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Posted to notifications@asterixdb.apache.org by AsterixDB Code Review <do...@asterix-gerrit.ics.uci.edu> on 2025/09/18 18:56:27 UTC
[M] Change in asterixdb[phoenix]: [ASTERIXDB-3635][COMP] Tune single dataset index costing
From <mu...@couchbase.com>:
murali.krishna@couchbase.com has uploaded this change for review. ( https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/20393?usp=email )
Change subject: [ASTERIXDB-3635][COMP] Tune single dataset index costing
......................................................................
[ASTERIXDB-3635][COMP] Tune single dataset index costing
Change-Id: If2ed184e1dbc941ee53718e09331cbf7011370ae
---
M asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinNode.java
1 file changed, 34 insertions(+), 73 deletions(-)
git pull ssh://asterix-gerrit.ics.uci.edu:29418/asterixdb refs/changes/93/20393/1
diff --git a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinNode.java b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinNode.java
index 5cbb6f8..c71009a 100644
--- a/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinNode.java
+++ b/asterixdb/asterix-algebra/src/main/java/org/apache/asterix/optimizer/rules/cbo/JoinNode.java
@@ -730,99 +730,63 @@
private void buildIndexPlans() {
List<PlanNode> allPlans = joinEnum.getAllPlans();
PlanNode pn;
- ICost opCost, totalCost;
+ double ic, dc, tc, oc; // for debugging
+
List<Triple<Index, Double, AbstractFunctionCallExpression>> mandatoryIndexesInfo = new ArrayList<>();
List<Triple<Index, Double, AbstractFunctionCallExpression>> optionalIndexesInfo = new ArrayList<>();
double sel = 1.0;
- boolean mandatoryArrayIndexUsed = false;
- boolean optionalArrayIndexUsed = false;
- opCost = this.joinEnum.getCostHandle().zeroCost();
+
for (int i = 0; i < IndexCostInfo.size(); i++) {
if (joinEnum.findUseIndexHint(IndexCostInfo.get(i).third)) {
mandatoryIndexesInfo.add(IndexCostInfo.get(i));
- mandatoryArrayIndexUsed = mandatoryArrayIndexUsed
- || (mandatoryIndexesInfo.get(i).first.getIndexType() == DatasetConfig.IndexType.ARRAY);
} else {
optionalIndexesInfo.add(IndexCostInfo.get(i));
- optionalArrayIndexUsed = optionalArrayIndexUsed
- || (optionalIndexesInfo.get(i).first.getIndexType() == DatasetConfig.IndexType.ARRAY);
}
}
- List<ICost> indexCosts = new ArrayList<>(); // these are the costs associated with the index only
- // First cost all the mandatory indexes. These will be in the plan regardless of the cost
+ ICost indexCosts = this.joinEnum.getCostHandle().zeroCost();
+ ICost totalCost = this.joinEnum.getCostHandle().zeroCost();
+ ICost dataScanCost;
+
if (mandatoryIndexesInfo.size() > 0) {
for (int i = 0; i < mandatoryIndexesInfo.size(); i++) {
- indexCosts.add(joinEnum.getCostMethodsHandle().costIndexScan(this, mandatoryIndexesInfo.get(i).second));
+ ICost cost = joinEnum.getCostMethodsHandle().costIndexScan(this, mandatoryIndexesInfo.get(i).second);
+ if ((mandatoryIndexesInfo.get(i).first.getIndexType() == DatasetConfig.IndexType.ARRAY)) {
+ cost = cost.costAdd(cost); // double the cost for arrays.
+ }
+ indexCosts = indexCosts.costAdd(cost); // a running tally
+ sel *= mandatoryIndexesInfo.get(i).second;
}
-
- opCost = this.joinEnum.getCostHandle().zeroCost();
-
- for (int i = 0; i < mandatoryIndexesInfo.size(); i++) {
- opCost = opCost.costAdd(indexCosts.get(i)); // opCost will have all the index scan costs
- sel *= mandatoryIndexesInfo.get(i).second; // assuming selectivities are independent for now
- }
-
- // Now add the data Scan cost.
- ICost dataScanCost = joinEnum.getCostMethodsHandle().costIndexDataScan(this, sel);
- opCost = opCost.costAdd(dataScanCost); // opCost now has the total cost of all the mandatory indexes + data costs.
- if (mandatoryArrayIndexUsed) {
- opCost = opCost.costAdd(opCost);
- }
+ dataScanCost = joinEnum.getCostMethodsHandle().costIndexDataScan(this, sel);
+ totalCost = indexCosts.costAdd(dataScanCost); // this is the total cost of using the mandatory costs. This cost cannot be skipped.
}
- ICost mandatoryIndexesCost = opCost; // This will be added at the end to the total cost irrespective of optimality.
- //opCost = this.joinEnum.getCostHandle().zeroCost(); // compute cost for optional indexes and store in opCost.
