Memory Consumption Comparison of MySQL 8.0 vs MySQL 5.7 on Small Cloud Instances

Although MySQL is often run on large‑scale systems, it is also deployed on minimal cloud instances or local laptops, where memory consumption becomes critical.

When comparing MySQL 8.0 with MySQL 5.7, the newer version uses noticeably more memory even under the same lightweight workload on a 1 GB virtual machine.

MySQL 5.7 vmstat output:

procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 4  0  65280  71608  58352 245108    0    0  2582  3611 1798 8918 18  9 11 33 30
 4  0  65280  68288  58500 247512    0    0  2094  2662 1769 8508 19  9 13 30 29
 3  1  65280  67780  58636 249656    0    0  2562  3924 1883 9323 20  9  7 37 27
 4  1  65280  66196  58720 251072    0    0  1936  3949 1587 7731 15  7 11 36 31

MySQL 8.0 vmstat output:

procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 9  1 275356  62280  60832 204736    0    0  2197  5245 2638 13453 24 13  2 34 27
 3  0 275356  60548  60996 206340    0    0  1031  3449 2446 12895 25 11 10 28 26
 7  1 275356  78188  59564 190632    0    1  2448  5082 2677 13661 26 13  6 30 25
 4  1 275356  76516  59708 192096    0    0  2247  3750 2401 12210 22 12  4 38 24

The results show MySQL 8.0 using roughly 200 MB of swap space and allocating more memory overall while using less system cache.

Top‑command screenshots (images) also illustrate that MySQL 8.0 has higher resident (RSS) and virtual (VSZ) memory, with the virtual memory far exceeding the 1 GB physical limit of the VM.

Even though neither version swaps under low load, using swap may become necessary when multiple connections or additional applications share the same VM, otherwise an out‑of‑memory (OOM) condition could occur.

Test configuration (my.cnf):

[mysqld]
innodb_buffer_pool_size=256M
innodb_buffer_pool_instances=1
innodb_log_file_size=1G
innodb_flush_method=O_DIRECT
innodb_numa_interleave=1
innodb_flush_neighbors=0
log_bin
server_id=1
expire_logs_days=1
log_output=file
slow_query_log=ON
long_query_time=0
log_slow_rate_limit=1
log_slow_rate_type=query
log_slow_verbosity=full
log_slow_admin_statements=ON
log_slow_slave_statements=ON
slow_query_log_always_write_time=1
slow_query_log_use_global_control=all
innodb_monitor_enable=all
userstat=1

Conclusion: When migrating development environments to MySQL 8.0, be aware that the same configuration consumes more memory than MySQL 5.7, so plan resources accordingly.