<?php
/* vim: set expandtab sw=4 ts=4 sts=4: */
/**
 * functions for displaying server status variables
 *
 * @usedby  server_status_variables.php
 *
 * @package PhpMyAdmin
 */
namespace PhpMyAdmin\Server\Status;

use PhpMyAdmin\Server\Status\Data;
use PhpMyAdmin\Url;
use PhpMyAdmin\Util;

/**
 * PhpMyAdmin\Server\Status\Variables class
 *
 * @package PhpMyAdmin
 */
class Variables
{
    /**
     * Returns the html for the list filter
     *
     * @param Data $serverStatusData Server status data
     *
     * @return string
     */
    public static function getHtmlForFilter(Data $serverStatusData)
    {
        $filterAlert = '';
        if (! empty($_REQUEST['filterAlert'])) {
            $filterAlert = ' checked="checked"';
        }
        $filterText = '';
        if (! empty($_REQUEST['filterText'])) {
            $filterText = htmlspecialchars($_REQUEST['filterText']);
        }
        $dontFormat = '';
        if (! empty($_REQUEST['dontFormat'])) {
            $dontFormat = ' checked="checked"';
        }

        $retval  = '';
        $retval .= '<fieldset id="tableFilter">';
        $retval .= '<legend>' . __('Filters') . '</legend>';
        $retval .= '<form action="server_status_variables.php'
            . Url::getCommon() . '">';
        $retval .= '<input type="submit" value="' . __('Refresh') . '" />';
        $retval .= '<div class="formelement">';
        $retval .= '<label for="filterText">' . __('Containing the word:') . '</label>';
        $retval .= '<input name="filterText" type="text" id="filterText" '
            . 'value="' . $filterText . '" />';
        $retval .= '</div>';
        $retval .= '<div class="formelement">';
        $retval .= '<input' . $filterAlert . ' type="checkbox" '
            . 'name="filterAlert" id="filterAlert" />';
        $retval .= '<label for="filterAlert">';
        $retval .= __('Show only alert values');
        $retval .= '</label>';
        $retval .= '</div>';
        $retval .= '<div class="formelement">';
        $retval .= '<select id="filterCategory" name="filterCategory">';
        $retval .= '<option value="">' . __('Filter by category…') . '</option>';

        foreach ($serverStatusData->sections as $section_id => $section_name) {
            if (isset($serverStatusData->sectionUsed[$section_id])) {
                if (! empty($_REQUEST['filterCategory'])
                    && $_REQUEST['filterCategory'] == $section_id
                ) {
                    $selected = ' selected="selected"';
                } else {
                    $selected = '';
                }
                $retval .= '<option' . $selected . ' value="' . $section_id . '">';
                $retval .= htmlspecialchars($section_name) . '</option>';
            }
        }
        $retval .= '</select>';
        $retval .= '</div>';
        $retval .= '<div class="formelement">';
        $retval .= '<input' . $dontFormat . ' type="checkbox" '
            . 'name="dontFormat" id="dontFormat" />';
        $retval .= '<label for="dontFormat">';
        $retval .= __('Show unformatted values');
        $retval .= '</label>';
        $retval .= '</div>';
        $retval .= '</form>';
        $retval .= '</fieldset>';

        return $retval;
    }

    /**
     * Prints the suggestion links
     *
     * @param Data $serverStatusData Server status data
     *
     * @return string
     */
    public static function getHtmlForLinkSuggestions(Data $serverStatusData)
    {
        $retval  = '<div id="linkSuggestions" class="defaultLinks hide">';
        $retval .= '<p class="notice">' . __('Related links:');
        foreach ($serverStatusData->links as $section_name => $section_links) {
            $retval .= '<span class="status_' . $section_name . '"> ';
            $i = 0;
            foreach ($section_links as $link_name => $link_url) {
                if ($i > 0) {
                    $retval .= ', ';
                }
                if ('doc' == $link_name) {
                    $retval .= Util::showMySQLDocu($link_url);
                } else {
                    $retval .= '<a href="' . $link_url . '">' . $link_name . '</a>';
                }
                $i++;
            }
            $retval .= '</span>';
        }
        unset($link_url, $link_name, $i);
        $retval .= '</p>';
        $retval .= '</div>';

        return $retval;
    }

    /**
     * Returns a table with variables information
     *
     * @param Data $serverStatusData Server status data
     *
     * @return string
     */
    public static function getHtmlForVariablesList(Data $serverStatusData)
    {
        $retval  = '';
        $strShowStatus = self::getDescriptions();
        /**
         * define some alerts
         */
        // name => max value before alert
        $alerts = array(
            // lower is better
            // variable => max value
            'Aborted_clients' => 0,
            'Aborted_connects' => 0,

