public override CGroupMember Apply(CGroupMember expr)
{
var log = expr.logic_ as LogicJoinBlock;
var solver = new DPccp();
var joinplan = solver.Reset().Run(log.graph_);
return(new CGroupMember(joinplan, expr.group_));
}
static public void Test()
{
DPccp solver = new DPccp();
// book figure 3.12
var tables = new string[] { "T1", "T2", "T3", "T4", "T5" };
JoinGraph figure312 = new JoinGraph(tables, new string[] { "T1*T2", "T1*T3", "T1*T4", "T3*T4", "T5*T2", "T5*T3", "T5*T4" });
Debug.Assert(figure312.joinbits_.Count == 5 && figure312.preds_.Count == 7);
solver.Reset().Run(figure312);
// full test
DoTest(new DPccp());
}
override internal PhysicNode Run(JoinGraph graph, BigInteger expectC1)
{
int ntables = graph.vertices_.Count;
var Trees = new List <PhysicNode>();
Console.WriteLine("GOO #tables: " + ntables);
// Treees = {R1, R2, ..., Rn}
graph_ = graph;
foreach (var logic in graph.vertices_)
{
BitVector contained = 1 << graph.vertices_.IndexOf(logic);
logic.tableContained_ = contained;
if (graph.memo_ is null)
{
Trees.Add(new PhysicScanTable(logic));
}
else
{
// vertices are already inserted into memo
var cgroup = graph.memo_.LookupCGroup(logic);
var logicref = new LogicMemoRef(cgroup);
Trees.Add(new PhysicMemoRef(logicref));
}
}
while (Trees.Count != 1)
{
PhysicNode Ti = null, Tj = null;
PhysicNode bestJoin = null;
// find Ti, Tj in Trees s.t. i < j (avoid duplicates) and TixTj is minimal
for (int i = 0; i < Trees.Count; i++)
{
for (int j = i + 1; j < Trees.Count; j++)
{
var join = CreateMinimalJoinTree(Trees[i], Trees[j], true);
if (bestJoin == null || join.Cost() < bestJoin.Cost())
{
bestJoin = join;
Ti = Trees[i];
Tj = Trees[j];
}
}
}
Debug.Assert(Ti != null && Tj != null);
Trees.Remove(Ti); Trees.Remove(Tj);
Trees.Add(bestJoin);
}
// compare with DPccp solver
// ideally, DPccp shall always generate better plans since GOO is heuristic - but DPccp does not consider
// CP, so in some cases where CP is beneficial, GOO can win
//
var result = Trees[0];
var dpccp = new DPccp().Run(graph, expectC1);
Console.WriteLine(result);
if (dpccp.InclusiveCost() < result.InclusiveCost())
{
Console.WriteLine("warning: GOO non optimal plan: {0} vs. {1}", dpccp.InclusiveCost(), result.InclusiveCost());
}
if (dpccp.Cost() > result.Cost())
{
Console.WriteLine("warning: DPCC shall consider CP in the case: {0} vs. {1}", dpccp.InclusiveCost(), result.InclusiveCost());
}
return(result);
}