Patch: replace Methode getCostRangeIndex in org.h2.index.BaseIndex
protected long getCostRangeIndex(int[] masks, long rowCount,
TableFilter filter, SortOrder sortOrder) {
rowCount += Constants.COST_ROW_OFFSET;
long cost = rowCount;
long rows = rowCount;
double totalSelectivity = 0;// totalSelectivity = 100 - ((100 - 1) *
// (100 - 1) / 100) = 1,99 wennn
// totalSelectivity is an int then
// totalSelectivity stay = 1
if (masks == null) {
return cost;
}
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 && getIndexType().isUnique()) {
cost = 3;
break;
}
totalSelectivity = 100 - ((100 - totalSelectivity) * (100 -
column.getSelectivity()) / 100);
long distinctRows = (long) (rowCount * totalSelectivity /
100);
if (distinctRows <= 0) {
distinctRows = 1;
}
rows = Math.max(rowCount / distinctRows, 1);
cost = 2 + rows;
} else if ((mask & IndexCondition.RANGE) ==
IndexCondition.RANGE) {
cost = 2 + rows / 4;
rows = cost;// for compare anothers columns
} else if ((mask & IndexCondition.START) ==
IndexCondition.START) {
cost = 2 + rows / 3;
rows = cost;// for compare anothers columns
} else if ((mask & IndexCondition.END) == IndexCondition.END) {
cost = rows / 3;
rows = cost;// for compare anothers columns
} else {
break;
}
}
// if the ORDER BY clause matches the ordering of this index,
// it will be cheaper than another index, so adjust the cost
accordingly
if (sortOrder != null) {
boolean sortOrderMatches = true;
int coveringCount = 0;
int[] sortTypes = sortOrder.getSortTypes();
for (int i = 0, len = sortTypes.length; i < len; i++) {
if (i >= indexColumns.length) {
// we can still use this index if we are sorting by more
// than it's columns, it's just that the coveringCount
// is lower than with an index that contains
// more of the order by columns
break;
}
Column col = sortOrder.getColumn(i, filter);
if (col == null) {
sortOrderMatches = false;
break;
}
IndexColumn indexCol = indexColumns[i];
if (col != indexCol.column) {
sortOrderMatches = false;
break;
}
int sortType = sortTypes[i];
if (sortType != indexCol.sortType) {
sortOrderMatches = false;
break;
}
coveringCount++;
}
if (sortOrderMatches) {
// "coveringCount" makes sure that when we have two
// or more covering indexes, we choose the one
// that covers more
cost -= coveringCount;
}
}
return cost;
}
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