Want to Compare values of 2 maps having billions of data in java -


i getting values database storing in maps. want compare values of 2 maps , load database problem is, maps having 100ks of data. right code written in such way comparing every entry eg if both maps having 200k of entries looping 200k * 200k times , taking days & days. need compare string , long values separately.

so there efficient way compare can avoid unnecessary looping?

here code written , old code:

below getallmaps method retrieving data database , storing in maps:

protected hashtable recordslist = new hashtable(); protected hashtable recordslistic = new hashtable();  public void getallmaps() throws exception {      int count = 0;     int = 0;     int j = 0;     int k = 0;     long nicphyport, nicid;     string ipv4val, ipv6val;     try {         trace.debug("ruuning pvc sql map");         nicpvcstmt.setfetchsize(5000);         resultset rs = nicpvcstmt.executequery();         int rcnt = 0;         while (rs.next()) {             rcnt++;             hashtable rownic = new hashtable();             nicid = rs.getlong("id");             pvcid = rs.getlong("icore_pvc_id_value");             nicphyport = rs.getlong("id_phy_port");             nicsiteid = rs.getlong("id_site_inventory_site_rep");             rownic.put("niclogport", nicid);             rownic.put("nicphyport", nicphyport);             rownic.put("nicpvc", pvcid);             rownic.put("nicsite", nicsiteid);             recordslist.put(count, rownic);             count++;         }          if (rs != null) rs.close();         geticorepvcunifiedrec.setfetchsize(5000);         rs = geticorepvcunifiedrec.executequery();         int rcnt1 = 0;         while (rs.next()) {             rcnt1++;             hashtable row = new hashtable();             icoreid = rs.getlong("id");             icorephyid = rs.getlong("id_phy_port");             pvcid = rs.getlong("icore_pvc_id_value");             row.put("icoreid", icoreid);             row.put("icphyport", icorephyid);             row.put("pvcid", pvcid);              recordslistic.put(i, row);             i++;         }          if (rs != null) rs.close();      } catch (exception ex) {         ex.getmessage();         ex.printstacktrace();     } }

below method checkpvcunificationapplies maps getting compared:

both maps recordslist , recordslistic having billions of data , because of 2nd loop taking lots of time

public void checkpvcunificationapplies(connection gcon) throws exception {     long icoreid, icorepvc, phyportid;      int cnt = 0;     try {         trace.debug("checkunificationapplies--");         (int = 0; < recordslist.size(); i++) {              hashtable tbl = (hashtable) recordslist.get(i);             //trace.debug("under check table "+tbl);             long nonicid = (long) tbl.get("niclogport");             long pvcvalue = (long) tbl.get("nicpvc");             long nicphyportid = (long) tbl.get("nicphyport");             long nicsiteid = (long) tbl.get("nicsite");             (int j = 0; j < recordslistic.size(); j++) {                 //trace.debug("list item iteration-->"+j);                 hashtable pvctbl = (hashtable) recordslistic.get(j);                 trace.debug("under pvctbl   values " + pvctbl);                 icoreid = (long) pvctbl.get("icoreid");                 icorepvc = (long) pvctbl.get("pvcid");                 phyportid = (long) pvctbl.get("icphyport");                 //icsite=(long)pvctbl.get("icphyport");                 trace.debug("matching " + pvcvalue + " " + icorepvc);                 if (pvcvalue == icorepvc) {                     icoreid = unify.geocodematchfound(nicsiteid, icoreid, gcon);                     if (icoreid > 0) {                         trace.debug("all values icoreid , nonicore " + icoreid + ":" + nonicid + " " + phyportid + nicphyportid);                         cs.setlong(1, icoreid);                         cs.setlong(2, nonicid);                         cs.setlong(3, phyportid);                         cs.setlong(4, nicphyportid);                         cs.addbatch();                         cnt++;                     }                 }                  if (cnt % 50000 == 0) {                     cs.executebatch();                     cnt = 0;                 }             }         }         if (cnt > 0) {             cs.executebatch();             trace.debug("executed batch >0" + cnt);         }         recordslist.clear();     } catch (exception e) {         e.getmessage();         e.printstacktrace();     } }

i not in java, let me know if there more efficient way compare above maps.

if have option use db procedures pl/sql, on there instead of doing in program. improve performance drastically.

if want extract data , compare in program, trade-off between speed, time , resources. if want fast performance, add more resources, , design effective algorithm fetch data in chunks compare.


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