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<?php |
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|
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if (!defined('ABSPATH')) { |
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exit; |
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} |
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|
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/** |
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* Engine-aware per-query timeout helpers. |
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* |
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* Centralizes the SQL-level timeout mechanism so every query routed through |
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* queryAndGetResults() inherits a fail-fast deadline before the host's silent |
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* connection-drop kicks in: |
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* |
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* - MySQL 5.7.8+ pure SELECT: MAX_EXECUTION_TIME(ms) optimizer hint. |
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* - MySQL non-SELECT: no SQL-level mechanism (left unchanged). |
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* - MariaDB 10.1+ any DML/DDL: SET STATEMENT max_statement_time=N FOR ... |
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* |
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* Also provides query-shape probes used by the routing layer in |
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* queryAndGetResults() to decide between $wpdb->get_results() vs |
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* $wpdb->query() based on whether a wrapped query produces rows. |
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* |
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* Composed into ABJ_404_Solution_DataAccess. No state of its own; uses the |
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* global $wpdb to detect engine version. Pure functions otherwise. |
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*/ |
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class ABJ_404_Solution_DatabaseQueryTimeoutManager { |
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|
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/** @var ABJ_404_Solution_DatabaseCore */ |
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private $core; |
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|
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/** @var ABJ_404_Solution_Logging */ |
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private $logger; |
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|
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/** |
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* @param ABJ_404_Solution_DatabaseCore $core |
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* @param ABJ_404_Solution_Logging $logger |
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*/ |
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public function __construct(ABJ_404_Solution_DatabaseCore $core, $logger) { |
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$this->core = $core; |
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$this->logger = $logger; |
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} |
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|
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/** |
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* Forward DatabaseCore infrastructure calls that remain owned by the core. |
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* |
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* @param string $name |
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* @param array<int, mixed> $arguments |
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* @return mixed |
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*/ |
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public function __call(string $name, array $arguments) { |
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return $this->core->$name(...$arguments); |
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} |
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|
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/** |
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* @param string $query |
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* @return bool |
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*/ |
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public function queryStartsWithSelect(string $query): bool { |
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// SQL loaded from .sql files is wrapped in leading comments. |
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// Treat "/* ... */ SELECT ..." as a SELECT query for timeout purposes. |
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return preg_match('/^\s*(?:\/\*[\s\S]*?\*\/\s*)*SELECT\s/i', $query) === 1; |
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} |
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|
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/** |
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* Returns true if the query produces a result set (rows), so it should |
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* be sent through $wpdb->get_results(). Returns false for INSERT, UPDATE, |
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* DELETE, REPLACE, DDL, SET, etc. Those should go through $wpdb->query(). |
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* |
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* Sees past leading SQL comments and any `SET STATEMENT max_statement_time=N FOR ` |
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* timeout wrapper. The wrapper is critical because applyQueryTimeout() prepends |
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* it on MariaDB, which would otherwise mask the underlying statement type. |
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* |
