MedSplunkAggPushDownRule.java

/*******************************************************************************
   Copyright [2011] Splunk Inc

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.
********************************************************************************/

package com.splunk.udx;


import net.sf.farrago.query.FarragoJavaUdxRel;
import net.sf.farrago.trace.FarragoTrace;

import org.eigenbase.rel.*;
import org.eigenbase.relopt.*;
import org.eigenbase.relopt.hep.HepRelVertex;
import org.eigenbase.reltype.RelDataType;
import org.eigenbase.reltype.RelDataTypeField;
import org.eigenbase.rex.RexNode;

import java.io.PrintWriter;
import java.io.StringWriter;
import java.util.*;
import java.util.logging.Logger;

import static com.splunk.udx.SplunkPushDownRule.*;

/**
 *
 * @author Ledion Bitincka
 */
public class MedSplunkAggPushDownRule extends SplunkPushDownRule
{
    // luciddb -> splunk aggregate functions
    public static final Map<String, String> SUPPORTED_FUNCTIONS = new HashMap<String, String>();
    
    private static final Logger gLogger  =
        FarragoTrace.getClassTracer(MedSplunkAggPushDownRule.class);
    
    static{
        SUPPORTED_FUNCTIONS.put("min", "min"); 
        SUPPORTED_FUNCTIONS.put("max", "max"); 
        SUPPORTED_FUNCTIONS.put("sum", "sum"); 
        SUPPORTED_FUNCTIONS.put("avg", "avg"); 
        SUPPORTED_FUNCTIONS.put("count", "count"); 
        SUPPORTED_FUNCTIONS.put("first_value", "first"); 
        SUPPORTED_FUNCTIONS.put("last_value", "last"); 
        SUPPORTED_FUNCTIONS.put("stddev_samp", "stdev"); 
        SUPPORTED_FUNCTIONS.put("stddev_pop", "stdevp"); 
        SUPPORTED_FUNCTIONS.put("var_samp", "var"); 
        SUPPORTED_FUNCTIONS.put("var_pop", "varp"); 
    }
    

    // aggregate on top of udx
    public MedSplunkAggPushDownRule(MedSplunkDataServer server)
    {
        super(
            new RelOptRuleOperand(
                AggregateRel.class,
                new RelOptRuleOperand( SplunkUdxRel.class, ANY)
             ),
             "aggregate",
             server
        );
    }
    
    

  
    // implement RelOptRule
    public void onMatch(RelOptRuleCall call)
    {
        AggregateRel aggRel = (AggregateRel) call.rels[0];
        SplunkUdxRel udxRel = (SplunkUdxRel) call.rels[1];
        
        if (!isSplunkSearchUdx(udxRel)){
            return;
        }
        
        List<RelDataTypeField> fields = udxRel.getRowType().getFieldList();
        List<String> groupBy = new LinkedList<String>();
        List<String> aggFunc = new LinkedList<String>();
        
        gLogger.fine("agg str: " + aggRel.toString());
        
        for (int i = 0; i < aggRel.getGroupCount(); ++i) {
            groupBy.add(fields.get(i).getName());
            gLogger.fine("adding group by: " + fields.get(i).toString() );
        }

        
        for (AggregateCall aggCall : aggRel.getAggCallList()) 
        {
            final List<Integer> argList = aggCall.getArgList();
            String funcName = aggCall.getAggregation().getName().toLowerCase();
            String origFuncName = funcName;
            
            funcName = SUPPORTED_FUNCTIONS.get(funcName);
            gLogger.fine("translated to farrago.funcName=" + origFuncName + " to Splunk.funcName=" + funcName + ", argList.size=" + argList.size());
            
            // right now we only support single aggreate functions
            if (funcName == null || argList.size() > 1) {
                return;
            }
            
            // build aggregate function, sometimes we don't need an argument in splunk: ... | stats count BY foobar
            String funcToAdd = funcName;
            if(argList.size() > 0)
            {
                // get name of the first argument
                String argName =  fields.get(argList.get(0)).getName();
                funcToAdd      = funcName + "("  + searchEscape(argName) + ")";
            }
            aggFunc.add(funcToAdd);
            gLogger.fine("adding aggFunc: " + funcToAdd );
        }
        
        
        if(aggFunc.isEmpty())
            return;

        // the first bunch of fields are the GROUP BY fields
        RelDataType topRow = aggRel.getRowType();
        gLogger.fine("agg fieldNames: " + getFieldsString(topRow));
        
        int start = groupBy.size(), i=0;
        StringBuilder stats = new StringBuilder("| stats ");
        for(String f : aggFunc){
            if(i++>0)
                stats.append(", ");
            stats.append(f).append(" AS ").append(searchEscape(topRow.getFields()[start++].getName()));
        }
       

        if(!groupBy.isEmpty()) 
        { 
            stats.append(" BY ");
            i=0;
            for(String g : groupBy){
                if(i++>0)
                   stats.append(", ");
                 stats.append(searchEscape(g));
           }
        }

        gLogger.info("agg str: " + aggRel.toString() + " splunk agg: " + stats.toString());
        // aggregators create fields, so pass its set of fields as the bottom fields, it can also have non-null fields
        call.transformTo(appendSearchString(stats.toString(), udxRel, null, null, topRow, aggRel.getRowType(), true));
    }
}