- // Now lets deal with the optional indexes. These are the ones without any hints on them.
- List<ICost> dataCosts = new ArrayList<>(); // these are the costs associated with accessing the data records
- indexCosts.clear();
+ ICost opCost = totalCost;
if (optionalIndexesInfo.size() > 0) {
- optionalIndexesInfo.sort(Comparator.comparingDouble(o -> o.second)); // sort on selectivity.
+ optionalIndexesInfo.sort(Comparator.comparingDouble(o -> o.second));
- // find the costs using one index at a time first.
-
- // sel is now the selectivity of all the previous mandatory indexes.
for (int i = 0; i < optionalIndexesInfo.size(); i++) {
- indexCosts.add(joinEnum.getCostMethodsHandle().costIndexScan(this, optionalIndexesInfo.get(i).second)); // I0; I1; I2; ...
- // Now get the cost of the datascans involved with the multiplied selectivity
- // dataCost (0) will contain the dataScan cost with the first index
- //dataCost (1) will contain the dataScan cost with the first index and the 2nd index and so on.
- sel *= optionalIndexesInfo.get(i).second; // assuming selectivities are independent for now
- if (optionalIndexesInfo.get(i).first.isPrimaryIndex()) {
- dataCosts.add(joinEnum.getCostHandle().zeroCost());
- } else {
- dataCosts.add(joinEnum.getCostMethodsHandle().costIndexDataScan(this, sel)); // D0; D01; D012; ...
+ ICost cost = joinEnum.getCostMethodsHandle().costIndexScan(this, optionalIndexesInfo.get(i).second);
+ if ((optionalIndexesInfo.get(i).first.getIndexType() == DatasetConfig.IndexType.ARRAY)) {
+ cost = cost.costAdd(cost); // double the cost for arrays.
}
- }
-
- // At the of of the above loop, I0, I1, I2 ... have been computed
- // Also D0, D01, D012 ... have been computed.
-
- opCost = indexCosts.get(0).costAdd(dataCosts.get(0));
- //opCost is now the cost of the first (and cheapest) optional index plus the corresponding data scan
-
- //Intersect the first two and then the first three and so on.
- //If the cost does not decrease, then stop
-
- ICost newIdxCost = indexCosts.get(0); // I0
- ICost currentCost;
- for (int i = 1; i < optionalIndexesInfo.size(); i++) {
- newIdxCost = newIdxCost.costAdd(indexCosts.get(i)); // I0 + I1; I0 + I1 + I2
- currentCost = newIdxCost.costAdd(dataCosts.get(i)); // I0 + I1 + D01; I0 + I1 + I2 + D012
- if (currentCost.costLT(opCost) || level <= joinEnum.cboFullEnumLevel) { // save this cost and try adding one more index
- opCost = currentCost;
- } else {
- // set the selectivites of the indexes not picked to be -1.0, so we can set
- // the skp index annotations correctly
- for (int j = i; j < optionalIndexesInfo.size(); j++) {
- optionalIndexesInfo.get(j).second = -1.0;
+ indexCosts = indexCosts.costAdd(cost);
+ sel *= optionalIndexesInfo.get(i).second;
+ dataScanCost = joinEnum.getCostMethodsHandle().costIndexDataScan(this, sel);
+ opCost = indexCosts.costAdd(dataScanCost);
+ tc = totalCost.computeTotalCost();
+ if (tc > 0.0) {
+ if (opCost.costGT(totalCost)) { // we can stop here since additional indexes are not useful
+ for (int j = i; j < optionalIndexesInfo.size(); j++) {
+ optionalIndexesInfo.get(j).second = -1.0;
+ }
+ opCost = totalCost;
+ break;
}
- break; // can't get any cheaper.
+ } else {
+ totalCost = indexCosts.costAdd(dataScanCost);
}
}
- if (optionalArrayIndexUsed) {
- opCost = opCost.costAdd(opCost);
- }
}
// opCost is now the total cost of the indexes chosen along with the associated data scan cost.
@@ -832,9 +796,6 @@
}
}
- totalCost = opCost.costAdd(mandatoryIndexesCost); // cost of all the indexes chosen
- // Now check if any of the indexes were array indexes. If so double the cost
-
boolean forceEnum = mandatoryIndexesInfo.size() > 0 || level <= joinEnum.cboFullEnumLevel;
if (opCost.costLT(this.cheapestPlanCost) || forceEnum) {
pn = new PlanNode(allPlans.size(), joinEnum, this, datasetNames.get(0), leafInput);
--
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Gerrit-MessageType: newchange
Gerrit-Project: asterixdb
Gerrit-Branch: phoenix
Gerrit-Change-Id: If2ed184e1dbc941ee53718e09331cbf7011370ae
Gerrit-Change-Number: 20393
Gerrit-PatchSet: 1
Gerrit-Owner: murali.krishna@couchbase.com