diff --git a/lib/taskdeletedup.js b/lib/taskdeletedup.js
index 6f3cf92..9162f4d 100644
--- a/lib/taskdeletedup.js
+++ b/lib/taskdeletedup.js
@@ -1,50 +1,67 @@
 module.exports = client => {
     const constant = require('./constant'),
         schedule = require('node-schedule'),
+        { pick } = require('stream-json/filters/Pick'),
+        { parser } = require('stream-json'),
+        { streamArray } = require('stream-json/streamers/StreamArray'),
+        { chain } = require('stream-chain'),
         size = 500,
         deleteDup = async () => {
-            const count = { deleted: 0, total: 0 }
-            let lastsort = undefined, result = undefined, last = undefined
-            do {
-                result = await client.search({
-                    index: constant.index,
-                    size: size,
-                    body: {
-                        query: {
-                            match_all: {}
+            const count = { deleted: 0, total: 0, current: 0 }
+            let lastsort = undefined, last = undefined
+            await searchDup(count, lastsort, last)
+        },
+        searchDup = async (count, lastsort, last) => {
+            count.current = 0
+            const result = await client.search({
+                index: constant.index,
+                size: size,
+                body: {
+                    query: {
+                        match_all: {}
+                    },
+                    sort: [{
+                        "instance": {
+                            "order": "asc"
                         },
-                        sort: [{
-                            "instance": {
-                                "order": "asc"
-                            },
-                            "last": {
-                                "order": "desc",
-                                "numeric_type": "date_nanos",
-                                "format": "strict_date_optional_time_nanos"
-                            }
-                        }],
-                        search_after: lastsort
-                    }
-                })
-                for (const instance of result.hits.hits) {
-                    if (last && instance._source && last.instance === instance._source.instance) {
-                        await client.delete({ index: constant.index, id: instance._id })
-                        count.deleted++
-                        console.log('deleted ' + instance._id + ': ' + instance._source.instance)
-                    }
-                    else {
-                        last = instance._source
-                    }
-                    if (instance._id === result.hits.hits[result.hits.hits.length - 1]._id) {
-                        lastsort = instance.sort
-                    }
+                        "last": {
+                            "order": "desc",
+                            "numeric_type": "date_nanos",
+                            "format": "strict_date_optional_time_nanos"
+                        }
+                    }],
+                    search_after: lastsort
                 }
-                count.total += result.hits.hits.length
-                if (result.hits.hits.length !== size) {
-                    break
+            }, { asStream: true, meta: false }),
+                pipeline = chain([
+                    parser(),
+                    pick({ filter: 'hits.hits' }),
+                    streamArray(),
+                    data => data.value
+                ])
+            pipeline.on('data', async data => {
+                count.current++
+                if (last && last.instance === data._source.instance) {
+                    await client.delete({ index: constant.index, id: data._id })
+                    count.deleted++
+                    console.log('deleted ' + data._id + ': ' + data._source.instance)
                 }
-            } while (result.hits && result.hits.hits && result.hits.hits.length > 0)
-            console.log('Index: ' + constant.index + ' - Total: ' + count.total + ' - Deleted: ' + count.deleted)
+                else {
+                    last = data._source
+                }
+                if (count.current === size) {
+                    lastsort = data.sort
+                }
+            })
+            pipeline.on('end', async () => {
+                count.total += size
+                if (count.current === size) {
+                    await searchDup(count, lastsort, last)
+                } else {
+                    console.log('Index: ' + constant.index + ' - Total: ' + count.total + ' - Deleted: ' + count.deleted)
+                }
+            })
+            result.pipe(pipeline)
         },
         job = schedule.scheduleJob('0 ' + constant.taskdeletedup + ' * * *', async () => {
             await deleteDup()