2 * $Header: /cvsroot/pgsql/contrib/pgstattuple/pgstattuple.c,v 1.2 2001/10/25 05:49:20 momjian Exp $
4 * Copyright (c) 2001 Tatsuo Ishii
6 * Permission to use, copy, modify, and distribute this software and
7 * its documentation for any purpose, without fee, and without a
8 * written agreement is hereby granted, provided that the above
9 * copyright notice and this paragraph and the following two
10 * paragraphs appear in all copies.
12 * IN NO EVENT SHALL THE AUTHOR BE LIABLE TO ANY PARTY FOR DIRECT,
13 * INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
14 * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
15 * DOCUMENTATION, EVEN IF THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED
16 * OF THE POSSIBILITY OF SUCH DAMAGE.
18 * THE AUTHOR SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS ON AN "AS
21 * IS" BASIS, AND THE AUTHOR HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE,
22 * SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
27 #include "access/heapam.h"
28 #include "access/transam.h"
30 PG_FUNCTION_INFO_V1(pgstattuple);
32 extern Datum pgstattuple(PG_FUNCTION_ARGS);
36 * returns the percentage of dead tuples
38 * C FUNCTION definition
39 * pgstattuple(NAME) returns FLOAT8
43 pgstattuple(PG_FUNCTION_ARGS)
45 Name p = PG_GETARG_NAME(0);
51 BlockNumber block = InvalidBlockNumber;
54 uint64 dead_tuple_len = 0;
55 uint32 tuple_count = 0;
56 uint32 dead_tuple_count = 0;
58 double dead_tuple_percent;
60 Buffer buffer = InvalidBuffer;
61 uint64 free_space = 0; /* free/reusable space in bytes */
62 double free_percent; /* free/reusable space in % */
64 rel = heap_openr(NameStr(*p), NoLock);
65 nblocks = RelationGetNumberOfBlocks(rel);
66 scan = heap_beginscan(rel, false, SnapshotAny, 0, NULL);
68 while ((tuple = heap_getnext(scan, 0)))
70 if (HeapTupleSatisfiesNow(tuple->t_data))
72 tuple_len += tuple->t_len;
77 dead_tuple_len += tuple->t_len;
81 if (!BlockNumberIsValid(block) ||
82 block != BlockIdGetBlockNumber(&tuple->t_self.ip_blkid))
84 block = BlockIdGetBlockNumber(&tuple->t_self.ip_blkid);
85 buffer = ReadBuffer(rel, block);
86 free_space += PageGetFreeSpace((Page) BufferGetPage(buffer));
87 ReleaseBuffer(buffer);
91 heap_close(rel, NoLock);
93 table_len = (double) nblocks *BLCKSZ;
98 dead_tuple_percent = 0.0;
103 tuple_percent = (double) tuple_len *100.0 / table_len;
104 dead_tuple_percent = (double) dead_tuple_len *100.0 / table_len;
105 free_percent = (double) free_space *100.0 / table_len;
108 elog(NOTICE, "physical length: %.2fMB live tuples: %u (%.2fMB, %.2f%%) dead tuples: %u (%.2fMB, %.2f%%) free/reusable space: %.2fMB (%.2f%%) overhead: %.2f%%",
110 table_len / 1024 / 1024, /* phsical length in MB */
112 tuple_count, /* number of live tuples */
113 (double) tuple_len / 1024 / 1024, /* live tuples in MB */
114 tuple_percent, /* live tuples in % */
116 dead_tuple_count, /* number of dead tuples */
117 (double) dead_tuple_len / 1024 / 1024, /* dead tuples in MB */
118 dead_tuple_percent, /* dead tuples in % */
120 (double) free_space / 1024 / 1024, /* free/available space in
123 free_percent, /* free/available space in % */
126 (nblocks == 0) ? 0.0 : 100.0
131 PG_RETURN_FLOAT8(dead_tuple_percent);