1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
|
--
-- Copyright 2024 The Android Open Source Project
--
-- Licensed under the Apache License, Version 2.0 (the "License");
-- you may not use this file except in compliance with the License.
-- You may obtain a copy of the License at
--
-- https://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS,
-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-- See the License for the specific language governing permissions and
-- limitations under the License.
-- Partitions a tree into a forest of trees based on a given grouping key
-- in a structure-preserving way.
--
-- Specifically, for each tree in the output forest, all the nodes in that tree
-- have the same ancestors and descendants as in the original tree *iff* that
-- ancestor/descendent belonged to the same group.
--
-- Example:
-- Input
-- id | parent_id | group_key
-- ---+-----------+--------
-- 1 | NULL | 1
-- 2 | 1 | 1
-- 3 | 2 | 2
-- 4 | 2 | 2
-- 5 | 4 | 1
-- 6 | 4 | 3
-- 7 | 4 | 2
--
-- Or as a graph:
-- 1 (1)
-- /
-- 2 (1)
-- / \
-- 3 (2) 4 (2)
-- \
-- 5 (1)
-- / \
-- 6 (3) 7 (2)
--
-- Possible output (order of rows is implementation-defined)
-- id | parent_id | group_key
-- ---+-----------+-------
-- 1 | NULL | 1
-- 2 | 1 | 1
-- 3 | NULL | 2
-- 4 | NULL | 2
-- 5 | 2 | 1
-- 6 | NULL | 3
-- 7 | 4 | 2
--
-- Or as a forest:
-- 1 (1) 3 (2) 4 (2) 6 (3)
-- | |
-- 2 (1) 7 (2)
-- |
-- 5 (1)
CREATE PERFETTO MACRO tree_structural_partition_by_group(
-- A table/view/subquery corresponding to a tree which should be partitioned.
-- This table must have the columns "id", "parent_id" and "group_key".
--
-- Note: the columns must contain uint32 similar to ids in trace processor
-- tables (i.e. the values should be relatively dense and close to zero). The
-- implementation makes assumptions on this for performance reasons and, if
-- this criteria is not, can lead to enormous amounts of memory being
-- allocated.
tree_table TableOrSubquery
)
-- The returned table has the schema
-- (id UINT32, parent_id UINT32, group_key UINT32).
RETURNS TableOrSubquery AS
(
-- Rename the generic columns of __intrinsic_table_ptr to the actual columns.
SELECT c0 AS id, c1 AS parent_id, c2 AS group_key
FROM __intrinsic_table_ptr((
-- Aggregate function to perform the partitioning algorithm.
SELECT __intrinsic_structural_tree_partition(g.id, g.parent_id, g.group_key)
FROM $tree_table g
))
-- Bind the dynamic columns in the |__intrinsic_table_ptr| to the columns of
-- the partitioning table.
WHERE __intrinsic_table_ptr_bind(c0, 'node_id')
AND __intrinsic_table_ptr_bind(c1, 'parent_node_id')
AND __intrinsic_table_ptr_bind(c2, 'group_key')
);
|
