recollq: add option to obtain exact result count

src/rcldb/rclquery.cpp

@@ -169,15 +169,12 @@ void Query::setSortBy(const string& fld, bool ascending) {
             (m_sortAscending ? "ascending" : "descending") << "\n");
 }
 
-//#define ISNULL(X) (X).isNull()
-#define ISNULL(X) !(X)
-
 // Prepare query out of user search data
 bool Query::setQuery(std::shared_ptr<SearchData> sdata)
 {
     LOGDEB("Query::setQuery:\n");
 
-    if (!m_db || ISNULL(m_nq)) {
+    if (!m_db || !m_nq) {
         LOGERR("Query::setQuery: not initialised!\n");
         return false;
     }
@@ -247,7 +244,7 @@ bool Query::setQuery(std::shared_ptr<SearchData> sdata)
 
 bool Query::getQueryTerms(vector<string>& terms)
 {
-    if (ISNULL(m_nq))
+    if (!m_nq)
         return false;
 
     terms.clear();
@@ -336,30 +333,37 @@ static const int qquantum = 50;
 
 // Get estimated result count for query. Xapian actually does most of
 // the search job in there, this can be long
-int Query::getResCnt()
+int Query::getResCnt(int checkatleast, bool useestimate)
 {
-    if (ISNULL(m_nq) || !m_nq->xenquire) {
+    if (!m_db || !m_nq || !m_nq->xenquire) {
         LOGERR("Query::getResCnt: no query opened\n");
         return -1;
     }
+    LOGDEB0("Query::getResCnt: checkatleast " << checkatleast << " estimate " <<
+            useestimate << "\n");
+
     if (m_resCnt >= 0)
         return m_resCnt;
 
-    m_resCnt = -1;
     if (m_nq->xmset.size() <= 0) {
         Chrono chron;
-
-        XAPTRY(m_nq->xmset = 
-               m_nq->xenquire->get_mset(0, qquantum, 1000);
-               m_resCnt = m_nq->xmset.get_matches_lower_bound(),
+        XAPTRY(if (checkatleast == -1)
+                   checkatleast = m_db->docCnt();
+               m_nq->xmset = m_nq->xenquire->get_mset(0, qquantum, checkatleast),
                m_db->m_ndb->xrdb, m_reason);
-
-        LOGDEB("Query::getResCnt: "<<m_resCnt<<" "<< chron.millis() << " mS\n");
-        if (!m_reason.empty())
+        if (!m_reason.empty()) {
             LOGERR("xenquire->get_mset: exception: " << m_reason << "\n");
+            return -1;
+        }
+        LOGDEB("Query::getResCnt: get_mset: " << chron.millis() << " mS\n");
+    }
+
+    if (useestimate) {
+        m_resCnt = m_nq->xmset.get_matches_estimated();
     } else {
         m_resCnt = m_nq->xmset.get_matches_lower_bound();
     }
+    LOGDEB("Query::getResCnt: " << m_resCnt << "\n");
     return m_resCnt;
 }
 
@@ -374,7 +378,7 @@ int Query::getResCnt()
 bool Query::getDoc(int xapi, Doc &doc, bool fetchtext)
 {
     LOGDEB1("Query::getDoc: xapian enquire index " << xapi << "\n");
-    if (ISNULL(m_nq) || !m_nq->xenquire) {
+    if (!m_nq || !m_nq->xenquire) {
         LOGERR("Query::getDoc: no query opened\n");
         return false;
     }
@@ -457,7 +461,7 @@ vector<string> Query::expand(const Doc &doc)
 {
     LOGDEB("Rcl::Query::expand()\n");
     vector<string> res;
-    if (ISNULL(m_nq) || !m_nq->xenquire) {
+    if (!m_nq || !m_nq->xenquire) {
         LOGERR("Query::expand: no query opened\n");
         return res;
     }

src/rcldb/rclquery.h

@@ -90,8 +90,15 @@ public:
      */
     bool setQuery(std::shared_ptr<SearchData> q);
 
-    /** Get results count for current query */
-    int getResCnt();
+
+    /**  Get results count for current query.
+     *
+     * @param useestimate Use get_matches_estimated() if true, else 
+     *     get_matches_lower_bound()
+     * @param checkatleast checkatleast parameter to get_mset(). Use -1 for 
+     *     full scan.
+     */
+    int getResCnt(int checkatleast=1000, bool useestimate=false);
 
     /** Get document at rank i in current query results. */
     bool getDoc(int i, Doc &doc, bool fetchtext = false);