            'Binlog_cache_disk_use' => 0,

            'Created_tmp_disk_tables' => 0,

            'Handler_read_rnd' => 0,
            'Handler_read_rnd_next' => 0,

            'Innodb_buffer_pool_pages_dirty' => 0,
            'Innodb_buffer_pool_reads' => 0,
            'Innodb_buffer_pool_wait_free' => 0,
            'Innodb_log_waits' => 0,
            'Innodb_row_lock_time_avg' => 10, // ms
            'Innodb_row_lock_time_max' => 50, // ms
            'Innodb_row_lock_waits' => 0,

            'Slow_queries' => 0,
            'Delayed_errors' => 0,
            'Select_full_join' => 0,
            'Select_range_check' => 0,
            'Sort_merge_passes' => 0,
            'Opened_tables' => 0,
            'Table_locks_waited' => 0,
            'Qcache_lowmem_prunes' => 0,

            'Qcache_free_blocks' =>
                isset($serverStatusData->status['Qcache_total_blocks'])
                ? $serverStatusData->status['Qcache_total_blocks'] / 5
                : 0,
            'Slow_launch_threads' => 0,

            // depends on Key_read_requests
            // normally lower then 1:0.01
            'Key_reads' => isset($serverStatusData->status['Key_read_requests'])
                ? (0.01 * $serverStatusData->status['Key_read_requests']) : 0,
            // depends on Key_write_requests
            // normally nearly 1:1
            'Key_writes' => isset($serverStatusData->status['Key_write_requests'])
                ? (0.9 * $serverStatusData->status['Key_write_requests']) : 0,

            'Key_buffer_fraction' => 0.5,

            // alert if more than 95% of thread cache is in use
            'Threads_cached' => isset($serverStatusData->variables['thread_cache_size'])
                ? 0.95 * $serverStatusData->variables['thread_cache_size'] : 0

            // higher is better
            // variable => min value
            //'Handler read key' => '> ',
        );

        $retval .= self::getHtmlForRenderVariables(
            $serverStatusData,
            $alerts,
            $strShowStatus
        );

        return $retval;
    }

    /**
     * Returns HTML for render variables list
     *
     * @param Data  $serverStatusData Server status data
     * @param array $alerts           Alert Array
     * @param array $strShowStatus    Status Array
     *
     * @return string
     */
    public static function getHtmlForRenderVariables(Data $serverStatusData, array $alerts, array $strShowStatus)
    {
        $retval = '<div class="responsivetable">';
        $retval  .= '<table class="data noclick" id="serverstatusvariables">';
        $retval .= '<col class="namecol" />';
        $retval .= '<col class="valuecol" />';
        $retval .= '<col class="descrcol" />';
        $retval .= '<thead>';
        $retval .= '<tr>';
        $retval .= '<th>' . __('Variable') . '</th>';
        $retval .= '<th>' . __('Value') . '</th>';
        $retval .= '<th>' . __('Description') . '</th>';
        $retval .= '</tr>';
        $retval .= '</thead>';
        $retval .= '<tbody>';

        foreach ($serverStatusData->status as $name => $value) {
            $retval .= '<tr class="' . (isset($serverStatusData->allocationMap[$name])
                    ?' s_' . $serverStatusData->allocationMap[$name]
                    : '')
                . '">';

            $retval .= '<th class="name">';
            $retval .= htmlspecialchars(str_replace('_', ' ', $name));
            // Fields containing % are calculated,
            // they can not be described in MySQL documentation
            if (mb_strpos($name, '%') === false) {
                $retval .= Util::showMySQLDocu(
                    'server-status-variables',
                    false,
                    'statvar_' . $name
                );
            }
            $retval .= '</th>';

