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FIX Calculate threshold condition with SQL rather than PHP

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This is a performance fix. Modern SQL engines can avoid counting a whole result set (potentially thousands of records) when you are only interested if the count exceeds a threshold.
This commit is contained in:
Guy Marriott 2019-04-15 11:36:57 +12:00
parent f2f28586d9
commit a48beac845
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1 changed files with 17 additions and 2 deletions
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19
src/ORM/FieldType/DBForeignKey.php
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@ -87,12 +87,27 @@ class DBForeignKey extends DBInt
// Add the count of the list to a cache for subsequent calls
if (!isset(static::$foreignListCache[$hasOneClass])) {
// Let the DB do the threshold check as it will be faster - depending on the SQL engine it might only have
// to count indexes
$dataQuery = $list->dataQuery()->getFinalisedQuery();
// Clear order-by as it's not relevant for counts
$dataQuery->setOrderBy(false);
// Remove distinct. Applying distinct shouldn't be required provided relations are not applied.
$dataQuery->setDistinct(false);
$dataQuery->setSelect(['over_threshold' => 'count(*) > ' . (int) $threshold]);
$result = $dataQuery->execute()->column('over_threshold');
$overThreshold = !empty($result) && ($result[0] === 't' || (int) $result[0] === 1);
static::$foreignListCache[$hasOneClass] = [
'count' => $list->count(),
'overThreshold' => $overThreshold,
];
}
if (static::$foreignListCache[$hasOneClass]['count'] < $threshold) {
$overThreshold = static::$foreignListCache[$hasOneClass]['overThreshold'];
if (!$overThreshold) {
// Add the mapped list for the cache
if (!isset(static::$foreignListCache[$hasOneClass]['map'])) {
static::$foreignListCache[$hasOneClass]['map'] = $list->map('ID', $titleField);