diff --git a/packages/api/src/shell/copyStream.js b/packages/api/src/shell/copyStream.js
index 353c7369c..60e49deb7 100644
--- a/packages/api/src/shell/copyStream.js
+++ b/packages/api/src/shell/copyStream.js
@@ -2,12 +2,17 @@ const EnsureStreamHeaderStream = require('../utility/EnsureStreamHeaderStream');
 
 function copyStream(input, output) {
   return new Promise((resolve, reject) => {
-    const ensureHeader = new EnsureStreamHeaderStream();
     const finisher = output['finisher'] || output;
     finisher.on('finish', resolve);
     finisher.on('error', reject);
-    input.pipe(ensureHeader);
-    ensureHeader.pipe(output);
+
+    if (output.requireFixedStructure) {
+      const ensureHeader = new EnsureStreamHeaderStream();
+      input.pipe(ensureHeader);
+      ensureHeader.pipe(output);
+    } else {
+      input.pipe(output);
+    }
   });
 }
 
diff --git a/packages/api/src/shell/jsonArrayWriter.js b/packages/api/src/shell/jsonArrayWriter.js
index 3e631b30f..39e1831be 100644
--- a/packages/api/src/shell/jsonArrayWriter.js
+++ b/packages/api/src/shell/jsonArrayWriter.js
@@ -11,10 +11,7 @@ class StringifyStream extends stream.Transform {
     let skip = false;
 
     if (!this.wasHeader) {
-      skip =
-        chunk.__isStreamHeader ||
-        // TODO remove isArray test
-        Array.isArray(chunk.columns);
+      skip = chunk.__isStreamHeader;
       this.wasHeader = true;
     }
     if (!skip) {
diff --git a/packages/api/src/shell/jsonLinesReader.js b/packages/api/src/shell/jsonLinesReader.js
index 55c9ca110..113a9a788 100644
--- a/packages/api/src/shell/jsonLinesReader.js
+++ b/packages/api/src/shell/jsonLinesReader.js
@@ -12,14 +12,14 @@ class ParseStream extends stream.Transform {
   _transform(chunk, encoding, done) {
     const obj = JSON.parse(chunk);
     if (!this.wasHeader) {
-      if (
-        !obj.__isStreamHeader &&
-        // TODO remove isArray test
-        !Array.isArray(obj.columns)
-      ) {
-        this.push({ columns: Object.keys(obj).map(columnName => ({ columnName })) });
+      if (!obj.__isStreamHeader) {
+        this.push({
+          __isStreamHeader: true,
+          __isDynamicStructure: true,
+          // columns: Object.keys(obj).map(columnName => ({ columnName })),
+        });
       }
-      
+
       this.wasHeader = true;
     }
     if (!this.limitRows || this.rowsWritten < this.limitRows) {
diff --git a/packages/api/src/shell/jsonLinesWriter.js b/packages/api/src/shell/jsonLinesWriter.js
index 4df935fa3..495c89560 100644
--- a/packages/api/src/shell/jsonLinesWriter.js
+++ b/packages/api/src/shell/jsonLinesWriter.js
@@ -10,11 +10,7 @@ class StringifyStream extends stream.Transform {
   _transform(chunk, encoding, done) {
     let skip = false;
     if (!this.wasHeader) {
-      skip =
-        (chunk.__isStreamHeader ||
-          // TODO remove isArray test
-          Array.isArray(chunk.columns)) &&
-        !this.header;
+      skip = (chunk.__isStreamHeader && !this.header) || (chunk.__isStreamHeader && chunk.__isDynamicStructure);
       this.wasHeader = true;
     }
     if (!skip) {
diff --git a/packages/api/src/shell/sqlDataWriter.js b/packages/api/src/shell/sqlDataWriter.js
index 50324db03..56d8d567f 100644
--- a/packages/api/src/shell/sqlDataWriter.js
+++ b/packages/api/src/shell/sqlDataWriter.js
@@ -14,11 +14,7 @@ class SqlizeStream extends stream.Transform {
   _transform(chunk, encoding, done) {
     let skip = false;
     if (!this.wasHeader) {
-      if (
-        chunk.__isStreamHeader ||
-        // TODO remove isArray test
-        Array.isArray(chunk.columns)
-      ) {
+      if (chunk.__isStreamHeader) {
         skip = true;
         this.tableName = chunk.pureName;
         if (chunk.engine) {
diff --git a/packages/api/src/utility/EnsureStreamHeaderStream.js b/packages/api/src/utility/EnsureStreamHeaderStream.js
index 8a0e26651..3ffa12b58 100644
--- a/packages/api/src/utility/EnsureStreamHeaderStream.js
+++ b/packages/api/src/utility/EnsureStreamHeaderStream.js
@@ -13,11 +13,7 @@ class EnsureStreamHeaderStream extends stream.Transform {
         return;
       }
 
-      if (
-        !chunk.__isStreamHeader &&
-        // TODO remove isArray test
-        !Array.isArray(chunk.columns)
-      ) {
+      if (!chunk.__isStreamHeader) {
         this.push({
           __isStreamHeader: true,
           __isComputedStructure: true,
diff --git a/packages/tools/src/createBulkInsertStreamBase.ts b/packages/tools/src/createBulkInsertStreamBase.ts
index 068912c3d..37d0f6c5a 100644
--- a/packages/tools/src/createBulkInsertStreamBase.ts
+++ b/packages/tools/src/createBulkInsertStreamBase.ts
@@ -14,6 +14,7 @@ export function createBulkInsertStreamBase(driver, stream, pool, name, options):
   writable.buffer = [];
   writable.structure = null;
   writable.columnNames = null;
+  writable.requireFixedStructure = !driver.dialect.nosql;
 
   writable.addRow = async row => {
     if (writable.structure) {
diff --git a/plugins/dbgate-plugin-mongo/src/backend/createBulkInsertStream.js b/plugins/dbgate-plugin-mongo/src/backend/createBulkInsertStream.js
index abb1811cf..c54afbf2d 100644
--- a/plugins/dbgate-plugin-mongo/src/backend/createBulkInsertStream.js
+++ b/plugins/dbgate-plugin-mongo/src/backend/createBulkInsertStream.js
@@ -14,18 +14,13 @@ function createBulkInsertStream(driver, stream, pool, name, options) {
   writable.addRow = (row) => {
     if (!writable.wasHeader) {
       writable.wasHeader = true;
-      if (
-        row.__isStreamHeader ||
-        // TODO remove isArray test
-        Array.isArray(row.columns)
-      )
-        return;
+      if (row.__isStreamHeader) return;
     }
     if (options.createStringId) {
       row = {
         _id: new ObjectId().toString(),
         ...row,
-      }
+      };
     }
     writable.buffer.push(row);
   };