// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void SimpleDeadCodeElimination::AddIndexes(Operand* op, LoadStoreInfo& info,
Variable* variable, bool isStore) {
if(auto variableRef = op->As<VariableReference>()) {
if(variableRef->GetVariable() == variable) {
// Found the base variable.
info.Valid = true;
}
return;
}
else if(auto indexInstr = op->DefiningInstrAs<IndexInstr>()) {
// Check if we have a constant index.
if(auto intConst = indexInstr->IndexOp()->As<IntConstant>()) {
info.IndexList.Add(intConst->Value());
}
else info.HasVariableIndex = true;
AddIndexes(indexInstr->BaseOp(), info, variable, isStore);
return;
}
else if(auto elemInstr = op->DefiningInstrAs<ElementInstr>()) {
info.IndexList.Add(elemInstr->GetFieldIndex());
AddIndexes(elemInstr->BaseOp(), info, variable, isStore);
return;
}
else if(isStore == false) {
// Keep track of 'addr' and 'ptop' that lead to the variable,
// because they keep alive any store.
if(auto addrInstr = op->DefiningInstrAs<AddressInstr>()) {
info.HasVariableIndex = true;
AddIndexes(addrInstr->BaseOp(), info, variable, isStore);
}
else if(auto ptopInstr = op->DefiningInstrAs<PtopInstr>()) {
info.HasVariableIndex = true;
AddIndexes(ptopInstr->TargetOp(), info, variable, isStore);
}
return;
}
// Any other instruction renders the 'store' invalid.
info.Valid = false;
}
void IndexTuner::Analyze(storage::DataTable* table) {
// Process all samples in table
auto& samples = table->GetIndexSamples();
auto sample_count = samples.size();
// Check if we have sufficient number of samples
if (sample_count < sample_count_threshold) {
return;
}
// Check write ratio
auto average_write_ratio = ComputeWorkloadWriteRatio(samples);
// Determine frequent samples
auto sample_frequency_entry_list = GetFrequentSamples(samples);
// Compute suggested indices
auto suggested_indices = GetSuggestedIndices(sample_frequency_entry_list);
// Check index storage footprint
auto max_indexes_allowed = CheckIndexStorageFootprint(table);
// Drop indexes if needed
auto index_creation_constraint = (max_indexes_allowed <= 0);
auto write_intensive_workload = (average_write_ratio > write_ratio_threshold);
if (index_creation_constraint == true || write_intensive_workload == true) {
DropIndexes(table);
}
// Add indexes if needed
AddIndexes(table, suggested_indices, max_indexes_allowed);
// Clear all current samples in table
table->ClearIndexSamples();
// Update index utility
UpdateIndexUtility(table, sample_frequency_entry_list);
// Display index information
PrintIndexInformation(table);
}
