diff --git a/lib/handlers/prom_query.js b/lib/handlers/prom_query.js
index 7a28410d..59935bef 100644
--- a/lib/handlers/prom_query.js
+++ b/lib/handlers/prom_query.js
@@ -39,7 +39,7 @@ async function handler (req, res) {
       }).send(response)
   } catch (err) {
     asyncLogError(err, req.log)
-    return res.send(empty)
+    return res.code(500).send(JSON.stringify({ status: 'error', error: err.message }))
   }
 }
 
diff --git a/lib/handlers/prom_query_range.js b/lib/handlers/prom_query_range.js
index 74a1a105..9452224c 100644
--- a/lib/handlers/prom_query_range.js
+++ b/lib/handlers/prom_query_range.js
@@ -17,9 +17,13 @@ async function handler (req, res) {
   const endMs = parseInt(req.query.end) * 1000 || Date.now()
   const stepMs = parseInt(req.query.step) * 1000 || 15000
   const query = req.query.query
-  const result = await rangeQuery(query, startMs, endMs, stepMs)
-  console.log(JSON.stringify(result))
-  return res.code(200).send(result)
+  try {
+    const result = await rangeQuery(query, startMs, endMs, stepMs)
+    console.log(JSON.stringify(result))
+    return res.code(200).send(result)
+  } catch (err) {
+    return res.code(500).send(JSON.stringify({ status: 'error', error: err.message }))
+  }
 }
 
 module.exports = handler
diff --git a/lib/handlers/prom_series.js b/lib/handlers/prom_series.js
index c581fa30..d6862b7d 100644
--- a/lib/handlers/prom_series.js
+++ b/lib/handlers/prom_series.js
@@ -20,18 +20,22 @@ async function handler (req, res) {
   const startMs = req.query.start ? parseInt(req.query.start) * 1000 : Date.now() - 7 * 24 * 3600 * 1000
   const endMs = req.query.end ? parseInt(req.query.end) * 1000 : Date.now() - 7 * 24 * 3600 * 1000
   const result = []
-  query = query.map(async (m) => {
-    const _result = await series(m, startMs, endMs)
-    result.push.apply(result, _result)
-  })
-  await Promise.all(query)
-  return res.code(200).headers({
-    'Content-Type': 'application/json',
-    'Access-Control-Allow-Origin': CORS
-  }).send(JSON.stringify({
-    status: 'success',
-    data: result
-  }))
+  try {
+    query = query.map(async (m) => {
+      const _result = await series(m, startMs, endMs)
+      result.push.apply(result, _result)
+    })
+    await Promise.all(query)
+    return res.code(200).headers({
+      'Content-Type': 'application/json',
+      'Access-Control-Allow-Origin': CORS
+    }).send(JSON.stringify({
+      status: 'success',
+      data: result
+    }))
+  } catch (err) {
+    return res.code(500).send(JSON.stringify({ status: 'error', error: err.message }))
+  }
 }
 
 module.exports = handler
diff --git a/promql/index.js b/promql/index.js
index f9fc89fd..1d9cf8aa 100644
--- a/promql/index.js
+++ b/promql/index.js
@@ -4,6 +4,10 @@ const { rawRequest } = require('../lib/db/clickhouse')
 const { DATABASE_NAME } = require('../lib/utils')
 const { clusterName } = require('../common')
 const _dist = clusterName ? '_dist' : ''
+
+class PSQLError extends Error {}
+module.exports.PSQLError = PSQLError
+
 /**
  *
  * @param query {string}
@@ -12,35 +16,56 @@ const _dist = clusterName ? '_dist' : ''
  * @param stepMs {number}
  */
 module.exports.rangeQuery = async (query, startMs, endMs, stepMs) => {
-  const resp = await prometheus.pqlRangeQuery(query, startMs, endMs, stepMs, module.exports.getData)
-  return JSON.parse(resp)
+  try {
+    const resp = await prometheus.pqlRangeQuery(query, startMs, endMs, stepMs, module.exports.getData)
+    return JSON.parse(resp)
+  } catch (e) {
+    if (e instanceof prometheus.WasmError) {
+      throw new PSQLError(e.message)
+    }
+    throw e
+  }
 }
 
 module.exports.instantQuery = async (query, timeMs) => {
-  const resp = await prometheus.pqlInstantQuery(query, timeMs, module.exports.getData)
-  return JSON.parse(resp)
+  try {
+    const resp = await prometheus.pqlInstantQuery(query, timeMs, module.exports.getData)
+    return JSON.parse(resp)
+  } catch (e) {
+    if (e instanceof prometheus.WasmError) {
+      throw new PSQLError(e.message)
+    }
+    throw e
+  }
 }
 
