private boolean hasEqualityConstraints(int startPos, int endPos) {
ScanRanges ranges = context.getScanRanges();
// If a GROUP BY is being done, then the rows are ordered according to the GROUP BY key,
// not by the original row key order of the table (see PHOENIX-3451).
// We check each GROUP BY expression to see if it only references columns that are
// matched by equality constraints, in which case the expression itself would be constant.
// FIXME: this only recognizes row key columns that are held constant, not all columns.
// FIXME: we should optimize out any GROUP BY or ORDER BY expression which is deemed to
// be held constant based on the WHERE clause.
if (!groupBy.isEmpty()) {
for (int pos = startPos; pos < endPos; pos++) {
IsConstantVisitor visitor = new IsConstantVisitor(this.projector, ranges);
List<Expression> groupByExpressions = groupBy.getExpressions();
if (pos >= groupByExpressions.size()) { // sanity check - shouldn't be necessary
return false;
}
Expression groupByExpression = groupByExpressions.get(pos);
if (groupByExpression.getDeterminism().ordinal() > Determinism.PER_STATEMENT.ordinal()) {
return false;
}
Boolean isConstant = groupByExpression.accept(visitor);
if (!Boolean.TRUE.equals(isConstant)) {
return false;
}
}
return true;
}
for (int pos = startPos; pos < endPos; pos++) {
if (!ranges.hasEqualityConstraint(pos)) {
return false;
}
}
return true;
}
public OrderPreservingTracker(
StatementContext context,
GroupBy groupBy,
Ordering ordering,
int nNodes,
TupleProjector projector) {
this.context = context;
if (groupBy.isEmpty()) {
PTable table = context.getResolver().getTables().get(0).getTable();
this.isOrderPreserving = table.rowKeyOrderOptimizable();
boolean isSalted = table.getBucketNum() != null;
boolean isMultiTenant =
context.getConnection().getTenantId() != null && table.isMultiTenant();
boolean isSharedViewIndex = table.getViewIndexId() != null;
// TODO: util for this offset, as it's computed in numerous places
this.pkPositionOffset =
(isSalted ? 1 : 0) + (isMultiTenant ? 1 : 0) + (isSharedViewIndex ? 1 : 0);
} else {
this.isOrderPreserving = true;
this.pkPositionOffset = 0;
}
this.groupBy = groupBy;
this.visitor = new TrackOrderPreservingExpressionVisitor(projector);
this.orderPreservingInfos = Lists.newArrayListWithExpectedSize(nNodes);
this.ordering = ordering;
this.projector = projector;
}
protected void explain(String prefix, List<String> planSteps) {
StringBuilder buf = new StringBuilder(prefix);
ScanRanges scanRanges = context.getScanRanges();
boolean hasSkipScanFilter = false;
if (scanRanges.isEverything()) {
buf.append("FULL SCAN ");
} else {
hasSkipScanFilter = explainSkipScan(buf);
}
buf.append("OVER " + tableRef.getTable().getName().getString());
if (!scanRanges.isPointLookup()) {
appendKeyRanges(buf);
}
planSteps.add(buf.toString());
Scan scan = context.getScan();
Filter filter = scan.getFilter();
PageFilter pageFilter = null;
if (filter != null) {
int offset = 0;
boolean hasFirstKeyOnlyFilter = false;
String filterDesc = "";
if (hasSkipScanFilter) {
if (filter instanceof FilterList) {
List<Filter> filterList = ((FilterList) filter).getFilters();
if (filterList.get(0) instanceof FirstKeyOnlyFilter) {
hasFirstKeyOnlyFilter = true;
offset = 1;
}
if (filterList.size() > offset + 1) {
filterDesc = filterList.get(offset + 1).toString();
if (filterList.size() > offset + 2) {
pageFilter = (PageFilter) filterList.get(offset + 2);
}
}
}
} else if (filter instanceof FilterList) {
List<Filter> filterList = ((FilterList) filter).getFilters();
if (filterList.get(0) instanceof FirstKeyOnlyFilter) {
hasFirstKeyOnlyFilter = true;
offset = 1;
}
if (filterList.size() > offset) {
filterDesc = filterList.get(offset).toString();
if (filterList.size() > offset + 1) {
pageFilter = (PageFilter) filterList.get(offset + 1);
}
}
} else {
if (filter instanceof FirstKeyOnlyFilter) {
hasFirstKeyOnlyFilter = true;
} else {
filterDesc = filter.toString();
}
}
if (filterDesc.length() > 0) {
planSteps.add(
" SERVER FILTER BY "
+ (hasFirstKeyOnlyFilter ? "FIRST KEY ONLY AND " : "")
+ filterDesc);
} else if (hasFirstKeyOnlyFilter) {
planSteps.add(" SERVER FILTER BY FIRST KEY ONLY");
}
if (pageFilter != null) {
planSteps.add(" SERVER " + pageFilter.getPageSize() + " ROW LIMIT");
}
}
groupBy.explain(planSteps);
}