            $retval .= '<td class="value"><span class="formatted">';
            if (isset($alerts[$name])) {
                if ($value > $alerts[$name]) {
                    $retval .= '<span class="attention">';
                } else {
                    $retval .= '<span class="allfine">';
                }
            }
            if (substr($name, -1) === '%') {
                $retval .= htmlspecialchars(
                    Util::formatNumber($value, 0, 2)
                ) . ' %';
            } elseif (strpos($name, 'Uptime') !== false) {
                $retval .= htmlspecialchars(
                    Util::timespanFormat($value)
                );
            } elseif (is_numeric($value) && $value > 1000) {
                $retval .= '<abbr title="'
                    // makes available the raw value as a title
                    . htmlspecialchars(Util::formatNumber($value, 0))
                    . '">'
                    . htmlspecialchars(Util::formatNumber($value, 3, 1))
                    . '</abbr>';
            } elseif (is_numeric($value)) {
                $retval .= htmlspecialchars(
                    Util::formatNumber($value, 3, 1)
                );
            } else {
                $retval .= htmlspecialchars($value);
            }
            if (isset($alerts[$name])) {
                $retval .= '</span>';
            }
            $retval .= '</span>';
            $retval .= '<span class="original hide">';
            if (isset($alerts[$name])) {
                if ($value > $alerts[$name]) {
                    $retval .= '<span class="attention">';
                } else {
                    $retval .= '<span class="allfine">';
                }
            }
            $retval .= htmlspecialchars($value);
            if (isset($alerts[$name])) {
                $retval .= '</span>';
            }
            $retval .= '</span>';
            $retval .= '</td>';
            $retval .= '<td class="descr">';

            if (isset($strShowStatus[$name])) {
                $retval .= $strShowStatus[$name];
            }

            if (isset($serverStatusData->links[$name])) {
                foreach ($serverStatusData->links[$name] as $link_name => $link_url) {
                    if ('doc' == $link_name) {
                        $retval .= Util::showMySQLDocu($link_url);
                    } else {
                        $retval .= ' <a href="' . $link_url . '">' . $link_name . '</a>';
                    }
                }
                unset($link_url, $link_name);
            }
            $retval .= '</td>';
            $retval .= '</tr>';
        }
        $retval .= '</tbody>';
        $retval .= '</table>';
        $retval .= '</div>';

