设置完全禁用bloom filter的参数

[chejinge]

Which PikiwiDB functionalities are relevant/related to the feature request?

No response

Description

禁用也非常简单，设置为nullptr就行。 //table_ops.filter_policy.reset(rocksdb::NewBloomFilterPolicy(10, true)); table_ops.filter_policy = nullptr;

Proposed solution

optimize_filters_for_hits=true ，这个吧，设为true就不缓存最后一层。有的设置是只对新生成的sst生效，table_ops.filter_policy = nullptr;是即使已存在sst即使有bloom filter，也不会加载进内存

Alternatives considered

table_options.filter_policy.reset(rocksdb::NewBloomFilterPolicy(0));

这样的话，新的sst没有bloom filter，老的sst的bloom filter还会加载进内存

因为大部分的业务，都是查的已经存在的key，这样的话bloom filter是没啥用的，只会占内存。可以用./sst_dump --file=./strings --show_properties 看看bloom filter和index的大小

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Title: Set the parameters to completely disable bloom filter