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* Misclassification triggered the 4.1.7 spell-check `mysqli_num_fields(true)` |
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* TypeError on PHP 8.1+ MariaDB sites. See DataAccessNonSelectRoutingTest. |
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* |
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* @param string $query |
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* @return bool |
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*/ |
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public function queryProducesResultRows(string $query): bool { |
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$stripped = (string)preg_replace('/^\s*(?:\/\*[\s\S]*?\*\/\s*)+/', '', $query); |
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$stripped = (string)preg_replace( |
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'/^\s*SET\s+STATEMENT\s+\w+\s*=\s*\d+\s+FOR\s+/i', |
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'', |
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$stripped, |
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1 |
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); |
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// Strip nested leading comments inside the SET STATEMENT wrapper too. |
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$stripped = (string)preg_replace('/^\s*(?:\/\*[\s\S]*?\*\/\s*)+/', '', $stripped); |
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return preg_match('/^\s*(SELECT|SHOW|EXPLAIN|DESCRIBE|DESC)\s/i', $stripped) === 1; |
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} |
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|
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/** |
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* Apply a DB-level timeout to any query type. |
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* |
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* Dispatches to the appropriate engine-specific mechanism: |
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* - Pure SELECT: MySQL optimizer hint or MariaDB SET STATEMENT |
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* - INSERT...SELECT (or any non-leading SELECT): MariaDB SET STATEMENT |
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* or MySQL hint injected into the embedded SELECT |
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* - Other DML/DDL: MariaDB SET STATEMENT (MySQL has no mechanism for |
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* non-SELECT timeouts; these queries are typically fast) |
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* |
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* Skips queries that already carry a timeout hint to prevent double-wrapping |
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* (e.g. callers that used to apply timeouts manually before this was centralized). |
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* |
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* @param string $query Any SQL query |
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* @param int $timeoutSeconds Maximum execution time in seconds |
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* @return string The query with timeout applied (or unchanged if no mechanism) |
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*/ |
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public function applyQueryTimeout( |
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string $query, |
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int $timeoutSeconds, |
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?ABJ_404_Solution_DatabaseQueryPreflightTracer $preflight = null |
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): string { |
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// Skip if a timeout hint is already present (prevents double-wrapping). |
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if (preg_match('/MAX_EXECUTION_TIME|max_statement_time/i', $query)) { |
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return $query; |
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} |
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|
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if ($this->queryStartsWithSelect($query)) { |
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return $this->applySelectTimeout($query, $timeoutSeconds, $preflight); |
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} |
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if (preg_match('/SELECT\s/i', $query)) { |
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// INSERT...SELECT, CREATE TABLE...SELECT, etc. |
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return $this->applyNonLeadingSelectTimeout($query, $timeoutSeconds, $preflight); |
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} |
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// Plain INSERT, UPDATE, DELETE, DDL: only MariaDB has a timeout mechanism. |
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return $this->applyStatementTimeout($query, $timeoutSeconds, $preflight); |
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} |
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|
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/** |
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* Detect the DB engine. Returns true for MariaDB, false for MySQL/unknown. |
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* @return bool |
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*/ |
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public function isMariaDB( |
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?ABJ_404_Solution_DatabaseQueryPreflightTracer $preflight = null |
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): bool { |
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global $wpdb; |
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if (!isset($wpdb) || !is_object($wpdb)) { |
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return false; |
