protected static function MakeSelectStructure(DBObjectSearch $oFilter, $aOrderBy, $aArgs, $aAttToLoad, $aExtendedDataSpec, $iLimitCount, $iLimitStart, $bGetCount, $aGroupByExpr = null)
{
// Hide objects that are not visible to the current user
//
if (!$oFilter->IsAllDataAllowed() && !$oFilter->IsDataFiltered()) {
$oVisibleObjects = UserRights::GetSelectFilter($oFilter->GetClass(), $oFilter->GetModifierProperties('UserRightsGetSelectFilter'));
if ($oVisibleObjects === false) {
// Make sure this is a valid search object, saying NO for all
$oVisibleObjects = DBObjectSearch::FromEmptySet($oFilter->GetClass());
}
if (is_object($oVisibleObjects)) {
$oFilter->MergeWith($oVisibleObjects);
$oFilter->SetDataFiltered();
} else {
// should be true at this point, meaning that no additional filtering
// is required
}
}
// Compute query modifiers properties (can be set in the search itself, by the context, etc.)
//
$aModifierProperties = self::MakeModifierProperties($oFilter);
// Create a unique cache id
//
if (self::$m_bQueryCacheEnabled || self::$m_bTraceQueries) {
// Need to identify the query
$sOqlQuery = $oFilter->ToOql();
if (count($aModifierProperties)) {
array_multisort($aModifierProperties);
$sModifierProperties = json_encode($aModifierProperties);
} else {
$sModifierProperties = '';
}
$sRawId = $sOqlQuery . $sModifierProperties;
if (!is_null($aAttToLoad)) {
$sRawId .= json_encode($aAttToLoad);
}
if (!is_null($aGroupByExpr)) {
foreach ($aGroupByExpr as $sAlias => $oExpr) {
$sRawId .= 'g:' . $sAlias . '!' . $oExpr->Render();
}
}
$sRawId .= $bGetCount;
$sOqlId = md5($sRawId);
} else {
$sOqlQuery = "SELECTING... " . $oFilter->GetClass();
$sOqlId = "query id ? n/a";
}
// Query caching
//
if (self::$m_bQueryCacheEnabled) {
// Warning: using directly the query string as the key to the hash array can FAIL if the string
// is long and the differences are only near the end... so it's safer (but not bullet proof?)
// to use a hash (like md5) of the string as the key !
//
// Example of two queries that were found as similar by the hash array:
// SELECT SLT JOIN lnkSLTToSLA AS L1 ON L1.slt_id=SLT.id JOIN SLA ON L1.sla_id = SLA.id JOIN lnkContractToSLA AS L2 ON L2.sla_id = SLA.id JOIN CustomerContract ON L2.contract_id = CustomerContract.id WHERE SLT.ticket_priority = 1 AND SLA.service_id = 3 AND SLT.metric = 'TTO' AND CustomerContract.customer_id = 2
// and
// SELECT SLT JOIN lnkSLTToSLA AS L1 ON L1.slt_id=SLT.id JOIN SLA ON L1.sla_id = SLA.id JOIN lnkContractToSLA AS L2 ON L2.sla_id = SLA.id JOIN CustomerContract ON L2.contract_id = CustomerContract.id WHERE SLT.ticket_priority = 1 AND SLA.service_id = 3 AND SLT.metric = 'TTR' AND CustomerContract.customer_id = 2
// the only difference is R instead or O at position 285 (TTR instead of TTO)...
//
if (array_key_exists($sOqlId, self::$m_aQueryStructCache)) {
// hit!
$oSelect = unserialize(serialize(self::$m_aQueryStructCache[$sOqlId]));
// Note: cloning is not enough because the subtree is made of objects
} elseif (self::$m_bUseAPCCache) {
// Note: For versions of APC older than 3.0.17, fetch() accepts only one parameter
//
$sOqlAPCCacheId = 'itop-' . MetaModel::GetEnvironmentId() . '-query-cache-' . $sOqlId;
$oKPI = new ExecutionKPI();
$result = apc_fetch($sOqlAPCCacheId);
$oKPI->ComputeStats('Query APC (fetch)', $sOqlQuery);
if (is_object($result)) {
$oSelect = $result;
self::$m_aQueryStructCache[$sOqlId] = $oSelect;
}
}
}
if (!isset($oSelect)) {
$oBuild = new QueryBuilderContext($oFilter, $aModifierProperties, $aGroupByExpr);
$oKPI = new ExecutionKPI();
$oSelect = self::MakeQuery($oBuild, $oFilter, $aAttToLoad, array(), true);
$oSelect->SetCondition($oBuild->m_oQBExpressions->GetCondition());
$oSelect->SetSourceOQL($sOqlQuery);
if ($aGroupByExpr) {
$aCols = $oBuild->m_oQBExpressions->GetGroupBy();
$oSelect->SetGroupBy($aCols);
$oSelect->SetSelect($aCols);
} else {
$oSelect->SetSelect($oBuild->m_oQBExpressions->GetSelect());
}
if (self::$m_bOptimizeQueries) {
if ($bGetCount) {
// Simplify the query if just getting the count
$oSelect->SetSelect(array());
}
$oBuild->m_oQBExpressions->GetMandatoryTables($aMandatoryTables);
$oSelect->OptimizeJoins($aMandatoryTables);
}
$oKPI->ComputeStats('MakeQuery (select)', $sOqlQuery);
if (self::$m_bQueryCacheEnabled) {
if (self::$m_bUseAPCCache) {
$oKPI = new ExecutionKPI();
apc_store($sOqlAPCCacheId, $oSelect, self::$m_iQueryCacheTTL);
$oKPI->ComputeStats('Query APC (store)', $sOqlQuery);
}
self::$m_aQueryStructCache[$sOqlId] = $oSelect->DeepClone();
}
}
// Join to an additional table, if required...
//
if ($aExtendedDataSpec != null) {
$sTableAlias = '_extended_data_';
$aExtendedFields = array();
foreach ($aExtendedDataSpec['fields'] as $sColumn) {
$sColRef = $oFilter->GetClassAlias() . '_extdata_' . $sColumn;
$aExtendedFields[$sColRef] = new FieldExpressionResolved($sColumn, $sTableAlias);
}
$oSelectExt = new SQLQuery($aExtendedDataSpec['table'], $sTableAlias, $aExtendedFields);
$oSelect->AddInnerJoin($oSelectExt, 'id', $aExtendedDataSpec['join_key']);
}
return $oSelect;
}