SQLite

  "  name       STRING,           /* Name of table or index */"             \
  "  path       INTEGER,          /* Path to page from root */"             \
  "  pageno     INTEGER,          /* Page number */"                        \
  "  pagetype   STRING,           /* 'internal', 'leaf' or 'overflow' */"   \
  "  ncell      INTEGER,          /* Cells on page (0 for overflow) */"     \
  "  payload    INTEGER,          /* Bytes of payload on this page */"      \
  "  unused     INTEGER,          /* Bytes of unused space on this page */" \
  "  mx_payload INTEGER,          /* Largest payload size of all cells */"  \

  "  pgoffset   INTEGER,          /* Offset of page in file */"             \


  "  pgsize     INTEGER           /* Size of the page */"                   \





  ");"



typedef struct StatTable StatTable;
typedef struct StatCursor StatCursor;
typedef struct StatPage StatPage;
typedef struct StatCell StatCell;

  char *zPath;                    /* Value of 'path' column */
  u32 iPageno;                    /* Value of 'pageno' column */
  char *zPagetype;                /* Value of 'pagetype' column */
  int nCell;                      /* Value of 'ncell' column */
  int nPayload;                   /* Value of 'payload' column */
  int nUnused;                    /* Value of 'unused' column */
  int nMxPayload;                 /* Value of 'mx_payload' column */
  i64 iOffset;                    /* Value of 'pgOffset' column */
  int szPage;                     /* Value of 'pgSize' column */
};

struct StatTable {
  sqlite3_vtab base;
  sqlite3 *db;
};

}

static int statDecodePage(Btree *pBt, StatPage *p){
  int nUnused;
  int iOff;
  int nHdr;
  int isLeaf;
  int szPage;

  u8 *aData = sqlite3PagerGetData(p->pPg);
  u8 *aHdr = &aData[p->iPgno==1 ? 100 : 0];

  p->flags = aHdr[0];
  p->nCell = get2byte(&aHdr[3]);
  p->nMxPayload = 0;

  isLeaf = (p->flags==0x0A || p->flags==0x0D);
  nHdr = 12 - isLeaf*4 + (p->iPgno==1)*100;

  nUnused = get2byte(&aHdr[5]) - nHdr - 2*p->nCell;
  nUnused += (int)aHdr[7];
  iOff = get2byte(&aHdr[1]);
  while( iOff ){
    nUnused += get2byte(&aData[iOff+2]);
    iOff = get2byte(&aData[iOff]);
  }
  p->nUnused = nUnused;
  p->iRightChildPg = isLeaf ? 0 : sqlite3Get4byte(&aHdr[8]);
  szPage = sqlite3BtreeGetPageSize(pBt);

  if( p->nCell ){
    int i;                        /* Used to iterate through cells */
    int nUsable = szPage - sqlite3BtreeGetReserve(pBt);

    p->aCell = sqlite3_malloc((p->nCell+1) * sizeof(StatCell));
    memset(p->aCell, 0, (p->nCell+1) * sizeof(StatCell));

    for(i=0; i<p->nCell; i++){
      StatCell *pCell = &p->aCell[i];

  /* Populate the StatCursor fields with the values to be returned
  ** by the xColumn() and xRowid() methods.
  */
  if( rc==SQLITE_OK ){
    int i;
    sqlite3_file *fd;
    sqlite3_int64 x[2];
    StatPage *p = &pCsr->aPage[pCsr->iPage];
    pCsr->zName = (char *)sqlite3_column_text(pCsr->pStmt, 0);
    pCsr->iPageno = p->iPgno;

    statDecodePage(pBt, p);

    /* The default page size and offset */
    pCsr->szPage = sqlite3BtreeGetPageSize(pBt);
    pCsr->iOffset = pCsr->szPage * (p->iPgno - 1);

