These settings configure the ClickHouse server and are autogenerated from ClickHouse source.
memory_worker_correct_memory_tracker
Whether background memory worker should correct internal memory tracker based on the information from external sources like jemalloc and cgroups
memory_worker_decay_adjustment_period_ms
Duration in milliseconds that memory pressure must persist before dynamically adjusting jemalloc’s dirty_decay_ms. When memory usage remains above the purge threshold for this period, automatic dirty page decay is disabled (dirty_decay_ms=0) to aggressively reclaim memory. When usage stays below the threshold for this period, the default decay behavior is restored. Set to 0 to disable dynamic adjustment and use jemalloc’s default decay settings.
memory_worker_dynamic_hard_limit
Whether the background memory worker periodically recomputes the server’s hard memory limit at runtime as (resident memory + system available memory) * max_server_memory_usage_to_ram_ratio, so the server leaves headroom for other processes running on the same host.
When disabled, max_server_memory_usage_to_ram_ratio only caps the hard memory limit statically, at startup and on configuration reload, as in previous versions.
Has no effect when max_server_memory_usage_to_ram_ratio is 0.
memory_worker_period_ms
Tick period of background memory worker which corrects memory tracker memory usages and cleans up unused pages during higher memory usage. If set to 0, default value will be used depending on the memory usage source
memory_worker_purge_dirty_pages_threshold_ratio
The threshold ratio for jemalloc dirty pages relative to the memory available to ClickHouse server. When dirty pages size exceeds this ratio, the background memory worker forces purging of dirty pages. If set to 0, forced purging based on dirty pages ratio is disabled.
memory_worker_purge_total_memory_threshold_ratio
The threshold ratio for purging jemalloc relative to the memory available to ClickHouse server. When total memory usage exceeds this ratio, the background memory worker forces purging of dirty pages. If set to 0, forced purging based on total memory is disabled.
On each MemoryWorker tick, reserve an additional
ratio * min(resident - previous_resident, resident - tracked) on top of
the observed RSS, on the assumption that the next tick may grow by the same
amount as the last one (resident - previous_resident is the RSS growth
over the last tick). The growth is capped by resident - tracked, the part
of RSS not visible to the global memory tracker, because growth that is
already tracked is handled by the ordinary hard-limit check. The reservation
is applied to the rss counter that the global hard-limit check consults
via MemoryTracker::allocImpl, so when the extrapolated value crosses
max_server_memory_usage, subsequent allocations throw
MEMORY_LIMIT_EXCEEDED before the kernel OOM-killer fires. A value of 0
disables speculation (falling back to rss = resident); the default 1
reserves one full growth delta of headroom for the next interval. Under
sanitizers (ASan, UBSan, MSan, TSan) the default is 0, because the
resident - tracked gap is dominated by sanitizer shadow / runtime overhead
rather than tracker bookkeeping lag.
memory_worker_use_cgroup
Use current cgroup memory usage information to correct memory tracking. Last modified on July 23, 2026