 module.exports.series = async (query, fromMs, toMs) => {
-  const fromS = Math.floor(fromMs / 1000)
-  const toS = Math.floor(toMs / 1000)
-  const matchers = prometheus.pqlMatchers(query)
-  const conds = getMatchersIdxCond(matchers[0])
-  const idx = getIdxSubquery(conds, fromMs, toMs)
-  const withIdx = new Sql.With('idx', idx, !!clusterName)
-  const req = (new Sql.Select())
-    .with(withIdx)
-    .select([new Sql.Raw('any(labels)'), 'labels'])
-    .from(`time_series${_dist}`)
-    .where(Sql.And(
-      Sql.Gte('date', new Sql.Raw(`toDate(fromUnixTimestamp(${fromS}))`)),
-      Sql.Lte('date', new Sql.Raw(`toDate(fromUnixTimestamp(${toS}))`)),
-      new Sql.In('fingerprint', 'in', new Sql.WithReference(withIdx))))
-    .groupBy(new Sql.Raw('fingerprint'))
-  const data = await rawRequest(req.toString() + ' FORMAT JSON',
-    null,
-    DATABASE_NAME())
-  return data.data.data.map(l => JSON.parse(l.labels))
+  try {
+    const fromS = Math.floor(fromMs / 1000)
+    const toS = Math.floor(toMs / 1000)
+    const matchers = prometheus.pqlMatchers(query)
+    const conds = getMatchersIdxCond(matchers[0])
+    const idx = getIdxSubquery(conds, fromMs, toMs)
+    const withIdx = new Sql.With('idx', idx, !!clusterName)
+    const req = (new Sql.Select())
+      .with(withIdx)
+      .select([new Sql.Raw('any(labels)'), 'labels'])
+      .from(`time_series${_dist}`)
+      .where(Sql.And(
+        Sql.Gte('date', new Sql.Raw(`toDate(fromUnixTimestamp(${fromS}))`)),
+        Sql.Lte('date', new Sql.Raw(`toDate(fromUnixTimestamp(${toS}))`)),
+        new Sql.In('fingerprint', 'in', new Sql.WithReference(withIdx))))
+      .groupBy(new Sql.Raw('fingerprint'))
+    const data = await rawRequest(req.toString() + ' FORMAT JSON',
+      null,
+      DATABASE_NAME())
+    return data.data.data.map(l => JSON.parse(l.labels))
+  } catch (e) {
+    if (e instanceof prometheus.WasmError) {
+      throw new PSQLError(e.message)
+    }
+    throw e
+  }
 }
 
 /**
diff --git a/wasm_parts/main.go b/wasm_parts/main.go
index 6d9c3fa7..a32e2ed7 100644
--- a/wasm_parts/main.go
+++ b/wasm_parts/main.go
@@ -150,7 +150,8 @@ func wrapError(err error) []byte {
 }
 
 func wrapErrorStr(err error) string {
-	return fmt.Sprintf(`{"status":"error", "error":%s}`, strconv.Quote(err.Error()))
+	//return fmt.Sprintf(`{"status":"error", "error":%s}`, strconv.Quote(err.Error()))
+	return err.Error()
 }
 
 func pql(c *ctx, query func() (promql.Query, error)) uint32 {
diff --git a/wasm_parts/main.js b/wasm_parts/main.js
index dc10abb3..a0d400de 100644
--- a/wasm_parts/main.js
+++ b/wasm_parts/main.js
@@ -4,6 +4,9 @@ const WASM_URL = join(__dirname, 'main.wasm.gz')
 const fs = require('fs')
 const { gunzipSync } = require('zlib')
 
+class WasmError extends Error {}
+module.exports.WasmError = WasmError
+
 let counter = 0
 var go
 var wasm
@@ -66,7 +69,7 @@ module.exports.pqlMatchers = (query) => {
       ctx.write(query)
       const res1 = _wasm.exports.pqlSeries(id)
       if (res1 !== 0) {
-        throw new Error('pql failed: ', ctx.read())
+        throw new WasmError(ctx.read())
       }
       /** @type {[[[string]]]} */
       const matchersObj = JSON.parse(ctx.read())
@@ -93,7 +96,7 @@ const pql = async (query, wasmCall, getData) => {
     ctx.write(query)
     const res1 = wasmCall(ctx)
     if (res1 !== 0) {
-      throw new Error('pql failed: ', ctx.read())
+      throw new WasmError(ctx.read())
     }
 
     const matchersObj = JSON.parse(ctx.read())
diff --git a/wasm_parts/main.wasm.gz b/wasm_parts/main.wasm.gz
index 86f4f5cb..18058847 100644
Binary files a/wasm_parts/main.wasm.gz and b/wasm_parts/main.wasm.gz differ