Commit e7c02846 authored by catch's avatar catch

Issue #2921855 by daffie: Default Database Schema::findTables() is slow for PostgreSQL

parent 6c724f8f
......@@ -472,6 +472,52 @@ public function tableExists($table) {
return (bool) $this->connection->query("SELECT 1 FROM pg_tables WHERE schemaname = :schema AND tablename = :table", [':schema' => $prefixInfo['schema'], ':table' => $prefixInfo['table']])->fetchField();
}
/**
* {@inheritdoc}
*/
public function findTables($table_expression) {
$individually_prefixed_tables = $this->connection->getUnprefixedTablesMap();
$default_prefix = $this->connection->tablePrefix();
$default_prefix_length = strlen($default_prefix);
$tables = [];
// Load all the tables up front in order to take into account per-table
// prefixes. The actual matching is done at the bottom of the method.
$results = $this->connection->query("SELECT tablename FROM pg_tables WHERE schemaname = :schema", [':schema' => $this->defaultSchema]);
foreach ($results as $table) {
// Take into account tables that have an individual prefix.
if (isset($individually_prefixed_tables[$table->tablename])) {
$prefix_length = strlen($this->connection->tablePrefix($individually_prefixed_tables[$table->tablename]));
}
elseif ($default_prefix && substr($table->tablename, 0, $default_prefix_length) !== $default_prefix) {
// This table name does not start the default prefix, which means that
// it is not managed by Drupal so it should be excluded from the result.
continue;
}
else {
$prefix_length = $default_prefix_length;
}
// Remove the prefix from the returned tables.
$unprefixed_table_name = substr($table->tablename, $prefix_length);
// The pattern can match a table which is the same as the prefix. That
// will become an empty string when we remove the prefix, which will
// probably surprise the caller, besides not being a prefixed table. So
// remove it.
if (!empty($unprefixed_table_name)) {
$tables[$unprefixed_table_name] = $unprefixed_table_name;
}
}
// Convert the table expression from its SQL LIKE syntax to a regular
// expression and escape the delimiter that will be used for matching.
$table_expression = str_replace(['%', '_'], ['.*?', '.'], preg_quote($table_expression, '/'));
$tables = preg_grep('/^' . $table_expression . '$/i', $tables);
return $tables;
}
/**
* {@inheritdoc}
*/
......
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