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} |
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$source = isset($wpdb->dbh) |
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&& function_exists('mysqli_get_server_info') |
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&& $wpdb->dbh instanceof \mysqli |
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? 'mysqli_server_info' |
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: 'wpdb_db_version'; |
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$detect = static function () use ($wpdb): bool { |
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if (isset($wpdb->dbh) && function_exists('mysqli_get_server_info') |
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&& $wpdb->dbh instanceof \mysqli) { |
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$dbVersion = mysqli_get_server_info($wpdb->dbh); |
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} else { |
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/** @var wpdb $wpdb */ |
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$dbVersion = $wpdb->db_version() ?? ''; |
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} |
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return stripos((string)$dbVersion, 'mariadb') !== false; |
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}; |
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try { |
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if ($preflight === null) { |
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return $detect(); |
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} |
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return $preflight->trace( |
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ABJ_404_Solution_DatabaseQueryPreflightTracer::ENGINE_DETECTION, |
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$detect, |
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array( |
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'fields' => array('engine_source' => $source), |
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'result_fields' => static fn(bool $isMariaDb): array => array( |
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'engine' => $isMariaDb ? 'mariadb' : 'mysql_or_unknown', |
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), |
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) |
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); |
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} catch (\Throwable $e) { |
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// Falling back to "not MariaDB" is safe (it only forgoes MariaDB's |
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// timeout syntax), and on a test double or an early-boot wpdb |
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// without db_version() it is also expected. But safe is not the |
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// same as uninteresting: if this starts throwing at runtime, the |
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// statement-timeout path quietly turns itself off on every query |
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// for the rest of the request, and a silent catch here is the |
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// reason nobody would ever find out. Record it and degrade. |
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$this->logger->debugMessage( |
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'DB engine detection failed; assuming not-MariaDB and skipping the MariaDB ' |
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. 'statement-timeout syntax. Source: ' . $source . '. ' |
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. get_class($e) . ' (code ' . (string)$e->getCode() . '): ' . $e->getMessage(), |
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$e |
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); |
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return false; |
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} |
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} |
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|
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/** |
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* Apply timeout to a pure SELECT query. |
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* |
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* MySQL 5.7.8+: MAX_EXECUTION_TIME(ms) optimizer hint. |
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* MariaDB 10.1+: SET STATEMENT max_statement_time=N FOR ... |
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* |
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* @param string $query A SELECT query |
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* @param int $timeoutSeconds Maximum execution time in seconds |
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* @return string The query with timeout hint applied |
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*/ |
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public function applySelectTimeout( |
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string $query, |
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int $timeoutSeconds, |
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?ABJ_404_Solution_DatabaseQueryPreflightTracer $preflight = null |
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): string { |
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if ($this->isMariaDB($preflight) |
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&& !$this->isSetStatementWrapperUnsupported($preflight)) { |
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return "SET STATEMENT max_statement_time=" . $timeoutSeconds . " FOR " . $query; |
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} |
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// MySQL hint also works for the MariaDB-with-disabled-wrapper case: |
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// MariaDB silently ignores unrecognized optimizer hints (parses as a |
