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https://issues.apache.org/jira/browse/IMPALA-7961?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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bharath v updated IMPALA-7961:
------------------------------
Affects Version/s: Impala 2.12.0
Impala 3.1.0
> Concurrent catalog heavy workloads can cause queries with SYNC_DDL to fail
> fast
> -------------------------------------------------------------------------------
>
> Key: IMPALA-7961
> URL: https://issues.apache.org/jira/browse/IMPALA-7961
> Project: IMPALA
> Issue Type: Bug
> Components: Catalog
> Affects Versions: Impala 2.12.0, Impala 3.1.0
> Reporter: bharath v
> Priority: Critical
>
> When catalog server is under heavy load with concurrent updates to objects,
> queries with SYNC_DDL can fail with the following message.
> *User facing error message:*
> {noformat}
> ERROR: CatalogException: Couldn't retrieve the catalog topic version for the
> SYNC_DDL operation after 3 attempts.The operation has been successfully
> executed but its effects may have not been broadcast to all the coordinators.
> {noformat}
> *Exception from the catalog server log:*
> {noformat}
> I1031 00:00:49.168761 1127039 CatalogServiceCatalog.java:1903] Operation
> using SYNC_DDL is waiting for catalog topic version: 236535. Time to identify
> topic version (msec): 1088
> I1031 00:00:49.168824 1125528 CatalogServiceCatalog.java:1903] Operation
> using SYNC_DDL is waiting for catalog topic version: 236535. Time to identify
> topic version (msec): 12625
> I1031 00:00:49.168851 1131986 jni-util.cc:230]
> org.apache.impala.catalog.CatalogException: Couldn't retrieve the catalog
> topic version for the SYNC_DDL operation after 3 attempts.The operation has
> been successfully executed but its effects may have not been broadcast to all
> the coordinators.
> at
> org.apache.impala.catalog.CatalogServiceCatalog.waitForSyncDdlVersion(CatalogServiceCatalog.java:1891)
> at
> org.apache.impala.service.CatalogOpExecutor.execDdlRequest(CatalogOpExecutor.java:336)
> at org.apache.impala.service.JniCatalog.execDdl(JniCatalog.java:146)
> ::::
> {noformat}
> *What this means*
> This means that the Catalog operation is actually successful (the change has
> been committed to HMS and Catalog server cache) but the Catalog server
> noticed that it is taking longer than expected time for it to broadcast the
> changes (for whatever reason) and instead of hanging in there, it fails fast.
> The coordinators are expected to eventually sync up in the background.
> *Problem*
> - This violates the contract of the SYNC_DDL query option since the query
> returns early.
> - This is a behavioral regression from pre IMPALA-5058 state where the
> queries would wait forever for SYNC_DDL based changes to propagate.
> *Notes*
> - Usual suspect here is heavily concurrent catalog operations with long
> running DDLs.
> - Introduced by IMPALA-5058
> - My understanding is that this also applies to the Catalog V2 (or
> LocalCatalog mode) since we still rely on the CatalogServer for DDL
> orchestration and hence it takes this codepath.
> Please refer to the jira comment for technical explanation as to why this is
> happening.
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