Dear Lee，
Thanks for the info about limit clause. Actually I did try to query the whole records without limit both in MySql and Doris. The situation was almost the same. Regards Thomas | | Thomas Cai 邮箱：thomas...@126.com | Signature is customized by Netease Mail Master On 04/01/2021 11:50, Lee Happen wrote: Hi Thomas Cai, I did the work to push down the limit clause for odbc table and mysql table. You can refer to this pr：https://github.com/apache/incubator-doris/pull/4707/files. If you want better performance of mapping table with limit clause, please update doris version after 0.13.15. ________________________________ From: Thomas Cai <thomas...@126.com> Sent: March 31, 2021 12:44 To: ling miao <lingm...@apache.org> Cc: dev@doris.apache.org <dev@doris.apache.org> Subject: Re:Re: The performance issue about Doris mapping table Dear Ling Miao, Thanks for your advice. Here is the result by looking for the profile. Any more suggestions? Query: Summary: Query ID: 3ef6a5a504e4466e-aeffd78390f003e6 Start Time: 2021-03-31 20:24:25 End Time: 2021-03-31 20:24:34 Total: 9s452ms Query Type: Query Query State: EOF Doris Version: 0.12.0-rc03 User: root Default Db: default_cluster:yongjin_doris Sql Statement: select projectid,projectname,uid,Cst_Proj_ID,Success_Bb_Date from yj_process_channel limit 2000 Execution Profile 3ef6a5a504e4466e-aeffd78390f003e6:(Active: 9s451ms, % non-child: 0.00%) Fragment 0: Instance 3ef6a5a504e4466e-aeffd78390f003e7 (host=TNetworkAddress(hostname:172.20.0.12, port:9060)):(Active: 9s438ms, % non-child: 0.00%) - PeakUsedReservation: 0.00 - RowsProduced: 2.0K (2000) - AverageThreadTokens: 4607182418800017400.00 - PeakReservation: 0.00 BlockMgr: - BlocksCreated: 0 - MemoryLimit: 2.00 GB - BlockWritesOutstanding: 0 - BytesWritten: 0.00 - TotalEncryptionTime: 0ns - BufferedPins: 0 - TotalReadBlockTime: 0ns - TotalBufferWaitTime: 0ns - BlocksRecycled: 0 - TotalIntegrityCheckTime: 0ns - MaxBlockSize: 8.00 MB DataBufferSender (dst_fragment_instance_id=3ef6a5a504e4466e-aeffd78390f003e7): MYSQL_SCAN_NODE (id=0):(Active: 9s437ms, % non-child: 0.00%) - NumThread: 0 - TotalRawReadTime(*): 0ns - ScanRangesComplete: 0 - RowsReturned: 2.0K (2000) - ScannerThreadsInvoluntaryContextSwitches: 0 - RowsRead: 0 - PerReadThreadRawHdfsThroughput: 0.0 /sec - ScannerThreadsVoluntaryContextSwitches: 0 - TotalReadThroughput: 0.0 /sec - ScannerThreadsTotalWallClockTime: 0ns - MaterializeTupleTime(*): 616.430us - ScannerThreadsUserTime: 0ns - ScannerThreadsSysTime: 0ns - MemoryUsed: 0.00 - BytesRead: 0.00 - RowsReturnedRate: 211 At 2021-03-31 19:43:06, "ling miao" <lingm...@apache.org> wrote: Hi Thomas Cai, Doris's mapping table read performance is indeed slightly worse than the direct read mysql table performance. But your case should not be affected. It may be that some optimizations of our later versions are not in 0.12 version. You can use this document to print out the profile of the running process. Take a look at where the entire query is slow. http://doris.apache.org/master/en/administrator-guide/running-profile.html#noun-interpretation | | Thomas Cai <thomas...@126.com> 于2021年3月31日周三 下午7:17写道： Dear All, I got a performance issue when I selected records(limit 1000) from a Doris mapping table(MySQL,records were around 150K). It took less than 2s to look for the same records from MySQL table directly, but it would take about 20s from the Doris mapping table. My Doris version is 0.12 and I tried to change several Doris configuration/variables, unfortunattely it didn't work. Did someone meet the same situation before to provide any suggestions? Whether proper configuration setting may solve the issue or have to wait JDBC for SQL in version 0.14 release. Appreciated for any feedback. Best Regards, Thomas
