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);
}
