[jira] [Commented] (IOTDB-1264) Insert unseq file to seq files when possible
[ https://issues.apache.org/jira/browse/IOTDB-1264?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=17311270#comment-17311270 ] Tian Jiang commented on IOTDB-1264: --- No, but it is easy to know how many times the file has been flushed before it is closed, and if it is flushed only once, this solution is appliable. > Insert unseq file to seq files when possible > > > Key: IOTDB-1264 > URL: https://issues.apache.org/jira/browse/IOTDB-1264 > Project: Apache IoTDB > Issue Type: Improvement > Components: Core/Engine >Reporter: Tian Jiang >Priority: Minor > Labels: file, unseq > > We judge if data belongs to the seq region or unseq region only by the > lastFlushedTime of each device, which makes the following situation possible: > 2 seq files and their time ranges: seq1[0, 99], seq2[300, 500] > 1 unseq file and its time range: unseq1[150, 200] > Intuitively, we can just make them 3 seq files, which may potentially reduce > query overhead. > One solution may be: right after we close one unseq file, we check if it > actually overlaps with any seq file(s), and if not, we insert it into a > proper position of the seq files instead of keeping it in unseq files. > Another merit is that this avoids the case mentioned in > https://github.com/apache/iotdb/pull/2920#pullrequestreview-623932806, > because each unseq file will definitely overlap at least one seq file. -- This message was sent by Atlassian Jira (v8.3.4#803005)
[jira] [Commented] (IOTDB-1264) Insert unseq file to seq files when possible
[ https://issues.apache.org/jira/browse/IOTDB-1264?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=17311263#comment-17311263 ] WangChao commented on IOTDB-1264: - Can a unseq file be simply put into the list of seq files? If there are overlapping chunks in unseq file, can our query handle this situation normally? > Insert unseq file to seq files when possible > > > Key: IOTDB-1264 > URL: https://issues.apache.org/jira/browse/IOTDB-1264 > Project: Apache IoTDB > Issue Type: Improvement > Components: Core/Engine >Reporter: Tian Jiang >Priority: Minor > Labels: file, unseq > > We judge if data belongs to the seq region or unseq region only by the > lastFlushedTime of each device, which makes the following situation possible: > 2 seq files and their time ranges: seq1[0, 99], seq2[300, 500] > 1 unseq file and its time range: unseq1[150, 200] > Intuitively, we can just make them 3 seq files, which may potentially reduce > query overhead. > One solution may be: right after we close one unseq file, we check if it > actually overlaps with any seq file(s), and if not, we insert it into a > proper position of the seq files instead of keeping it in unseq files. > Another merit is that this avoids the case mentioned in > https://github.com/apache/iotdb/pull/2920#pullrequestreview-623932806, > because each unseq file will definitely overlap at least one seq file. -- This message was sent by Atlassian Jira (v8.3.4#803005)
