Enable AO/AOCO insert to multiple files even enable_parallel is off #83
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Since commit 5acbf4e, when enable_parallel is off, we will insert into only one AO segfile even gp_appendonly_insert_files is > 1. It will make data skew after user set enable_parallel to off, while there are a lot of data inserted later or there are online-steaming ETL severs. And that make our parallel plan has a bottleneck. In general, we should try to make AO segfiles as much as GUC gp_appendonly_insert_files and avoid data skew for users, no matter users use parallel query or not. And only keep gp_appendonly_insert_files default value to 4 is enough. Remove enable_parallel when initing AO/AOCS insertDesc. Authored-by: Zhang Mingli [email protected]
Utility mode should always use segfile 0 for AO/AOCS tables. Insert multiple files in Utility mode will cause isolation2 fail when there are concurrent insertion like 0U to launch processes. Authored-by: Zhang Mingli [email protected]
We have changed gp_appendonly_insert_files to 4 by default. It will cause lots of cases fail in cases related to AO/AOCS segfile and etc. As we enable insert multiple files regardless of enable_parallel, the problems come up. Use gpconfig to set GUCs before test cases to disable insert multiple files and etc. Authored-by: Zhang Mingli [email protected]
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Since commit 5acbf4e, when enable_parallel is off, we will insert
into only one AO segfile even gp_appendonly_insert_files is > 1.
It will make data skew after user set enable_parallel to off,
while there are a lot of data inserted later or there are
online-steaming ETL severs.
And that make our parallel plan has a bottleneck.
In general, we should try to make AO segfiles as much as GUC
gp_appendonly_insert_files and avoid data skew for users,
no matter users use parallel query or not.
And only keep gp_appendonly_insert_files default value to 4 is enough.
Remove enable_parallel when initing AO/AOCS insertDesc.
Authored-by: Zhang Mingli [email protected]
closes: #39
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make installcheckmake -C src/test installcheck-cbdb-parallel