ON MASTER is ignored in writable external table using S3 protocol on Tanzu Greenplum
Article ID: 296738
Updated On:
Products
Issue/Introduction
It is possible to specify "ON MASTER" directive when creating readable or writable external tables that use the S3 or custom protocols.
From "Create External Table" documentation:
ON MASTER
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Restricts all table-related operations to the Greenplum master segment. Permitted only on readable and writable external tables created with the s3 or custom protocols. The gpfdist, gpfdists, pxf, and file protocols do not support ON MASTER.
This directive will ensure all reads from and writes to the external location to be done on the master only.
However when "ON MASTER" is specified for an external writable table, the directive is ignored.
All of the writes to the external location will be executed on the segments.
Even when taking a schema backup of the table the "ON MASTER" directive will not be backed up.
The "ON MASTER" directive functions correctly for readable external tables.
Environment
Resolution
The issue is fixed in 6.20.2.
On Master is now supported for s3 external table.
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