> ## Documentation Index
> Fetch the complete documentation index at: https://clickhouse.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# merge_selector_* MergeTree table settings
> ClickHouse MergeTree table settings in the merge_selector_* generated group.
export const SettingsInfoBlock = ({type, default_value, changeable_without_restart}) => {
return
;
};
These settings are available in [system.merge\_tree\_settings](/docs/reference/system-tables/merge_tree_settings) and are autogenerated from ClickHouse source.
merge\_selector\_algorithm
The algorithm to select parts for merges assignment
merge\_selector\_base
Affects write amplification of
assigned merges (expert level setting, don't change if you don't understand
what it is doing). Works for Simple and StochasticSimple merge selectors
merge\_selector\_blurry\_base\_scale\_factor
Controls when the logic kicks in relatively to the number of parts in
partition. The bigger the factor the more belated reaction will be.
Enable heuristic for simple merge selector which will lower maximum limit for merge choice.
By doing so number of concurrent merges will increase which can help with TOO\_MANY\_PARTS
errors but at the same time this will increase the write amplification.
Enable heuristic for selecting parts for merge which removes parts from right
side of range, if their size is less than specified ratio (0.01) of sum\_size.
Works for Simple and StochasticSimple merge selectors
Controls the exponent value used in formulae building lowering curve. Lowering exponent will
lower merge widths which will trigger increase in write amplification. The reverse is also true.