diff --git a/lib/mbtiles.js b/lib/mbtiles.js
index a7388b8..8491ede 100644
--- a/lib/mbtiles.js
+++ b/lib/mbtiles.js
@@ -9,6 +9,7 @@ var sm = new (require('sphericalmercator'));
 var sqlite3 = require('sqlite3');
 var tiletype = require('tiletype');
 var ZXYStream = require('./zxystream');
+var queue = require('d3-queue').queue;
 
 function noop(err) {
     if (err) throw err;
@@ -625,34 +626,42 @@ MBTiles.prototype.geocoderDataIterator = function(type) {
     var doneSentinel = {};
     var _this = this;
 
+    var zlibQueue = queue(1);
+    var inflate = function(data, callback) {
+        zlibQueue.defer(function(cb) {
+            zlib.inflate(data, function(err, buf) {
+                callback(err, buf);
+                cb();
+            });
+        });
+    }
+
     var sending = false;
     var sendIfAvailable = function() {
         if (sending) return;
         sending = true;
 
         while (nextQueue.length && dataQueue.length) {
-            var nextCb = nextQueue.shift(), data, cbValue;
+            var nextCb = nextQueue.shift(), data;
             if (dataQueue[0] == doneSentinel) {
-                cbValue = {
-                    err: null,
-                    row: {value: undefined, done: true}
-                }
+                (function(nextCb) {
+                    setImmediate(function() {
+                        nextCb(null, {value: undefined, done: true});
+                    });
+                })(nextCb);
             } else {
                 data = dataQueue.shift();
                 maybeRefillBuffer();
 
-                cbValue = {
-                    err: data.err,
-                    row: {value: {shard: data.row.shard, data: zlib.inflateSync(data.row.data)}, done: false}
-                };
+                (function(nextCb, cbValue) {
+                    inflate(data.row.data, function(err, buf) {
+                        nextCb(
+                            data.err,
+                            {value: {shard: data.row.shard, data: buf}, done: false}
+                        );
+                    })
+                })(nextCb, data);
             }
-            // bind the callback and data now so that they don't change before the setImmediate
-            // callback is executed
-            (function(nextCb, cbValue) {
-                setImmediate(function() {
-                    nextCb(cbValue.err, cbValue.row);
-                });
-            })(nextCb, cbValue);
         }
 
         sending = false;
diff --git a/package.json b/package.json
index 56af353..6d66b74 100644
--- a/package.json
+++ b/package.json
@@ -26,6 +26,7 @@
     "Konstantin Käfer <kkaefer>"
   ],
   "dependencies": {
+    "d3-queue": "~2.0.3",
     "tiletype": "0.1.x",
     "sqlite3": "3.x",
     "sphericalmercator": "~1.0.1"
diff --git a/test/geocoder.test.js b/test/geocoder.test.js
index 49cecca..8ee064f 100644
--- a/test/geocoder.test.js
+++ b/test/geocoder.test.js
@@ -2,6 +2,8 @@ var fs = require('fs');
 var util = require('util');
 var MBTiles = require('..');
 var tape = require('tape');
+var queue = require('d3-queue').queue;
+var crypto = require('crypto');
 
 var expected = {
     bounds: '-141.005548666451,41.6690855919108,-52.615930948992,83.1161164353916',
@@ -62,15 +64,12 @@ tape('putGeocoderData', function(assert) {
         assert.ifError(err);
         to.putGeocoderData('term', 0, new Buffer('asdf'), function(err) {
             assert.ifError(err);
-            to.putGeocoderData('term', 1, new Buffer('ZZZZZ'), function(err) {
+            to.stopWriting(function(err) {
                 assert.ifError(err);
-                to.stopWriting(function(err) {
+                to.getGeocoderData('term', 0, function(err, buffer) {
                     assert.ifError(err);
-                    to.getGeocoderData('term', 0, function(err, buffer) {
-                        assert.ifError(err);
-                        assert.deepEqual('asdf', buffer.toString());
-                        assert.end();
-                    });
+                    assert.deepEqual('asdf', buffer.toString());
+                    assert.end();
                 });
             });
         });
@@ -78,26 +77,50 @@ tape('putGeocoderData', function(assert) {
 });
 
 tape('geocoderDataIterator', function(assert) {
-    var it = to.geocoderDataIterator("term");
-    var data = [];
-    var n = function(err, item) {
+    to.startWriting(function(err) {
         assert.ifError(err);
-        if (item.done) {
-            assert.equal(data.length, 2, "iterator produces two shards");
+        // get a bunch of shards of different sizes and put them in in an arbitrary order
+        var shardIds = {};
+        var q = queue()
+        while (true) {
+            var id = Math.floor(Math.random() * Math.pow(2, 16));
+            if (shardIds[id]) continue;
 
-            assert.equal(data[0].shard, 0);
-            assert.equal(data[0].data.toString(), "asdf");
+            shardIds[id] = 1;
+            q.defer(function(id, cb) {
+                to.putGeocoderData("term", id, crypto.randomBytes(Math.floor(Math.random()* 1024 * 1024)), cb);
+            }, id);
 
-            assert.equal(data[1].shard, 1);
-            assert.equal(data[1].data.toString(), "ZZZZZ");
-
-            assert.end();
-        } else {
-            data.push(item.value);
-            it.asyncNext(n);
+            if (Object.keys(shardIds).length >= 50) break;
         }
-    }
-    it.asyncNext(n);
+        q.awaitAll(function() {
+            to.stopWriting(function(err) {
+                var it = to.geocoderDataIterator("term");
+                var data = [];
+                var n = function(err, item) {
+                    assert.ifError(err);
+                    if (item.done) {
+                        assert.equal(data.length, 51, "iterator produces 51 shards");
+
+                        assert.equal(data[0].shard, 0);
+                        assert.equal(data[0].data.toString(), "asdf", "first shard data is preserved");
+
+                        var sorted = true;
+                        for (var i = 1; i < data.length; i++) {
+                            if (data[i - 1].shard >= data[i].shard) sorted = false;
+                        }
+                        assert.equal(sorted, true, "shards come back in order");
+
+                        assert.end();
+                    } else {
+                        data.push(item.value);
+                        it.asyncNext(n);
+                    }
+                }
+                it.asyncNext(n);
+            });
+        })
+    });
 })
 
 tape('getIndexableDocs', function(assert) {