Tian Jiang created IOTDB-981:
--------------------------------
Summary: Give higher priority to unseq data in chunk cache
Key: IOTDB-981
URL: https://issues.apache.org/jira/browse/IOTDB-981
Project: Apache IoTDB
Issue Type: Improvement
Components: Core/Engine
Reporter: Tian Jiang
Cache unseq data chunk may provide large benefits for queries, consider the
following situation:
We have 3 seq chunks: s0, s1, and s2; and 1 unseq chunk: u0, which overlaps
with all 3 seq chunks. Assuming the 3 chunks are stored more closely (having
lowing seek costs when accessed sequentially).
If we can only cache one chunk in chunk cache, and if we choose to cache any of
the seq chunks, we then must seek between seq chunks and unseq chunks. If we
cache the unseq chunk, then only seeks between seq chunks are required, which
is clearly more efficient.
The simple example shows that giving a higher priority to unseq chunks is
beneficial, but it remains to be seen whether this conclusion can be
generalized.
Any further discussion is welcomed here.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
