SQLite

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

# Create a temporary "dbstat" virtual table.
#
db eval {CREATE VIRTUAL TABLE temp.stat USING dbstat}
db eval {CREATE TEMP TABLE dbstat AS SELECT * FROM temp.stat
         ORDER BY name, path}
db eval {DROP TABLE temp.stat}

proc isleaf {pagetype is_index} {
  return [expr {$pagetype == "leaf" || ($pagetype == "internal" && $is_index)}]
}
proc isoverflow {pagetype is_index} {
  return [expr {$pagetype == "overflow"}]
}
proc isinternal {pagetype is_index} {
  return [expr {$pagetype == "internal" && $is_index==0}]
}

db func isleaf isleaf
db func isinternal isinternal
db func isoverflow isoverflow

set isCompressed 0
set compressOverhead 0

set sql { SELECT name, tbl_name FROM sqlite_master WHERE rootpage>0 }
foreach {name tblname} [concat sqlite_master sqlite_master [db eval $sql]] {

  set is_index [expr {$name!=$tblname}]
  set idx_btree [expr {$is_index || [is_without_rowid $name]}]
  db eval {
    SELECT 
      sum(ncell) AS nentry,
      sum(isleaf(pagetype, $idx_btree) * ncell) AS leaf_entries,
      sum(payload) AS payload,
      sum(isoverflow(pagetype, $idx_btree) * payload) AS ovfl_payload,
      sum(path LIKE '%+000000') AS ovfl_cnt,
      max(mx_payload) AS mx_payload,
      sum(isinternal(pagetype, $idx_btree)) AS int_pages,
      sum(isleaf(pagetype, $idx_btree)) AS leaf_pages,
      sum(isoverflow(pagetype, $idx_btree)) AS ovfl_pages,
      sum(isinternal(pagetype, $idx_btree) * unused) AS int_unused,
      sum(isleaf(pagetype, $idx_btree) * unused) AS leaf_unused,
      sum(isoverflow(pagetype, $idx_btree) * unused) AS ovfl_unused,
      sum(pgsize) AS compressed_size


    FROM temp.dbstat WHERE name = $name
  } break

  set total_pages [expr {$leaf_pages+$int_pages+$ovfl_pages}]
  set storage [expr {$total_pages*$pageSize}]
  if {!$isCompressed && $storage>$compressed_size} {
    set isCompressed 1

  mem eval {
    INSERT INTO space_used VALUES(
      $name,
      $tblname,
      $is_index,
      $nentry,
      $leaf_entries,

      $payload,     
      $ovfl_payload,
      $ovfl_cnt,   
      $mx_payload,
      $int_pages,
      $leaf_pages,  
      $ovfl_pages, 

      int(sum(leaf_pages)) AS leaf_pages,
      int(sum(int_pages)) AS int_pages,
      int(sum(ovfl_pages)) AS ovfl_pages,
      int(sum(leaf_unused)) AS leaf_unused,
      int(sum(int_unused)) AS int_unused,
      int(sum(ovfl_unused)) AS ovfl_unused,
      int(sum(gap_cnt)) AS gap_cnt,
      int(sum(compressed_size)) AS compressed_size


    FROM space_used WHERE $where" {} {}

  # Output the sub-report title, nicely decorated with * characters.
  #
  puts ""
  titleline $title
  puts ""

    set nTab [mem eval "
      SELECT count(*) FROM (
          SELECT DISTINCT tblname FROM space_used WHERE $where AND is_index=0
      )
    "]
    set avg_fanout [mem eval "
      SELECT (sum(leaf_pages+int_pages)-$nTab)/sum(int_pages) FROM space_used
          WHERE $where AND is_index = 0
    "]
    set avg_fanout [format %.2f $avg_fanout]
  }
  set ovfl_cnt_percent [percent $ovfl_cnt $nleaf {of all entries}]

  # Print out the sub-report statistics.
  #
  statline {Percentage of total database} $total_pages_percent
  statline {Number of entries} $nleaf
  statline {Bytes of storage consumed} $storage
  if {$compressed_size!=$storage} {
    set compressed_size [expr {$compressed_size+$compressOverhead*$total_pages}]
    set pct [expr {$compressed_size*100.0/$storage}]
    set pct [format {%5.1f%%} $pct]
    statline {Bytes used after compression} $compressed_size $pct
  }
  statline {Bytes of payload} $payload $payload_percent

  statline {Average payload per entry} $avg_payload
  statline {Average unused bytes per entry} $avg_unused
  if {[info exists avg_fanout]} {
    statline {Average fanout} $avg_fanout
  }
  if {$showFrag && $total_pages>1} {
    set fragmentation [percent $gap_cnt [expr {$total_pages-1}]]