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// comment), so the SELECT runs without a per-statement deadline. |
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$timeoutMs = $timeoutSeconds * 1000; |
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$timedQuery = preg_replace( |
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'/^(\s*(?:\/\*[\s\S]*?\*\/\s*)*SELECT\s)/i', |
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'$1/*+ MAX_EXECUTION_TIME(' . $timeoutMs . ') */ ', |
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$query |
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); |
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return ($timedQuery !== null) ? $timedQuery : $query; |
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} |
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|
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/** |
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* Apply timeout to a query containing a non-leading SELECT (INSERT...SELECT, etc.). |
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* |
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* MariaDB 10.1+: SET STATEMENT max_statement_time=N FOR ... (wraps entire statement). |
| 222 |
* MySQL 5.7.8+: MAX_EXECUTION_TIME(ms) hint injected into the first SELECT keyword. |
| 223 |
* |
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* @param string $query An INSERT...SELECT or similar query |
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* @param int $timeoutSeconds Maximum execution time in seconds |
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* @return string The query with timeout applied |
| 227 |
*/ |
| 228 |
public function applyNonLeadingSelectTimeout( |
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string $query, |
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int $timeoutSeconds, |
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?ABJ_404_Solution_DatabaseQueryPreflightTracer $preflight = null |
| 232 |
): string { |
| 233 |
if ($this->isMariaDB($preflight) |
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&& !$this->isSetStatementWrapperUnsupported($preflight)) { |
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return "SET STATEMENT max_statement_time=" . $timeoutSeconds . " FOR " . $query; |
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} |
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$timeoutMs = $timeoutSeconds * 1000; |
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$timedQuery = preg_replace( |
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'/(SELECT\s)/i', |
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'SELECT /*+ MAX_EXECUTION_TIME(' . $timeoutMs . ') */ ', |
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$query, |
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1 |
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); |
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return ($timedQuery !== null) ? $timedQuery : $query; |
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} |
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|
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/** |
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* Apply timeout to a non-SELECT statement (INSERT, UPDATE, DELETE, DDL). |
| 249 |
* |
| 250 |
* MariaDB 10.1+: SET STATEMENT max_statement_time=N FOR ... works on all DML. |
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* MySQL: has no SQL-level timeout mechanism for non-SELECT queries. |
| 252 |
* |
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* @param string $query Any non-SELECT query |
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* @param int $timeoutSeconds Maximum execution time in seconds |
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* @return string The query with timeout applied (unchanged on MySQL) |
| 256 |
*/ |
| 257 |
public function applyStatementTimeout( |
| 258 |
string $query, |
| 259 |
int $timeoutSeconds, |
| 260 |
?ABJ_404_Solution_DatabaseQueryPreflightTracer $preflight = null |
| 261 |
): string { |
| 262 |
if ($this->isMariaDB($preflight) |
| 263 |
&& !$this->isSetStatementWrapperUnsupported($preflight)) { |
| 264 |
return "SET STATEMENT max_statement_time=" . $timeoutSeconds . " FOR " . $query; |
| 265 |
} |
| 266 |
// MySQL has no timeout mechanism for non-SELECT queries. MariaDB hosts |
| 267 |
// that have rejected SET STATEMENT (privilege denied or syntax not |
| 268 |
// understood) earlier in this request fall through here too: the |
| 269 |
// staged build's per-tick budget enforcement degrades to the cron |
| 270 |
// tick's own wall-clock deadline rather than per-statement. |
| 271 |
return $query; |
| 272 |
} |
| 273 |
|
| 274 |
/** |
| 275 |
* Read the request-local/persisted wrapper capability under its own |
| 276 |
* preflight boundary. The result descriptor exposes only hit/miss state. |
| 277 |
*/ |
| 278 |
private function isSetStatementWrapperUnsupported( |
| 279 |
?ABJ_404_Solution_DatabaseQueryPreflightTracer $preflight |
| 280 |
): bool { |
| 281 |
if ($preflight === null) { |
| 282 |
return ABJ_404_Solution_DatabaseRuntimeState::isSetStatementWrapperUnsupported(); |
| 283 |
} |
| 284 |
$source = ABJ_404_Solution_DatabaseRuntimeState::setStatementWrapperCapabilitySource(); |
| 285 |
return $preflight->trace( |
| 286 |
ABJ_404_Solution_DatabaseQueryPreflightTracer::TIMEOUT_CAPABILITY_CACHE, |
| 287 |
static fn(): bool => |
| 288 |
ABJ_404_Solution_DatabaseRuntimeState::isSetStatementWrapperUnsupported(), |
| 289 |
array( |
| 290 |
'fields' => array('cache_source' => $source), |
| 291 |
'result_fields' => static function (bool $unsupported) use ($source): array { |
| 292 |
if ($source === 'transient') { |
| 293 |
return array( |
| 294 |
'cache_outcome' => $unsupported |
| 295 |
? 'hit_unsupported' |
| 296 |
: 'miss_supported', |
| 297 |
); |
| 298 |
} |
| 299 |
return array( |
| 300 |
'cache_outcome' => $unsupported |
| 301 |
? 'request_local_unsupported' |
| 302 |
: 'request_local_supported', |
| 303 |
); |
| 304 |
}, |
| 305 |
) |
| 306 |
); |
| 307 |
} |
| 308 |
|
| 309 |
/** |
| 310 |