        return $retval;
    }

    /**
     * Returns a list of variable descriptions
     *
     * @return array
     */
    public static function getDescriptions()
    {
        /**
         * Messages are built using the message name
         */
        return array(
            'Aborted_clients' => __(
                'The number of connections that were aborted because the client died'
                . ' without closing the connection properly.'
            ),
            'Aborted_connects' => __(
                'The number of failed attempts to connect to the MySQL server.'
            ),
            'Binlog_cache_disk_use' => __(
                'The number of transactions that used the temporary binary log cache'
                . ' but that exceeded the value of binlog_cache_size and used a'
                . ' temporary file to store statements from the transaction.'
            ),
            'Binlog_cache_use' => __(
                'The number of transactions that used the temporary binary log cache.'
            ),
            'Connections' => __(
                'The number of connection attempts (successful or not)'
                . ' to the MySQL server.'
            ),
            'Created_tmp_disk_tables' => __(
                'The number of temporary tables on disk created automatically by'
                . ' the server while executing statements. If'
                . ' Created_tmp_disk_tables is big, you may want to increase the'
                . ' tmp_table_size  value to cause temporary tables to be'
                . ' memory-based instead of disk-based.'
            ),
            'Created_tmp_files' => __(
                'How many temporary files mysqld has created.'
            ),
            'Created_tmp_tables' => __(
                'The number of in-memory temporary tables created automatically'
                . ' by the server while executing statements.'
            ),
            'Delayed_errors' => __(
                'The number of rows written with INSERT DELAYED for which some'
                . ' error occurred (probably duplicate key).'
            ),
            'Delayed_insert_threads' => __(
                'The number of INSERT DELAYED handler threads in use. Every'
                . ' different table on which one uses INSERT DELAYED gets'
                . ' its own thread.'
            ),
            'Delayed_writes' => __(
                'The number of INSERT DELAYED rows written.'
            ),
            'Flush_commands'  => __(
                'The number of executed FLUSH statements.'
            ),
            'Handler_commit' => __(
                'The number of internal COMMIT statements.'
            ),
            'Handler_delete' => __(
                'The number of times a row was deleted from a table.'
            ),
            'Handler_discover' => __(
                'The MySQL server can ask the NDB Cluster storage engine if it'
                . ' knows about a table with a given name. This is called discovery.'
                . ' Handler_discover indicates the number of time tables have been'
                . ' discovered.'
            ),
            'Handler_read_first' => __(
                'The number of times the first entry was read from an index. If this'
                . ' is high, it suggests that the server is doing a lot of full'
                . ' index scans; for example, SELECT col1 FROM foo, assuming that'
                . ' col1 is indexed.'
            ),
            'Handler_read_key' => __(
                'The number of requests to read a row based on a key. If this is'
                . ' high, it is a good indication that your queries and tables'
                . ' are properly indexed.'
            ),
            'Handler_read_next' => __(
                'The number of requests to read the next row in key order. This is'
                . ' incremented if you are querying an index column with a range'
                . ' constraint or if you are doing an index scan.'
            ),
            'Handler_read_prev' => __(
                'The number of requests to read the previous row in key order.'
                . ' This read method is mainly used to optimize ORDER BY … DESC.'
            ),
            'Handler_read_rnd' => __(
                'The number of requests to read a row based on a fixed position.'
                . ' This is high if you are doing a lot of queries that require'
                . ' sorting of the result. You probably have a lot of queries that'
                . ' require MySQL to scan whole tables or you have joins that'
                . ' don\'t use keys properly.'
            ),
            'Handler_read_rnd_next' => __(
                'The number of requests to read the next row in the data file.'
                . ' This is high if you are doing a lot of table scans. Generally'
                . ' this suggests that your tables are not properly indexed or that'
                . ' your queries are not written to take advantage of the indexes'
                . ' you have.'
            ),
            'Handler_rollback' => __(
                'The number of internal ROLLBACK statements.'
            ),
            'Handler_update' => __(
                'The number of requests to update a row in a table.'
            ),
            'Handler_write' => __(
                'The number of requests to insert a row in a table.'
            ),
            'Innodb_buffer_pool_pages_data' => __(
                'The number of pages containing data (dirty or clean).'
            ),
            'Innodb_buffer_pool_pages_dirty' => __(
                'The number of pages currently dirty.'
            ),
            'Innodb_buffer_pool_pages_flushed' => __(
                'The number of buffer pool pages that have been requested'
                . ' to be flushed.'
            ),
            'Innodb_buffer_pool_pages_free' => __(
                'The number of free pages.'
            ),
            'Innodb_buffer_pool_pages_latched' => __(
                'The number of latched pages in InnoDB buffer pool. These are pages'
                . ' currently being read or written or that can\'t be flushed or'
                . ' removed for some other reason.'
            ),
            'Innodb_buffer_pool_pages_misc' => __(
                'The number of pages busy because they have been allocated for'
                . ' administrative overhead such as row locks or the adaptive'
                . ' hash index. This value can also be calculated as'
                . ' Innodb_buffer_pool_pages_total - Innodb_buffer_pool_pages_free'
                . ' - Innodb_buffer_pool_pages_data.'
            ),
            'Innodb_buffer_pool_pages_total' => __(
                'Total size of buffer pool, in pages.'
            ),
            'Innodb_buffer_pool_read_ahead_rnd' => __(
                'The number of "random" read-aheads InnoDB initiated. This happens'
