404-solution / includes / stats / StatusCountsMutationSync.php

StatusCountsMutationSync.php in 404 Solution trunk, at includes/stats/StatusCountsMutationSync.php

130 lines 5.2 KB

Raw Download Zip

1	<?php
2
3	if (!defined('ABSPATH')) {
4	exit;
5	}
6
7	/**
8	* Keeps the cached admin status counts consistent with a redirect mutation.
9	*
10	* Foreground count reads are cache-only: the SUM(CASE) aggregate behind the
11	* tab badges is a full scan of the redirects table, so it was moved to cron.
12	* That left every mutation's own effect invisible to the user who caused it --
13	* trash a captured 404 and the Trash badge kept its old number until a
14	* background recompute landed, which on a host with a cron backlog is minutes.
15	*
16	* The fix is not to re-run the aggregate but to apply the delta the mutation
17	* caused. A mutation is bracketed by two reads of the affected rows'
18	* (status, disabled) distribution; the difference is the exact delta, so
19	* inserts, status changes, trash, restore and deletes all work through the
20	* same path without this class needing to know which one happened. The reads
21	* are scoped to the rows the mutation already touches, never table-wide.
22	*
23	* Any residual drift is corrected by the next full recompute, so a failed
24	* read degrades to the previous invalidate-only behavior rather than to a
25	* wrong number.
26	*/
27	class ABJ_404_Solution_StatusCountsMutationSync {
28
29	/** @var ABJ_404_Solution_DatabaseQueryInterface */
30	private $dbCore;
31
32	/** @param ABJ_404_Solution_DatabaseQueryInterface $dbCore */
33	public function __construct($dbCore) {
34	$this->dbCore = $dbCore;
35	}
36
37	/**
38	* The (status, disabled) distribution of the rows a condition selects.
39	* Take this immediately before a mutation and hand it to syncSince().
40	*
41	* @param string $whereClause SQL WHERE body. Plugin-controlled text only:
42	* every caller-supplied value must travel in $params.
43	* @param array<int, mixed> $params Bound parameters for $whereClause.
44	* @return array<int, array{status:int,disabled:int,count:int}>\|null Null when the
45	* read failed, which makes the paired sync a no-op.
46	*/
47	public function snapshot(string $whereClause, array $params = array()): ?array {
48	$redirectsTable = $this->dbCore->doTableNameReplacements("{wp_abj404_redirects}");
49	$query = "SELECT status, disabled, COUNT(*) as row_count FROM `" . $redirectsTable . "`"
50	. " WHERE " . $whereClause . " GROUP BY status, disabled";
51	$options = array();
52	if ($params !== array()) {
53	$options['query_params'] = $params;
54	}
55	$result = $this->dbCore->queryAndGetResults($query, $options);
56	if (!empty($result['last_error']) \|\| !empty($result['timed_out'])) {
57	return null;
58	}
59
60	$histogram = array();
61	$rows = isset($result['rows']) && is_array($result['rows']) ? $result['rows'] : array();
62	foreach ($rows as $row) {
63	if (!is_array($row)) {
64	continue;
65	}
66	$histogram[] = array(
67	'status' => isset($row['status']) && is_scalar($row['status']) ? (int)$row['status'] : -1,
68	'disabled' => isset($row['disabled']) && is_scalar($row['disabled']) ? (int)$row['disabled'] : -1,
69	'count' => isset($row['row_count']) && is_scalar($row['row_count']) ? (int)$row['row_count'] : 0,
70	);
71	}
72	return $histogram;
73	}
74
75	/**
76	* Apply the delta between a snapshot and the current state of the same
77	* rows. A no-op when either read failed, so a mutation never publishes a
78	* count it could not derive.
79	*
80	* @param array<int, array{status:int,disabled:int,count:int}>\|null $before From snapshot().
81	* @param string $whereClause Same condition the snapshot used.
82	* @param array<int, mixed> $params Same parameters the snapshot used.
83	* @return void
84	*/
85	public function syncSince(?array $before, string $whereClause, array $params = array()): void {
86	if ($before === null) {
87	return;
88	}
89	$after = $this->snapshot($whereClause, $params);
90	if ($after === null) {
91	return;
92	}
93	ABJ_404_Solution_StatusCountsRepository::applyDelta(
94	ABJ_404_Solution_StatusCountBuckets::delta($before, $after)
95	);
96	}
97
98	/**
99	* Apply the delta for rows that are simply gone, for a mutation whose
100	* after-state needs no second read (an unconditional DELETE of exactly
101	* the snapshotted set).
102	*
103	* @param array<int, array{status:int,disabled:int,count:int}>\|null $removed From snapshot().
104	* @return void
105	*/
106	public function syncRemoved(?array $removed): void {
107	if ($removed === null \|\| $removed === array()) {
108	return;
109	}
110	ABJ_404_Solution_StatusCountsRepository::applyDelta(
111	ABJ_404_Solution_StatusCountBuckets::delta($removed, array())
112	);
113	}
114
115	/**
116	* Apply the delta for one freshly inserted row. An insert needs no reads
117	* at all: the row that just landed is the whole delta, which matters on
118	* the frontend capture hot path where an extra query per 404 is not free.
119	*
120	* @param int $status
121	* @param int $disabled
122	* @return void
123	*/
124	public function syncInserted(int $status, int $disabled): void {
125	ABJ_404_Solution_StatusCountsRepository::applyDelta(
126	ABJ_404_Solution_StatusCountBuckets::deltaForRows($status, $disabled, 1, 1)
127	);
128	}
129	}
130