Vihang Karajgaonkar has posted comments on this change. ( http://gerrit.cloudera.org:8080/14319 )
Change subject: IMPALA-8984: Fix race condition in creating Kudu table ...................................................................... Patch Set 13: > > (1 comment) > > This bug happened when submit several 'create if not exists' > queries concurrently to create kudu managed table(these queries are > same, at lease same table name, without Kudu-HMS Integration). If > one query obtain 'metastoreDdlLock_', this means already create > table in kudu storage(KuduCatalogOpExecutor.createManagedTable), > then other query prepare to create table in kudu storage, but > already exists, thus throw an exception , and this caused table > droped in kudu storage which created by first query. And then the > first query continue create table in hms which already obtain > 'metastoreDdlLock_', and to the end. These queries all execute > successful, but table only exist in hms, not in kudu storage. > This bug is hard to reprodue due to relying on threads execute > path, so I mock this situation in a test case: First create a kudu > managed table, then deleted it from catalog, still reserved in > metastore. Then submit the same ddl request again, and the original > code would lead to table been deleted in kudu storage, and thus we > would got an incompleted table when invalidated table. But with > this patch fixed, we would got an normal kudu table. Thanks for the explanation. I now understand this race condition better. -- To view, visit http://gerrit.cloudera.org:8080/14319 To unsubscribe, visit http://gerrit.cloudera.org:8080/settings Gerrit-Project: Impala-ASF Gerrit-Branch: master Gerrit-MessageType: comment Gerrit-Change-Id: I1a4047bcdaa6b346765b96e8c36bb747a2b0091d Gerrit-Change-Number: 14319 Gerrit-PatchSet: 13 Gerrit-Owner: wangsheng <[email protected]> Gerrit-Reviewer: Impala Public Jenkins <[email protected]> Gerrit-Reviewer: Quanlong Huang <[email protected]> Gerrit-Reviewer: Tim Armstrong <[email protected]> Gerrit-Reviewer: Vihang Karajgaonkar <[email protected]> Gerrit-Reviewer: wangsheng <[email protected]> Gerrit-Comment-Date: Thu, 12 Dec 2019 18:41:49 +0000 Gerrit-HasComments: No
