Stat digests, such as TDigest, can be expensive to merge. It is faster to buffer writes and merge them in larger chunks. DigestBuilder buffers writes to improve performance.
Declared in <folly/stats/DigestBuilder.h>
template<typename DigestT>
class DigestBuilder;Values are stored in a cpu local buffer. Hot stats will merge the cpu local buffer into a cpu-local digest when the buffer size is reached.
All methods in this class are thread safe, but it probably doesn't make sense for multiple threads to call build simultaneously. A typical usage is to buffer writes for a period of time, and then have one thread call build to merge the buffer into some other DigestT instance.
| Name | Description |
|---|---|
DigestBuilder [constructor] | Constructs a builder with the given buffer and digest sizes. |
append | Adds a value to the buffer. |
build | Builds a DigestT from the buffer. All values used to build the DigestT are removed from the buffer. |