Csaba Ringhofer has posted comments on this change. ( http://gerrit.cloudera.org:8080/16719 )
Change subject: IMPALA-10323: use snprintf instead of lexical_cast to cast to string ...................................................................... Patch Set 1: > (1 comment) > > > (1 comment) > > use buffer may result in lock contention in multi-thread mode where > I want to improve performance. > To save memory, I have another proposal: > May be we can define 3 level char size : 5,10,20, > for bigint value , > if value<99999999999 && value > -999999999, then change char_size > to 10; else if value <99999 && value>-9999, than change char size > to 5; > (1 comment) > > > (1 comment) > > use buffer may result in lock contention in multi-thread mode where > I want to improve performance. > To save memory, I have another proposal: > May be we can define 3 level char size : 5,10,20, > for bigint value , > if value<99999999999 && value > -999999999, then change char_size > to 10; else if value <99999 && value>-9999, than change char size > to 5; CopyFrom willl > (1 comment) > > > (1 comment) > > use buffer may result in lock contention in multi-thread mode where > I want to improve performance. > To save memory, I have another proposal: > May be we can define 3 level char size : 5,10,20, > for bigint value , > if value<99999999999 && value > -999999999, then change char_size > to 10; else if value <99999 && value>-9999, than change char size > to 5; CopyFrom allocates memory exactly the same way as the constructor of StringVal does in your current solution: https://github.com/apache/impala/blob/master/be/src/udf/udf.cc#L517 both will end up in AllocateForResults - https://github.com/apache/impala/blob/master/be/src/udf/udf.cc#L470 which uses a mempool dedicated to this thread, so it shouldn't cause any contention in multi-threaded code -- To view, visit http://gerrit.cloudera.org:8080/16719 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: Ief1d6b2c2cb5961c1d6cee1b0eac86ab61509768 Gerrit-Change-Number: 16719 Gerrit-PatchSet: 1 Gerrit-Owner: wesleydeng <[email protected]> Gerrit-Reviewer: Csaba Ringhofer <[email protected]> Gerrit-Reviewer: Gabor Kaszab <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Reviewer: abeltian <[email protected]> Gerrit-Reviewer: wesleydeng <[email protected]> Gerrit-Comment-Date: Tue, 17 Nov 2020 13:27:15 +0000 Gerrit-HasComments: No
