[improvement](load)disable shrink memory by default (#19714)

disable shrink memory by default, it becomes very slow when importing large amounts of data
you can turn on If you think it's necessary

be/src/common/config.cpp

@@ -993,6 +993,9 @@ DEFINE_mInt32(s3_write_buffer_size, "5242880");
 // s3_write_buffer_whole_size / s3_write_buffer_size
 DEFINE_mInt32(s3_write_buffer_whole_size, "524288000");
 
+//disable shrink memory by default
+DEFINE_Bool(enable_shrink_memory, "false");
+
 #ifdef BE_TEST
 // test s3
 DEFINE_String(test_s3_resource, "resource");

be/src/common/config.h

@@ -1008,6 +1008,9 @@ DECLARE_mInt32(s3_write_buffer_size);
 // s3_write_buffer_whole_size / s3_write_buffer_size
 DECLARE_mInt32(s3_write_buffer_whole_size);
 
+//enable shrink memory
+DECLARE_Bool(enable_shrink_memory);
+
 #ifdef BE_TEST
 // test s3
 DECLARE_String(test_s3_resource);

be/src/olap/delta_writer.cpp

@@ -225,7 +225,7 @@ Status DeltaWriter::write(const vectorized::Block* block, const std::vector<int>
     }
     _mem_table->insert(block, row_idxs, is_append);
 
-    if (UNLIKELY(_mem_table->need_agg())) {
+    if (UNLIKELY(_mem_table->need_agg() && config::enable_shrink_memory)) {
         _mem_table->shrink_memtable_by_agg();
     }
     if (UNLIKELY(_mem_table->need_flush())) {