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MDL-24962 backup - cache xmldb_tables for multiple operations. Apply destroyer to temp controller.

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This commit is contained in:
Eloy Lafuente 2010-11-15 07:17:24 +00:00
parent ab1c069e11
commit f2364c93ed
1 changed files with 41 additions and 26 deletions
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67
backup/util/dbops/backup_controller_dbops.class.php
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@ -95,35 +95,48 @@ abstract class backup_controller_dbops extends backup_dbops {
global $CFG, $DB;
$dbman = $DB->get_manager(); // We are going to use database_manager services
// Note: For now we are going to load the realtablename from core lib/db/install.xml
// that way, any change in the "template" will be applied here automatically. If this causes
// too much slow, we can always forget about the template and keep maintained the xmldb_table
// structure inline - manually - here.
// TODO: Right now, loading the whole lib/db/install.xml is "eating" 10M, we should
// change our way here in order to decrease that memory usage
$templatetablename = $realtablename;
$targettablename = $temptablename;
$xmlfile = $CFG->dirroot . '/lib/db/install.xml';
$xmldb_file = new xmldb_file($xmlfile);
if (!$xmldb_file->fileExists()) {
throw new ddl_exception('ddlxmlfileerror', null, 'File does not exist');
}
$loaded = $xmldb_file->loadXMLStructure();
if (!$loaded || !$xmldb_file->isLoaded()) {
throw new ddl_exception('ddlxmlfileerror', null, 'not loaded??');
}
$xmldb_structure = $xmldb_file->getStructure();
$xmldb_table = $xmldb_structure->getTable($templatetablename);
if (is_null($xmldb_table)) {
throw new ddl_exception('ddlunknowntable', null, 'The table ' . $templatetablename . ' is not defined in file ' . $xmlfile);
// As far as xmldb objects use a lot of circular references (prev and next) and we aren't destroying
// them at all, that causes one memory leak of about 3M per backup execution, not problematic for
// individual backups but critical for automated (multiple) ones.
// So we are statically caching the xmldb_table definition here to produce the leak "only" once
static $xmldb_tables = array();
// Not cached, get it
if (!isset($xmldb_tables[$realtablename])) {
// Note: For now we are going to load the realtablename from core lib/db/install.xml
// that way, any change in the "template" will be applied here automatically. If this causes
// too much slow, we can always forget about the template and keep maintained the xmldb_table
// structure inline - manually - here.
// TODO: Right now, loading the whole lib/db/install.xml is "eating" 10M, we should
// change our way here in order to decrease that memory usage
$templatetablename = $realtablename;
$targettablename = $temptablename;
$xmlfile = $CFG->dirroot . '/lib/db/install.xml';
$xmldb_file = new xmldb_file($xmlfile);
if (!$xmldb_file->fileExists()) {
throw new ddl_exception('ddlxmlfileerror', null, 'File does not exist');
}
$loaded = $xmldb_file->loadXMLStructure();
if (!$loaded || !$xmldb_file->isLoaded()) {
throw new ddl_exception('ddlxmlfileerror', null, 'not loaded??');
}
$xmldb_structure = $xmldb_file->getStructure();
$xmldb_table = $xmldb_structure->getTable($templatetablename);
if (is_null($xmldb_table)) {
throw new ddl_exception('ddlunknowntable', null, 'The table ' . $templatetablename . ' is not defined in file ' . $xmlfile);
}
// Clean prev & next, we are alone
$xmldb_table->setNext(null);
$xmldb_table->setPrevious(null);
// Rename
$xmldb_table->setName($targettablename);
// Cache it
$xmldb_tables[$realtablename] = $xmldb_table;
}
// Arrived here, we have the table always in static cache, get it
$xmldb_table = $xmldb_tables[$realtablename];
// Set default backupid (not needed but this enforce any missing backupid). That's hackery in action!
$xmldb_table->getField('backupid')->setDefault($backupid);
// Clean prev & next, we are alone
$xmldb_table->setNext(null);
$xmldb_table->setPrevious(null);
// Rename
$xmldb_table->setName($targettablename);
$dbman->create_temp_table($xmldb_table); // And create it
}
@ -344,6 +357,8 @@ abstract class backup_controller_dbops extends backup_dbops {
}
}
$bc->destroy(); // Always need to destroy controller to handle circular references
return array(array((object)$detailsinfo), $contentsinfo, $settingsinfo);
}