                . ' when a query is to scan a large portion of a table but in'
                . ' random order.'
            ),
            'Innodb_buffer_pool_read_ahead_seq' => __(
                'The number of sequential read-aheads InnoDB initiated. This'
                . ' happens when InnoDB does a sequential full table scan.'
            ),
            'Innodb_buffer_pool_read_requests' => __(
                'The number of logical read requests InnoDB has done.'
            ),
            'Innodb_buffer_pool_reads' => __(
                'The number of logical reads that InnoDB could not satisfy'
                . ' from buffer pool and had to do a single-page read.'
            ),
            'Innodb_buffer_pool_wait_free' => __(
                'Normally, writes to the InnoDB buffer pool happen in the'
                . ' background. However, if it\'s necessary to read or create a page'
                . ' and no clean pages are available, it\'s necessary to wait for'
                . ' pages to be flushed first. This counter counts instances of'
                . ' these waits. If the buffer pool size was set properly, this'
                . ' value should be small.'
            ),
            'Innodb_buffer_pool_write_requests' => __(
                'The number writes done to the InnoDB buffer pool.'
            ),
            'Innodb_data_fsyncs' => __(
                'The number of fsync() operations so far.'
            ),
            'Innodb_data_pending_fsyncs' => __(
                'The current number of pending fsync() operations.'
            ),
            'Innodb_data_pending_reads' => __(
                'The current number of pending reads.'
            ),
            'Innodb_data_pending_writes' => __(
                'The current number of pending writes.'
            ),
            'Innodb_data_read' => __(
                'The amount of data read so far, in bytes.'
            ),
            'Innodb_data_reads' => __(
                'The total number of data reads.'
            ),
            'Innodb_data_writes' => __(
                'The total number of data writes.'
            ),
            'Innodb_data_written' => __(
                'The amount of data written so far, in bytes.'
            ),
            'Innodb_dblwr_pages_written' => __(
                'The number of pages that have been written for'
                . ' doublewrite operations.'
            ),
            'Innodb_dblwr_writes' => __(
                'The number of doublewrite operations that have been performed.'
            ),
            'Innodb_log_waits' => __(
                'The number of waits we had because log buffer was too small and'
                . ' we had to wait for it to be flushed before continuing.'
            ),
            'Innodb_log_write_requests' => __(
                'The number of log write requests.'
            ),
            'Innodb_log_writes' => __(
                'The number of physical writes to the log file.'
            ),
            'Innodb_os_log_fsyncs' => __(
                'The number of fsync() writes done to the log file.'
            ),
            'Innodb_os_log_pending_fsyncs' => __(
                'The number of pending log file fsyncs.'
            ),
            'Innodb_os_log_pending_writes' => __(
                'Pending log file writes.'
            ),
            'Innodb_os_log_written' => __(
                'The number of bytes written to the log file.'
            ),
            'Innodb_pages_created' => __(
                'The number of pages created.'
            ),
            'Innodb_page_size' => __(
                'The compiled-in InnoDB page size (default 16KB). Many values are'
                . ' counted in pages; the page size allows them to be easily'
                . ' converted to bytes.'
            ),
            'Innodb_pages_read' => __(
                'The number of pages read.'
            ),
            'Innodb_pages_written' => __(
                'The number of pages written.'
            ),
            'Innodb_row_lock_current_waits' => __(
                'The number of row locks currently being waited for.'
            ),
            'Innodb_row_lock_time_avg' => __(
                'The average time to acquire a row lock, in milliseconds.'
            ),
            'Innodb_row_lock_time' => __(
                'The total time spent in acquiring row locks, in milliseconds.'
            ),
            'Innodb_row_lock_time_max' => __(
                'The maximum time to acquire a row lock, in milliseconds.'
            ),
            'Innodb_row_lock_waits' => __(
                'The number of times a row lock had to be waited for.'
            ),
            'Innodb_rows_deleted' => __(
                'The number of rows deleted from InnoDB tables.'
            ),
            'Innodb_rows_inserted' => __(
                'The number of rows inserted in InnoDB tables.'
            ),
            'Innodb_rows_read' => __(
                'The number of rows read from InnoDB tables.'
            ),
            'Innodb_rows_updated' => __(
                'The number of rows updated in InnoDB tables.'
            ),
            'Key_blocks_not_flushed' => __(
                'The number of key blocks in the key cache that have changed but'
                . ' haven\'t yet been flushed to disk. It used to be known as'
                . ' Not_flushed_key_blocks.'
            ),
            'Key_blocks_unused' => __(
                'The number of unused blocks in the key cache. You can use this'
                . ' value to determine how much of the key cache is in use.'
            ),
            'Key_blocks_used' => __(
                'The number of used blocks in the key cache. This value is a'
                . ' high-water mark that indicates the maximum number of blocks'
                . ' that have ever been in use at one time.'
            ),
            'Key_buffer_fraction_%' => __(
                'Percentage of used key cache (calculated value)'
            ),
            'Key_read_requests' => __(
                'The number of requests to read a key block from the cache.'
            ),
            'Key_reads' => __(
                'The number of physical reads of a key block from disk. If Key_reads'
                . ' is big, then your key_buffer_size value is probably too small.'
                . ' The cache miss rate can be calculated as'
                . ' Key_reads/Key_read_requests.'
            ),
            'Key_read_ratio_%' => __(
                'Key cache miss calculated as rate of physical reads compared'
                . ' to read requests (calculated value)'
            ),
            'Key_write_requests' => __(
                'The number of requests to write a key block to the cache.'
            ),
            'Key_writes' => __(
                'The number of physical writes of a key block to disk.'
