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statistics_format.h
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1/*-------------------------------------------------------------------------
2 *
3 * statistics_format.h
4 * Data related to the format of extended statistics, usable by both
5 * frontend and backend code.
6 *
7 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
9 *
10 * IDENTIFICATION
11 * src/include/statistics/statistics_format.h
12 *
13 *-------------------------------------------------------------------------
14 */
15#ifndef STATISTICS_FORMAT_H
16#define STATISTICS_FORMAT_H
17
18/* ----------
19 * pg_ndistinct in human-readable format is a JSON array made of elements with
20 * a predefined set of keys, like:
21 *
22 * [{"ndistinct": 11, "attributes": [3,4]},
23 * {"ndistinct": 11, "attributes": [3,6]},
24 * {"ndistinct": 11, "attributes": [4,6]},
25 * {"ndistinct": 11, "attributes": [3,4,6]},
26 * ... ]
27 * ----------
28 */
29#define PG_NDISTINCT_KEY_ATTRIBUTES "attributes"
30#define PG_NDISTINCT_KEY_NDISTINCT "ndistinct"
31
32
33/* ----------
34 * pg_dependencies in human-readable format is a JSON array made of elements
35 * with a predefined set of keys, like:
36 *
37 * [{"degree": 1.000000, "attributes": [3], "dependency": 4},
38 * {"degree": 1.000000, "attributes": [3], "dependency": 6},
39 * ... ]
40 * ----------
41 */
42
43#define PG_DEPENDENCIES_KEY_ATTRIBUTES "attributes"
44#define PG_DEPENDENCIES_KEY_DEPENDENCY "dependency"
45#define PG_DEPENDENCIES_KEY_DEGREE "degree"
46
47#endif /* STATISTICS_FORMAT_H */