunused [expr {$nleaf>0?$total_unused/$nleaf:0}] statline "Average unused bytes per entry" $avgunused set nint [expr {$nentry-$nleaf}] if {$int_pages>0} { statline "Average fanout" [format %.2f [expr {($nint+0.0)/$int_pages}]] } statline "Maximum payload per entry" $mx_payload statline "Entries that use overflow" $ovfl_cnt \ [percent $ovfl_cnt $nleaf {of all entries}] if {$int_pages>0} { statline "Index pages used" $int_pages } statline "Primary pages used" $leaf_pages statline "Overflow pages used" $ovfl_pages statline "Total pages used" $total_pages if {$int_unused>0} { statline "Unused bytes on index pages" $int_unused \ [percent $int_unused [expr {$int_pages*$pageSize}] {of index space}] } statline "Unused bytes on primary pages" $leaf_unused \ [percent $leaf_unused [expr {$leaf_pages*$pageSize}] {of primary space}] statline "Unused bytes on overflow pages" $ovfl_unused \ [percent $ovfl_unused [expr {$ovfl_pages*$pageSize}] {of overflow space}] statline "Unused bytes on all pages" $total_unused \ [percent $total_unused $storage {of all space}] return 1 } # Output summary statistics: # puts "/** Disk-Space Utilization Report For $file_to_analyze" puts "*** As of [clock format [clock seconds] -format {%Y-%b-%d %H:%M:%S}]" puts "" statline {Page size in bytes} $pageSize set fsize [file size $file_to_analyze] set file_pgcnt [expr {$fsize/$pageSize}] set usedcnt [mem eval \ {SELECT sum(leaf_pages+int_pages+ovfl_pages) FROM space_used}] set freecnt [expr {$file_pgcnt-$usedcnt}] set freecnt2 [lindex [btree_get_meta $DB] 0] statline {Pages in the whole file (measured)} $file_pgcnt set file_pgcnt2 [expr {$usedcnt+$freecnt2}] statline {Pages in the whole file (calculated)} $file_pgcnt2 statline {Pages that store data} $usedcnt [percent $usedcnt $file_pgcnt] statline {Pages on the freelist (per header)}\ $freecnt2 [percent $freecnt2 $file_pgcnt] statline {Pages on the freelist (calculated)}\ $freecnt [percent $freecnt $file_pgcnt] set ntable [db eval {SELECT count(*)+1 FROM sqlite_master WHERE type='table'}] statline {Number of tables in the database} $ntable set nindex [db eval {SELECT count(*) FROM sqlite_master WHERE type='index'}] set autoindex [db eval {SELECT count(*) FROM sqlite_master WHERE type='index' AND name LIKE '(% autoindex %)'}] set manindex [expr {$nindex-$autoindex}] statline {Number of indices} $nindex statline {Number of named indices} $manindex statline {Automatically generated indices} $autoindex set total_payload [mem eval "SELECT sum(payload) FROM space_used"] statline "Size of the file in bytes" $fsize set user_payload [mem one {SELECT sum(payload) FROM space_used WHERE NOT is_index AND name NOT LIKE 'sqlite_master'}] statline "Bytes of user payload stored" $user_payload \ [percent $user_payload $fsize] # Output table rankings # puts "" puts "*** Page counts for all tables with their indices ********************" puts "" mem eval {SELECT tblname, count(*) AS cnt, sum(int_pages+leaf_pages+ovfl_pages) AS size FROM space_used GROUP BY tblname ORDER BY size DESC, tblname} {} { statline [string toupper $tblname] $size [percent $size $file_pgcnt] } # Output subreports # if {$nindex>0} { subreport {All tables and indices} 1 } subreport {All tables} {NOT is_index} if {$nindex>0} { subreport {All indices} {is_index} } foreach tbl [mem eval {SELECT name FROM space_used WHERE NOT is_index ORDER BY name}] { regsub ' $tbl '' qn set name [string toupper $tbl] set n [mem eval "SELECT count(*) FROM space_used WHERE tblname='$qn'"] if {$n>1} { subreport "Table $name and all its indices" "tblname='$qn'" subreport "Table $name w/o any indices" "name='$qn'" subreport "Indices of table $name" "tblname='$qn' AND is_index" } else { subreport "Table $name" "name='$qn'" } } # Output instructions on what the numbers above mean. # puts { *** Definitions ****************************************************** Page size in bytes The number of bytes in a single page of the database file. Usually 1024. Number of pages in the whole file } puts \ " The number of $pageSize-byte pages that go into forming the complete database" puts \ { Pages that store data The number of pages that store data, either as primary B*Tree pages or as overflow pages. The number at the right is the data pages divided by the total number of pages in the file. Pages on the freelist The number of pages that are not currently in use but are reserved for future use. The percentage at the right is the number of freelist pages divided by the total number of pages in the file. Number of tables in the database The number of tables in the database, including the SQLITE_MASTER table used to store schema information. Number of indices The total number of indices in the database. Number of named indices The number of indices created using an explicit CREATE INDEX statement. Automatically generated indices The number of indices used to implement PRIMARY KEY or UNIQUE constraints on tables. Size of the file in bytes The total amount of disk space used by the entire database files. Bytes of user payload stored The total number of bytes of user payload stored in the database. The schema information in the SQLITE_MASTER table is not counted when computing this number. The percentage at the right shows the payload divided by the total file size. Percentage of total database The amount of the complete database file that is devoted to storing information described by this category. Number of entries The total number of B-Tree key/value pairs stored under this category. Bytes of storage consumed The total amount of disk space required to store all B-Tree entries under this category. The is the total number of pages used times the pages size. Bytes of payload The amount of payload stored under this category. Payload is the data part of table entries and the key part of index entries. The percentage at the right is the bytes of payload divided by the bytes of storage consumed. Average payload per entry The average amount of payload on each entry. This is just the bytes of payload divided by the number of entries. Average unused bytes per entry The average amount of free space remaining on all pages under this category on a per-entry basis. This is the number of unused bytes on all pages divided by the number of entries. Maximum payload per entry The largest payload size of any entry. Entries that use overflow The number of entries that user one or more overflow pages. Total pages used This is the number of pages used to hold all information in the current category. This is the sum of index, primary, and overflow pages. Index pages used This is the number of pages in a table B-tree that hold only key (rowid) information and no data. Primary pages used This is the number of B-tree pages that hold both key and data. Overflow pages used The total number of overflow pages used for this category. Unused bytes on index pages The total number of bytes of unused space on all index pages. The percentage at the right is the number of unused bytes divided by the total number of bytes on index pages. Unused bytes on primary pages The total number of bytes of unused space on all primary pages. The percentage at the right is the number of unused bytes divided by the total number of bytes on primary pages. Unused bytes on overflow pages The total number of bytes of unused space on all overflow pages. The percentage at the right is the number of unused bytes divided by the total number of bytes on overflow pages. Unused bytes on all pages The total number of bytes of unused space on all primary and overflow pages. The percentage at the right is the number of unused bytes divided by the total number of bytes. } # Output the database # puts "**********************************************************************" puts "The entire text of this report can be sourced into any SQL database" puts "engine for further analysis. All of the text above is an SQL comment." puts "The data used to generate this report follows:" puts "*/" puts "BEGIN;" puts $tabledef unset -nocomplain x mem eval {SELECT * FROM space_used} x { puts -nonewline "INSERT INTO space_used VALUES" set sep ( foreach col $x(*) { set v $x($col) if {$v=="" || ![string is double $v]} {set v [quote $v]} puts -nonewline $sep$v set sep , } puts ");" } puts "COMMIT;"