            ),
            'Key_write_ratio_%' => __(
                'Percentage of physical writes compared'
                . ' to write requests (calculated value)'
            ),
            'Last_query_cost' => __(
                'The total cost of the last compiled query as computed by the query'
                . ' optimizer. Useful for comparing the cost of different query'
                . ' plans for the same query. The default value of 0 means that'
                . ' no query has been compiled yet.'
            ),
            'Max_used_connections' => __(
                'The maximum number of connections that have been in use'
                . ' simultaneously since the server started.'
            ),
            'Not_flushed_delayed_rows' => __(
                'The number of rows waiting to be written in INSERT DELAYED queues.'
            ),
            'Opened_tables' => __(
                'The number of tables that have been opened. If opened tables is'
                . ' big, your table cache value is probably too small.'
            ),
            'Open_files' => __(
                'The number of files that are open.'
            ),
            'Open_streams' => __(
                'The number of streams that are open (used mainly for logging).'
            ),
            'Open_tables' => __(
                'The number of tables that are open.'
            ),
            'Qcache_free_blocks' => __(
                'The number of free memory blocks in query cache. High numbers can'
                . ' indicate fragmentation issues, which may be solved by issuing'
                . ' a FLUSH QUERY CACHE statement.'
            ),
            'Qcache_free_memory' => __(
                'The amount of free memory for query cache.'
            ),
            'Qcache_hits' => __(
                'The number of cache hits.'
            ),
            'Qcache_inserts' => __(
                'The number of queries added to the cache.'
            ),
            'Qcache_lowmem_prunes' => __(
                'The number of queries that have been removed from the cache to'
                . ' free up memory for caching new queries. This information can'
                . ' help you tune the query cache size. The query cache uses a'
                . ' least recently used (LRU) strategy to decide which queries'
                . ' to remove from the cache.'
            ),
            'Qcache_not_cached' => __(
                'The number of non-cached queries (not cachable, or not cached'
                . ' due to the query_cache_type setting).'
            ),
            'Qcache_queries_in_cache' => __(
                'The number of queries registered in the cache.'
            ),
            'Qcache_total_blocks' => __(
                'The total number of blocks in the query cache.'
            ),
            'Rpl_status' => __(
                'The status of failsafe replication (not yet implemented).'
            ),
            'Select_full_join' => __(
                'The number of joins that do not use indexes. If this value is'
                . ' not 0, you should carefully check the indexes of your tables.'
            ),
            'Select_full_range_join' => __(
                'The number of joins that used a range search on a reference table.'
            ),
            'Select_range_check' => __(
                'The number of joins without keys that check for key usage after'
                . ' each row. (If this is not 0, you should carefully check the'
                . ' indexes of your tables.)'
            ),
            'Select_range' => __(
                'The number of joins that used ranges on the first table. (It\'s'
                . ' normally not critical even if this is big.)'
            ),
            'Select_scan' => __(
                'The number of joins that did a full scan of the first table.'
            ),
            'Slave_open_temp_tables' => __(
                'The number of temporary tables currently'
                . ' open by the slave SQL thread.'
            ),
            'Slave_retried_transactions' => __(
                'Total (since startup) number of times the replication slave SQL'
                . ' thread has retried transactions.'
            ),
            'Slave_running' => __(
                'This is ON if this server is a slave that is connected to a master.'
            ),
            'Slow_launch_threads' => __(
                'The number of threads that have taken more than slow_launch_time'
                . ' seconds to create.'
            ),
            'Slow_queries' => __(
                'The number of queries that have taken more than long_query_time'
                . ' seconds.'
            ),
            'Sort_merge_passes' => __(
                'The number of merge passes the sort algorithm has had to do.'
                . ' If this value is large, you should consider increasing the'
                . ' value of the sort_buffer_size system variable.'
            ),
            'Sort_range' => __(
                'The number of sorts that were done with ranges.'
            ),
            'Sort_rows' => __(
                'The number of sorted rows.'
            ),
            'Sort_scan' => __(
                'The number of sorts that were done by scanning the table.'
            ),
            'Table_locks_immediate' => __(
                'The number of times that a table lock was acquired immediately.'
            ),
            'Table_locks_waited' => __(
                'The number of times that a table lock could not be acquired'
                . ' immediately and a wait was needed. If this is high, and you have'
                . ' performance problems, you should first optimize your queries,'
                . ' and then either split your table or tables or use replication.'
            ),
            'Threads_cached' => __(
                'The number of threads in the thread cache. The cache hit rate can'
                . ' be calculated as Threads_created/Connections. If this value is'
                . ' red you should raise your thread_cache_size.'
            ),
            'Threads_connected' => __(
                'The number of currently open connections.'
            ),
            'Threads_created' => __(
                'The number of threads created to handle connections. If'
                . ' Threads_created is big, you may want to increase the'
                . ' thread_cache_size value. (Normally this doesn\'t give a notable'
                . ' performance improvement if you have a good thread'
                . ' implementation.)'
            ),
            'Threads_cache_hitrate_%' => __(
                'Thread cache hit rate (calculated value)'
            ),
            'Threads_running' => __(
                'The number of threads that are not sleeping.'
            )
        );
    }
}
