CASSANDRA storage: cursor performance (#312)

vharseko

24.59.2023 6877de268aedfc0715bcc3578a7695c4ee278a7f

 opendj-server-legacy/src/main/java/org/opends/server/backends/cassandra/Storage.java

@@ -62,7 +62,6 @@
import com.datastax.oss.driver.api.core.cql.ResultSet;
import com.datastax.oss.driver.api.core.cql.Row;
import com.datastax.oss.driver.api.core.cql.Statement;
import com.datastax.oss.driver.api.core.servererrors.InvalidQueryException;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
@@ -311,6 +310,8 @@
      public CursorImpl(TransactionImpl tx,TreeName treeName) {
         this.treeName=treeName;
         this.tx=tx;
         rc=full();
         iterator=rc.iterator();
      }

      ResultSet full(){
@@ -322,10 +323,6 @@
      
      @Override
      public boolean next() {
         if (iterator==null) {
            rc=full();
            iterator=rc.iterator();
         }
         try {
            current=iterator.next();
            return true;
@@ -371,20 +368,17 @@
         rc=null;
      }

      ResultSet full(ByteSequence key){
         return execute(
                  prepared.getUnchecked("SELECT key,value FROM "+getTableName()+" WHERE baseDN=:baseDN and indexId=:indexId and key>=:key ORDER BY key").bind()
                     .setString("baseDN", treeName.getBaseDN()).setString("indexId", treeName.getIndexId()) 
                     .setByteBuffer("key", ByteBuffer.wrap(key.toByteArray()))
                  );
      }

      @Override
      public boolean positionToKeyOrNext(ByteSequence key) {
         rc=full(key); // start iterator from key key>=:key 
         iterator=rc.iterator();
         if (iterator.hasNext()) {
         if (!isDefined() || key.compareTo(getKey())<0) { //restart iterator
            iterator=rc.iterator();
         }
         while (iterator.hasNext()) {
            current=iterator.next();
            return true;
            if (key.compareTo(getKey())<=0) {
               return true;
            }
         }
         current=null;
         return false;
@@ -392,35 +386,37 @@
      
      @Override
      public boolean positionToKey(ByteSequence key) {
         if (positionToKeyOrNext(key) && key.equals(getKey())){
         if (!isDefined() || key.compareTo(getKey())<0) {  //restart iterator
            iterator=rc.iterator();
         }
         if (isDefined() && key.compareTo(getKey())==0) {
            return true;
         }
         while (iterator.hasNext()) {
            current=iterator.next();
            if (key.compareTo(getKey())==0) {
               return true;
            }
         }
         current=null;
         return false;
      }

      ResultSet last(){
         return execute(
                  prepared.getUnchecked("SELECT key,value FROM "+getTableName()+" WHERE baseDN=:baseDN and indexId=:indexId ORDER BY key DESC LIMIT 1").bind()
                     .setString("baseDN", treeName.getBaseDN()).setString("indexId", treeName.getIndexId()) 
                  );
      }
      
      @Override
      public boolean positionToLastKey() {
         rc=last(); 
         iterator=rc.iterator();
         if (iterator.hasNext()) {
         while (iterator.hasNext()) {
            current=iterator.next();
         }
         if (current!=null) {
            return true;
         }
         current=null;
         return false;
      }

      @Override
      public boolean positionToIndex(int index) {
         iterator=rc.iterator(); //reset position
         iterator=rc.iterator();  //restart iterator
         int ct=0;
         while(iterator.hasNext()){
            current=iterator.next();