* True when $query begins with the timeout wrapper this trait emits: |
| 311 |
* `SET STATEMENT max_statement_time=N FOR ...`. Used by the wrapper |
| 312 |
* fallback path to confirm the failed query was wrapped before stripping. |
| 313 |
* |
| 314 |
* @param string $query |
| 315 |
* @return bool |
| 316 |
*/ |
| 317 |
public function queryHasSetStatementWrapper(string $query): bool { |
| 318 |
return preg_match( |
| 319 |
'/^\s*SET\s+STATEMENT\s+max_statement_time\s*=\s*\d+\s+FOR\s+/i', |
| 320 |
$query |
| 321 |
) === 1; |
| 322 |
} |
| 323 |
|
| 324 |
/** |
| 325 |
* Strip the leading `SET STATEMENT max_statement_time=N FOR ` wrapper. |
| 326 |
* Returns the unwrapped statement, or the input unchanged if no wrapper |
| 327 |
* is present. |
| 328 |
* |
| 329 |
* @param string $query |
| 330 |
* @return string |
| 331 |
*/ |
| 332 |
public function stripSetStatementWrapper(string $query): string { |
| 333 |
$stripped = preg_replace( |
| 334 |
'/^\s*SET\s+STATEMENT\s+max_statement_time\s*=\s*\d+\s+FOR\s+/i', |
| 335 |
'', |
| 336 |
$query, |
| 337 |
1 |
| 338 |
); |
| 339 |
return is_string($stripped) ? $stripped : $query; |
| 340 |
} |
| 341 |
|
| 342 |
/** |
| 343 |
* Re-execute a query without the `SET STATEMENT max_statement_time=N FOR ` |
| 344 |
* wrapper after the server rejected the wrapper itself (privilege denied |
| 345 |
* or syntax not understood). Caches the result in request-local state and |
| 346 |
* a short-lived WordPress transient so subsequent queries and fresh PHP |
| 347 |
* requests skip the known-unsupported wrapper until the capability is |
| 348 |
* probed again. |
| 349 |
* |
| 350 |
* Result harvest mirrors retrying recovery paths such as |
| 351 |
* attemptMissingTableRepairAndRetry(): |
| 352 |
* write into $result by reference so the caller's downstream branches see |
| 353 |
* the retry's outcome instead of the original error. |
| 354 |
* |
| 355 |
* $query is also passed by reference and mutated to the unwrapped form |
| 356 |
* on success. Downstream retry paths in queryAndGetResults() (transient |
| 357 |
* reconnect, deadlock retry, etc.) re-execute $query, so leaving the |
| 358 |
* wrapper in place would re-trigger the same rejection on every retry. |
| 359 |
* |
| 360 |
* @param string $query Passed by reference. Mutated to the unwrapped form. |
| 361 |
* @param array<string, mixed> $result Passed by reference; updated with retry rows / error. |
| 362 |
* @param 'OBJECT'|'OBJECT_K'|'ARRAY_A'|'ARRAY_N' $resultType wpdb output type for get_results(). |
| 363 |
* @param ABJ_404_Solution_DatabaseQueryRecoveryTracer|null $tracer |
| 364 |
* @return void |
| 365 |
*/ |
| 366 |
public function retryWithoutSetStatementWrapper( |
| 367 |
string &$query, |
| 368 |
array &$result, |
| 369 |
string $resultType, |
| 370 |
?ABJ_404_Solution_DatabaseQueryRecoveryTracer $tracer = null |
| 371 |
): void { |
| 372 |
if (!$this->queryHasSetStatementWrapper($query)) { |
| 373 |
// Defensive: nothing to strip. Caller misclassified the error. |
| 374 |
return; |
| 375 |
} |
| 376 |
$unwrapped = $this->stripSetStatementWrapper($query); |
| 377 |
// Cache the negative result locally and across requests so the host |
| 378 |
// does not repeatedly pay for the same known-failing capability probe. |
| 379 |
ABJ_404_Solution_DatabaseRuntimeState::setSetStatementWrapperUnsupported(true); |
| 380 |
if (class_exists('ABJ_404_Solution_AjaxStageDiagnostics')) { |
| 381 |
ABJ_404_Solution_AjaxStageDiagnostics::addStageMetadata(array( |
| 382 |
'db_timeout_mode' => 'unwrapped', |
| 383 |
)); |
| 384 |
} |
| 385 |
$this->logger->warn( |
| 386 |
'SET STATEMENT timeout wrapper rejected by server; ' |
| 387 |
. 'retrying query without a DB-level timeout and caching the ' |
| 388 |
. 'unsupported capability for one hour.' |
| 389 |
); |
| 390 |
|
| 391 |
global $wpdb; |
| 392 |
/** @var wpdb $wpdb */ |
| 393 |
$retryError = isset($result['last_error']) && is_scalar($result['last_error']) |
| 394 |
? (string)$result['last_error'] |
| 395 |
: ''; |
| 396 |
if ($tracer === null) { |
| 397 |
if (!$this->core->connectionManager()->resetForRetry($retryError)) { |
| 398 |
return; |
| 399 |
} |
| 400 |
} else { |
| 401 |
$reset = $tracer->traceOperation( |
| 402 |
'timeout_wrapper', |
| 403 |
'connection_retry_reset', |
| 404 |
fn(): bool => $this->core->connectionManager()->resetForRetry($retryError) |
| 405 |
); |
| 406 |
if (!$reset) { |
| 407 |
return; |
| 408 |
} |
| 409 |
} |
| 410 |
// Mutate $query so downstream retry paths execute the unwrapped form. |
| 411 |
$query = $unwrapped; |
| 412 |
// Re-route classification past any leading comments and the (now-absent) |
| 413 |
// wrapper. Using queryProducesResultRows on the unwrapped query keeps |
| 414 |
// the routing correct for INSERT/UPDATE/DELETE/DDL. |
| 415 |
// SET STATEMENT wrapper-rejection recovery is a DAO-internal primitive |
| 416 |
// (parallel to attemptMissingTableRepairAndRetry). It must call |
| 417 |
// $wpdb directly: re-routing through queryAndGetResults() would |
| 418 |
// re-enter the same SET STATEMENT detection path, deepening the call |
| 419 |
// stack on every retry. Per-bypass approval markers are inline below. |
| 420 |
$unwrappedProducesRows = $this->queryProducesResultRows($unwrapped); |
| 421 |
$retry = function () use ($wpdb, $unwrapped, $resultType, $unwrappedProducesRows): array { |
| 422 |
if ($unwrappedProducesRows) { |
| 423 |
// DAO-bypass-approved: SET STATEMENT wrapper-rejection retry primitive. |
| 424 |
$retried = array('rows' => $wpdb->get_results($unwrapped, $resultType)); |
| 425 |
} else { |
| 426 |
// DAO-bypass-approved: SET STATEMENT wrapper-rejection retry primitive. |
| 427 |
$wpdb->query($unwrapped); |
| 428 |
$retried = array('rows' => array()); |
| 429 |
} |
| 430 |
$this->core->resultHarvester()->harvestWpdbResult($retried); |
| 431 |
return $retried; |
| 432 |
}; |
| 433 |
$retried = $tracer === null |
| 434 |
? $retry() |
| 435 |
: $tracer->traceAttempt( |
| 436 |
'timeout_wrapper', |
| 437 |
'timeout_wrapper_rejected', |
| 438 |
$retry |
| 439 |
); |
| 440 |
$result = array_merge($result, $retried); |
| 441 |
} |
| 442 |
} |
| 443 |
|
