As you probably know CouchDB will not automatically reclaim unused space, nor compact or clean up its views during normal operation.  Instead these processes are meant to be run at optimal times (ie; off peak hours) so they do not affect user performance during critical periods.

Over time this obviously means that any CouchDB can grow to be huge unless it is tended to.

This script is designed to be run from a scheduler (like cron) and target a CouchDB instance/URL.  It first fetches all the DBs inside it (except the special _underscore ones) and then trigger a DB compaction.  For each DB all the views inside are given the cleanup (for old versions of views) and a compaction commands as well.  To my knowledge this is all of the compaction/cleanup processes CouchDB does.

Note: The script will exit fairly quickly because CouchDB will simply acknowledge the commands and then go off and process the requests (which can take some time).  Just because the script finished does not indicate that the compaction has completed.

Feel free to post questions or report problems in the comments!

Without further ado, here it is:

#!/usr/local/bin/bash

#
#  A-Team Systems CouchDB Compaction Script
#  http://www.ateamsystems.com/
#  
#  Copyright (c) 2008-2011, All Rights Reserved
#

#
# Example usage:
# ---------------------- -
#
# Reports only errors when passed no params:
# ./scriptfile 
#
# Verbosely shows what it is doing when passed 'int'
# ./scriptfile int
#



#
# Configuration
# ---------------------- -

# Change to the URL of your CouchDB
BASEURL="http://USERNAME:PASSOWRD@HOSTNAME:5984";

# Make sure sed, curl and awk are in the path
PATH="${PATH}:/usr/local/bin";

# ---------------------- -
# End Configuration
#



#
# ---- Functions
#

#
# Passes parms to echo if debugging is on, otherwise nothing
#
function DEcho
   {
   if [ "${TKDEBUGON}"x == "Yes"x ]
      then
      echo "$1" "$2" "$3" "$4" "$5" "$6" "$7" "$8" "$9";
   fi
   }

#
# Makes a CouchDB request via curl
#
function CouchReq( )
   {
   MODE="$1";
   URL="$2";

   if [ ${MODE}x == "GET"x ]
      then
      curl -s ${BASEURL}${URL};
   else
      curl -s -H "Content-Type: application/json" -X POST ${BASEURL}${URL};
   fi
   }

#
# ---- Command line params
#
if [ "${1}"x == "int"x ]
   then
   echo "--- Starting in interactive mode";
   INTERACTIVE="Yes";
   TKDEBUGON="Yes";
else
   INTERACTIVE="No";
fi


#
# ---- Main Run-time
#

# -- Get the list of DBs
DBLIST=`CouchReq "GET" "/_all_dbs" | sed -e s:"\["::g | sed -e s:"\]"::g | sed -e s:\"::g | sed -e s:,:" ":g`;

# -- Loop through 'em
for DB in ${DBLIST}
do
   if [ ${DB:0:1} != "_" ]
      then
      DEcho "${DB} - Triggering DB compaction ...";
      RESP=`CouchReq "POST" "/${DB}/_compact"`;
      if [ "${RESP}"x != '{"ok":true}'x ]
         then
         echo "${DB} - ERROR triggering compaction, CouchDB response : ${RESP}";
      else
         DEcho "${DB} - Compaction triggered.";
      fi

      DEcho "${DB} - Triggering outdated view clean up ...";
      RESP=`CouchReq "POST" "/${DB}/_view_cleanup"`;
      if [ "${RESP}"x != '{"ok":true}'x ]
         then
         echo "${DB} - ERROR triggering view clean up, CouchDB response : ${RESP}";
      else
         DEcho "${DB} - Clean up triggered.";
      fi
      
      DEcho "${DB} - Getting view list ...";
      DESIGNLIST=`CouchReq "GET" "/${DB}/_all_docs?startkey=\"_design/\"&endkey=\"_design0\"&include_docs=true" | awk -F ":" '{print $3}' | awk -F \" '{print $2}' | grep "^_design/" | sed -e s:"_design/"::g`;
      #echo "   views: ${DESIGNLIST}";

      for DESIGN in ${DESIGNLIST}
      do
         DEcho "   Compacting views in '${DESIGN}' ...";
         RESP=`CouchReq "POST" "/${DB}/_compact/${DESIGN}"`;
         if [ "${RESP}"x != '{"ok":true}'x ]
            then
            echo "      ${DESIGN} - ERROR triggering compaction, CouchDB response : ${RESP}";
         else
            DEcho "     - View compaction triggered."
         fi
      done
   fi
done