public PlanItem getBestPlanItem(Session session, int[] masks, TableFilter[] filters, int filter) {
PlanItem item = new PlanItem();
item.cost = Constants.COST_ROW_OFFSET;
if (tableRule instanceof ShardedTableRule) {
ShardedTableRule shardedTableRule = (ShardedTableRule) tableRule;
int nodeCount = shardedTableRule.getObjectNodes().length;
item.cost = Constants.COST_ROW_OFFSET * nodeCount;
}
Column[] columns = getRuleColumns();
if (columns != null && masks != null) {
for (int i = 0, len = columns.length; i < len; i++) {
Column column = columns[i];
int index = column.getColumnId();
int mask = masks[index];
if ((mask & IndexCondition.EQUALITY) == IndexCondition.EQUALITY) {
if (i == columns.length - 1) {
item.cost = Constants.COST_ROW_OFFSET;
item.scanningStrategyFor(ScanningStrategy.USE_SHARDINGKEY);
break;
}
} else {
break;
}
}
}
double rowsCost = item.cost;
ArrayList<Index> indexes = getIndexes();
if (indexes != null && masks != null) {
for (Index index : indexes) {
columns = index.getColumns();
for (int i = 0, len = columns.length; i < len; i++) {
Column column = columns[i];
int columnId = column.getColumnId();
int mask = masks[columnId];
if ((mask & IndexCondition.EQUALITY) == IndexCondition.EQUALITY) {
if (i == columns.length - 1 && index.getIndexType().isUnique()) {
item.cost = rowsCost * 0.25d;
item.scanningStrategyFor(ScanningStrategy.USE_UNIQUEKEY);
break;
}
item.cost = Math.max(rowsCost * 0.5d, item.cost * 0.5d);
item.scanningStrategyFor(ScanningStrategy.USE_INDEXKEY);
} else if ((mask & IndexCondition.RANGE) == IndexCondition.RANGE) {
item.cost = item.cost * 0.70d;
item.scanningStrategyFor(ScanningStrategy.USE_INDEXKEY);
break;
} else if ((mask & IndexCondition.START) == IndexCondition.START) {
item.cost = item.cost * 0.75d;
item.scanningStrategyFor(ScanningStrategy.USE_INDEXKEY);
break;
} else if ((mask & IndexCondition.END) == IndexCondition.END) {
item.cost = item.cost * 0.75d;
item.scanningStrategyFor(ScanningStrategy.USE_INDEXKEY);
break;
} else {
break;
}
}
}
}
// validationPlanItem(item);
return item;
}