    /* If connected to a ZIPVFS backend, override the page size and
    ** offset with actual values obtained from ZIPVFS.
    */
    fd = sqlite3PagerFile(pPager);
    x[0] = p->iPgno;
    if( sqlite3OsFileControl(fd, 230440, &x)==SQLITE_OK ){
      pCsr->iOffset = x[0];
      pCsr->szPage = x[1];
    }

    switch( p->flags ){
      case 0x05:             /* table internal */
      case 0x02:             /* index internal */
        pCsr->zPagetype = "internal";
        break;
      case 0x0D:             /* table leaf */

      break;
    case 6:            /* unused */
      sqlite3_result_int(ctx, pCsr->nUnused);
      break;
    case 7:            /* mx_payload */
      sqlite3_result_int(ctx, pCsr->nMxPayload);
      break;
    case 8:            /* pgoffset */
      sqlite3_result_int64(ctx, pCsr->iOffset);
      break;
    case 9:            /* pgsize */
      sqlite3_result_int(ctx, pCsr->szPage);
      break;
  }
  return SQLITE_OK;
}

static int statRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
  StatCursor *pCsr = (StatCursor *)pCursor;
  *pRowid = pCsr->iPageno;

}

int SqlitetestStat_Init(Tcl_Interp *interp){
  Tcl_CreateObjCommand(interp, "register_dbstat_vtab", test_dbstat, 0, 0);
  return TCL_OK;
}
#endif /* if defined(SQLITE_TEST) || TCLSH==2 */

  SELECT * FROM stat;
} {}

ifcapable wal {
  do_execsql_test stat-0.1 {
    PRAGMA journal_mode = WAL;
    PRAGMA journal_mode = delete;
    SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
      FROM stat;
  } {wal delete sqlite_master / 1 leaf 0 0 916 0}
}

do_test stat-1.0 {
  execsql {
    CREATE TABLE t1(a, b);
    CREATE INDEX i1 ON t1(b);
    INSERT INTO t1(rowid, a, b) VALUES(2, 2, 3);
    INSERT INTO t1(rowid, a, b) VALUES(3, 4, 5);
  }
} {}
do_test stat-1.1 {
  execsql {
    SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
      FROM stat WHERE name = 't1';
  }
} {t1 / 2 leaf 2 10 998 5}
do_test stat-1.2 {
  execsql {
    SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
      FROM stat WHERE name = 'i1';
  }
} {i1 / 3 leaf 2 10 1000 5}
do_test stat-1.3 {
  execsql {
    SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
      FROM stat WHERE name = 'sqlite_master';
  }
} {sqlite_master / 1 leaf 2 77 831 40}
do_test stat-1.4 {
  execsql {
    DROP TABLE t1;
  }
} {}

do_execsql_test stat-2.1 {
  CREATE TABLE t3(a PRIMARY KEY, b);
  INSERT INTO t3(rowid, a, b) VALUES(2, a_string(111), a_string(222));
  INSERT INTO t3 SELECT a_string(110+rowid), a_string(221+rowid) FROM t3;
  INSERT INTO t3 SELECT a_string(110+rowid), a_string(221+rowid) FROM t3;
  INSERT INTO t3 SELECT a_string(110+rowid), a_string(221+rowid) FROM t3;
  INSERT INTO t3 SELECT a_string(110+rowid), a_string(221+rowid) FROM t3;
  INSERT INTO t3 SELECT a_string(110+rowid), a_string(221+rowid) FROM t3;
  SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
    FROM stat WHERE name != 'sqlite_master';
} [list \
  sqlite_autoindex_t3_1 / 3 internal 3 368 623 125       \
  sqlite_autoindex_t3_1 /000/ 8 leaf 8 946 46 123        \
  sqlite_autoindex_t3_1 /001/ 9 leaf 8 988 2 131         \
  sqlite_autoindex_t3_1 /002/ 15 leaf 7 857 137 132      \
  sqlite_autoindex_t3_1 /003/ 20 leaf 6 739 257 129      \
  t3 / 2 internal 15 0 907 0                             \

