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Jialin Qiao closed IOTDB-471. ----------------------------- Resolution: Fixed > NullPoint exception when merging all TsFiles (may caused by TimeRange > Partition) > -------------------------------------------------------------------------------- > > Key: IOTDB-471 > URL: https://issues.apache.org/jira/browse/IOTDB-471 > Project: Apache IoTDB > Issue Type: Bug > Components: Core/Engine > Reporter: Xiangdong Huang > Priority: Major > Labels: pull-request-available > Fix For: 0.10.0-SNAPSHOT > > Attachments: image-2020-02-10-20-32-03-335.png > > Time Spent: 50m > Remaining Estimate: 0h > > Hi, > In an application, there are millions of time series. In this case, when we > enable dynamic_parameter, each TsFile has only 7MB. > Therefore, there are too many TsFiles and the following query is quite slow: > SELECT longitude,latitude,altitude,'11',windDirection2min,...(other 65 > columns) FROM root.national.*.5.* WHERE time = 2020-01-18 20:00:00 group by > device > The above query returns 2400 rows and spends 8 seconds....... (Total data is > just 2GB). > So, I begin to run merge to accelerate the query speed and the following > exception occurs: > !image-2020-02-10-20-32-03-335.png|width=799,height=527! > If we check the codes, the null point exception is caused by: > > {code:java} > > private boolean updateLatestFlushTimeCallback(TsFileProcessor processor) { > // update the largest timestamp in the last flushing memtable > for (Entry<String, Long> entry : > latestTimeForEachDevice.get(processor.getTimeRangeId()) > .entrySet()) { > latestFlushedTimeForEachDevice.get(processor.getTimeRangeId()) > .put(entry.getKey(), entry.getValue()); > } > return true; > } > > {code} > > I know it is hard to reproduce, but can someone help to check and analyze the > codes? > Or, at least add more logs for helping to analyze such cases in the future. > [~SilverNarcissus] [~jt2594838] > > -- This message was sent by Atlassian Jira (v8.3.4#803005)