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MDL-33018 add general index type hints and use PostgreSQL varchar_pattern_ops index type for context.path

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This significantly improves performance of accesslib queries,
credit for the discovery of this solution goes to Andrew Masterton from OU.
This commit is contained in:
Petr Skoda
2012-07-06 08:19:39 +02:00
committed by Petr Škoda
parent 2cbdaa77ea
commit bd991d03cf
15 changed files with 191 additions and 23 deletions
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lib/ddl/postgres_sql_generator.php
+34 -2
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@@ -118,6 +118,37 @@ class postgres_sql_generator extends sql_generator {
return $sqlarr;
}
/**
* Given one correct xmldb_index, returns the SQL statements
* needed to create it (in array).
*
* @param xmldb_table $xmldb_table The xmldb_table instance to create the index on.
* @param xmldb_index $xmldb_index The xmldb_index to create.
* @return array An array of SQL statements to create the index.
* @throws coding_exception Thrown if the xmldb_index does not validate with the xmldb_table.
*/
public function getCreateIndexSQL($xmldb_table, $xmldb_index) {
$sqls = parent::getCreateIndexSQL($xmldb_table, $xmldb_index);
$hints = $xmldb_index->getHints();
$fields = $xmldb_index->getFields();
if (in_array('varchar_pattern_ops', $hints) and count($fields) == 1) {
// Add the pattern index and keep the normal one.
foreach ($sqls as $sql) {
$field = reset($fields);
$count = 0;
$newindex = preg_replace("/^CREATE INDEX ([a-z0-9_]+) ON ([a-z0-9_]+) \($field\)$/", "CREATE INDEX \\1_pattern ON \\2 USING btree ($field varchar_pattern_ops)", $sql, -1, $count);
if ($count != 1) {
debugging('Unexpected getCreateIndexSQL() structure.');
continue;
}
$sqls[] = $newindex;
}
}
return $sqls;
}
/**
* Given one XMLDB Type, length and decimals, returns the DB proper SQL type.
*
@@ -306,7 +337,7 @@ class postgres_sql_generator extends sql_generator {
$results[] = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $fieldname . ' DROP DEFAULT'; // Drop default clause
}
$alterstmt = 'ALTER TABLE ' . $tablename . ' ALTER COLUMN ' . $this->getEncQuoted($xmldb_field->getName()) .
' TYPE' . $this->getFieldSQL($xmldb_table, $xmldb_field, null, true, true, null, false);
' TYPE' . $this->getFieldSQL($xmldb_table, $xmldb_field, null, true, true, null, false);
// Some castings must be performed explicitly (mainly from text|char to numeric|integer)
if (($oldmetatype == 'C' || $oldmetatype == 'X') &&
($xmldb_field->getType() == XMLDB_TYPE_NUMBER || $xmldb_field->getType() == XMLDB_TYPE_FLOAT)) {
@@ -417,7 +448,7 @@ class postgres_sql_generator extends sql_generator {
if (!$this->mdb->get_record_sql("SELECT *
FROM pg_class
WHERE relname = ? AND relkind = 'S'",
array($sequencename))) {
array($sequencename))) {
$sequencename = false;
}
@@ -475,6 +506,7 @@ class postgres_sql_generator extends sql_generator {
*/
public static function getReservedWords() {
// This file contains the reserved words for PostgreSQL databases
// This file contains the reserved words for PostgreSQL databases
// http://www.postgresql.org/docs/current/static/sql-keywords-appendix.html
$reserved_words = array (
'all', 'analyse', 'analyze', 'and', 'any', 'array', 'as', 'asc',