Your IP : 216.73.216.5
<?php
/**
* File: UsageStatistics_Source_DbQueriesLog.php
*
* @package W3TC
*/
namespace W3TC;
/**
* Class UsageStatistics_Source_DbQueriesLog
*
* Database queries debug log reader - provides data from this logfile
*
* phpcs:disable WordPress.PHP.NoSilencedErrors.Discouraged
* phpcs:disable WordPress.WP.AlternativeFunctions
*/
class UsageStatistics_Source_DbQueriesLog {
/**
* The timestamp representing the start time for filtering log entries.
*
* @var int
*/
private $timestamp_start;
/**
* The column by which the log entries should be sorted.
*
* @var string
*/
private $sort_column;
/**
* The associative array holding query data by query string.
*
* @var array
*/
private $by_query = array();
/**
* Flag indicating whether more log entries are needed for parsing.
*
* @var bool
*/
private $more_log_needed = true;
/**
* Constructor for initializing the object with a start timestamp and sort column.
*
* @param int $timestamp_start The timestamp representing the start time for filtering log entries.
* @param string $sort_column The column by which the log entries should be sorted.
*
* @return void
*/
public function __construct( $timestamp_start, $sort_column ) {
$this->timestamp_start = $timestamp_start;
$this->sort_column = $sort_column;
}
/**
* Retrieves and processes log entries, sorting them based on the specified column, and returns the top 200 entries.
*
* This method reads the log file from the end, processes the data, and filters based on the timestamp.
* The results are returned as an array containing various statistics such as query counts, average size, and time.
*
* @return array An array of sorted log entries containing statistics about queries such as total count, hit count,
* average size, average time, total time, and reasons.
*
* @throws \Exception If the log file cannot be opened.
*/
public function list_entries() {
$log_filename = Util_Debug::log_filename( 'dbcache-queries' );
$h = @fopen( $log_filename, 'rb' );
if ( ! $h ) {
throw new \Exception(
\esc_html(
sprintf(
// translators: 1 Log filename.
\__( 'Failed to open log file %1$s.', 'w3-total-cache' ),
$log_filename
)
)
);
}
fseek( $h, 0, SEEK_END );
$pos = ftell( $h );
$unparsed_head = '';
while ( $pos >= 0 && $this->more_log_needed ) {
$pos -= 8192;
if ( $pos <= 0 ) {
$pos = 0;
}
fseek( $h, $pos );
$s = fread( $h, 8192 );
$unparsed_head = $this->parse_string( $s . $unparsed_head, $pos > 0 );
if ( $pos <= 0 ) {
$this->more_log_needed = false;
}
}
$output = array();
foreach ( $this->by_query as $query => $data ) {
$output[] = array(
'query' => $query,
'count_total' => $data['count_total'],
'count_hit' => $data['count_hit'],
'avg_size' => (int) ( $data['sum_size'] / $data['count_total'] ),
'avg_time_ms' => (int) ( $data['sum_time_ms'] / $data['count_total'] ),
'sum_time_ms' => (int) $data['sum_time_ms'],
'reasons' => $data['reasons'],
);
}
usort(
$output,
function ( $a, $b ) {
return (int) ( $b[ $this->sort_column ] ) - (int) ( $a[ $this->sort_column ] );
}
);
$output = array_slice( $output, 0, 200 );
return $output;
}
/**
* Parses a string of log data, processing individual lines and pushing relevant information to be analyzed.
*
* This method processes a chunk of log data, handling the option to skip the first line and breaking the data into
* individual lines for further analysis.
*
* @param string $s The log data string to be parsed.
* @param bool $skip_first_line Whether to skip the first line of the string.
*
* @return string The unparsed head of the log data, if any.
*/
private function parse_string( $s, $skip_first_line ) {
$s_length = strlen( $s );
$unparsed_head = '';
$n = 0;
if ( $skip_first_line ) {
for ( ; $n < $s_length; $n++ ) {
$c = substr( $s, $n, 1 );
if ( "\r" === $c || "\n" === $c ) {
$unparsed_head = substr( $s, 0, $n + 1 );
break;
}
}
}
$line_start = $n;
for ( ; $n < $s_length; $n++ ) {
$c = substr( $s, $n, 1 );
if ( "\r" === $c || "\n" === $c ) {
if ( $n > $line_start ) {
$this->push_line( substr( $s, $line_start, $n - $line_start ) );
}
$line_start = $n + 1;
}
}
return $unparsed_head;
}
/**
* Processes a single line of log data, extracting relevant information and updating the query statistics.
*
* This method parses a line of log data, updating the query statistics for the given query (e.g., count, size, time, etc.).
* It also checks if more log data is needed based on the timestamp and ensures that data for each query is stored appropriately.
*
* @param string $line The log line to be processed.
*
* @return void
*/
private function push_line( $line ) {
$matches = str_getcsv( $line, "\t" );
if ( ! $matches ) {
return;
}
$date_string = $matches[0];
$query = $matches[2];
$time_taken_ms = isset( $matches[3] ) ? (float) $matches[3] / 1000 : 0;
$reason = isset( $matches[4] ) ? $matches[4] : '';
$hit = isset( $matches[5] ) ? $matches[5] : false;
$size = isset( $matches[6] ) ? $matches[6] : 0;
$time = strtotime( $date_string );
// dont read more if we touched entries before timeperiod of collection.
if ( $time < $this->timestamp_start ) {
$this->more_log_needed = false;
}
if ( ! isset( $this->by_query[ $query ] ) ) {
$this->by_query[ $query ] = array(
'count_total' => 0,
'count_hit' => 0,
'sum_size' => 0,
'sum_time_ms' => 0,
'reasons' => array(),
);
}
++$this->by_query[ $query ]['count_total'];
if ( $hit ) {
++$this->by_query[ $query ]['count_hit'];
}
$this->by_query[ $query ]['sum_size'] += $size;
$this->by_query[ $query ]['sum_time_ms'] += $time_taken_ms;
if ( ! in_array( $reason, $this->by_query[ $query ]['reasons'], true ) ) {
$this->by_query[ $query ]['reasons'][] = $reason;
}
}
}