Fixed a bug in an implementation of the query status reporting method

The older version of the method didn't return the complete info
on queries that already finished. The new code uses the final
query statistics where it's needed.

Author: iagaponenko

src/czar/Czar.cc

@@ -72,6 +72,10 @@ using namespace std;
 
 extern XrdSsiProvider* XrdSsiProviderClient;
 
+// This macro is used to convert empty strings into "0" in order to avoid
+// problems with calling std::atoi() when the string is empty.
+#define ZERO_IF_EMPTY_STR(x) ((x.empty()) ? "0" : (x))
+
 namespace {
 
 string const createAsyncResultTmpl(
@@ -548,7 +552,12 @@ void Czar::removeOldResultTables() {
 SubmitResult Czar::getQueryInfo(QueryId queryId) const {
     string const context = "Czar::" + string(__func__) + " ";
     auto sqlConn = sql::SqlConnectionFactory::make(_czarConfig->getMySqlQmetaConfig());
-    string sql = "SELECT status,messageTable,resultQuery FROM QInfo WHERE queryId=" + to_string(queryId);
+    string sql =
+            "SELECT "
+            "status,UNIX_TIMESTAMP(submitted),UNIX_TIMESTAMP(completed),chunkCount,messageTable,resultQuery "
+            "FROM QInfo WHERE "
+            "queryId=" +
+            to_string(queryId);
     sql::SqlResults results;
     sql::SqlErrorObject err;
     if (!sqlConn->runQuery(sql, results, err)) {
@@ -558,9 +567,13 @@ SubmitResult Czar::getQueryInfo(QueryId queryId) const {
         throw runtime_error(msg);
     }
     vector<string> colStatus;
+    vector<string> colSubmitted;
+    vector<string> colCompleted;
+    vector<string> colChunkCount;
     vector<string> colMessageTable;
     vector<string> colResultQuery;
-    if (!results.extractFirst3Columns(colStatus, colMessageTable, colResultQuery, err)) {
+    if (!results.extractFirst6Columns(colStatus, colSubmitted, colCompleted, colChunkCount, colMessageTable,
+                                      colResultQuery, err)) {
         string const msg = context + "Failed to extract info for the user query, err=" + err.printErrMsg() +
                            ", sql=" + sql;
         throw runtime_error(msg);
@@ -606,14 +619,18 @@ SubmitResult Czar::getQueryInfo(QueryId queryId) const {
     }
     switch (colTotalChunks.size()) {
         case 0:
-            // No stats means the query is over
+            // No stats means the query is over. Pull the final stats from the main table.
+            result.totalChunks = stoi(ZERO_IF_EMPTY_STR(colChunkCount[0]));
+            result.completedChunks = result.totalChunks;
+            result.queryBeginEpoch = stoi(ZERO_IF_EMPTY_STR(colSubmitted[0]));
+            result.lastUpdateEpoch = stoi(ZERO_IF_EMPTY_STR(colCompleted[0]));
             break;
         case 1:
             // The query might be still in progress
-            result.totalChunks = stoi(colTotalChunks[0]);
-            result.completedChunks = stoi(colCompletedChunks[0]);
-            result.queryBeginEpoch = stoi(colQueryBeginEpoch[0]);
-            result.lastUpdateEpoch = stoi(colLastUpdateEpoch[0]);
+            result.totalChunks = stoi(ZERO_IF_EMPTY_STR(colTotalChunks[0]));
+            result.completedChunks = stoi(ZERO_IF_EMPTY_STR(colCompletedChunks[0]));
+            result.queryBeginEpoch = stoi(ZERO_IF_EMPTY_STR(colQueryBeginEpoch[0]));
+            result.lastUpdateEpoch = stoi(ZERO_IF_EMPTY_STR(colLastUpdateEpoch[0]));
             break;
         default:
             // Should never be here.