]
do_execsql_test stat-2.2 { DROP TABLE t3 } {}

do_execsql_test stat-3.1 {
  CREATE TABLE t4(x);
  CREATE INDEX i4 ON t4(x);
  INSERT INTO t4(rowid, x) VALUES(2, a_string(7777));
  SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
    FROM stat WHERE name != 'sqlite_master';
} [list \
  i4 / 3 leaf 1 103 905 7782                 \
  i4 /000+000000 9 overflow 0 1020 0 0       \
  i4 /000+000001 10 overflow 0 1020 0 0      \
  i4 /000+000002 11 overflow 0 1020 0 0      \
  i4 /000+000003 12 overflow 0 1020 0 0      \
  i4 /000+000004 13 overflow 0 1020 0 0      \

  t4 /000+000005 18 overflow 0 1020 0 0      \
  t4 /000+000006 17 overflow 0 1020 0 0      \
]

do_execsql_test stat-4.1 {
  CREATE TABLE t5(x);
  CREATE INDEX i5 ON t5(x);
  SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
    FROM stat WHERE name = 't5' OR name = 'i5';
} [list  \
  i5 / 5 leaf 0 0 1016 0 \
  t5 / 4 leaf 0 0 1016 0 \
]

db close
forcedelete test.db
sqlite3 db test.db
register_dbstat_vtab db
breakpoint
do_execsql_test stat-5.1 {
  PRAGMA auto_vacuum = OFF;
  CREATE VIRTUAL TABLE temp.stat USING dbstat;
  CREATE TABLE t1(x);
  INSERT INTO t1 VALUES(zeroblob(1513));
  INSERT INTO t1 VALUES(zeroblob(1514));
  SELECT name, path, pageno, pagetype, ncell, payload, unused, mx_payload
    FROM stat WHERE name = 't1';
} [list \
  t1 / 2 leaf 2 993 5 1517                \
  t1 /000+000000 3 overflow 0 1020 0 0    \
  t1 /001+000000 4 overflow 0 1020 0 0    \
]

finish_test

   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
   gap_cnt int,      -- Number of gaps in the page layout
   compressed_size int  -- Total bytes stored on disk
);}
mem eval $tabledef

# 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

      sum(path LIKE '%+000000') AS ovfl_cnt,
      max(mx_payload) AS mx_payload,
      sum(isinternal(pagetype, $is_index)) AS int_pages,
      sum(isleaf(pagetype, $is_index)) AS leaf_pages,
      sum(isoverflow(pagetype, $is_index)) AS ovfl_pages,
      sum(isinternal(pagetype, $is_index) * unused) AS int_unused,
      sum(isleaf(pagetype, $is_index) * unused) AS leaf_unused,
      sum(isoverflow(pagetype, $is_index) * unused) AS ovfl_unused,
      sum(pgsize) AS compressed_size
    FROM temp.dbstat WHERE name = $name
  } break

  # Column 'gap_cnt' is set to the number of non-contiguous entries in the
  # list of pages visited if the b-tree structure is traversed in a top-down
  # fashion (each node visited before its child-tree is passed). Any overflow
  # chains present are traversed from start to finish before any child-tree

      $mx_payload,
      $int_pages,
      $leaf_pages,  
      $ovfl_pages, 
      $int_unused, 
      $leaf_unused,
      $ovfl_unused,
      $gap_cnt,
      $compressed_size
    );
  }
}

proc integerify {real} {
  if {[string is double -strict $real]} {
    return [expr {wide($real)}]

      int(sum(ovfl_cnt)) as ovfl_cnt,
      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 ""
  set len [string length $title]
  set stars [string repeat * [expr 65-$len]]

  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!=$storage} {
    set pct [expr {$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} $avg_fanout
  }
  if {$total_pages>1} {