Allow a cluster to run in a skewed clock mode #10932
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mbautin
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Feb 12, 2022
Summary: In some cases it might be useful to shift a cluster's notion of hybrid time by a fixed delta. This is done by passing the following flag to masters and tablet servers: --time_source=skewed,some_value_ms. There are a few things that we need to do to improve the cluster operation in such cases: - Allow the closing timestamp of WAL segments to be assigned with a similar clock skew. WAL segment closing timestamps are assigned using wall clock in case of successfully writing the footer, and using the hybrid time in case of footer rebuild. The wall clock case needs to be shifted by the clock skew delta in the wall clock case. - Modify the log GC mechanism so that WAL segments are retained for the specified amount of time even though their closing timestamp is assigned with a clock skew. Also in this diff we log errors that might happen when determining the WAL data size eligible for garbage collection, instead of silently ignoring them. Test Plan: Jenkins Reviewers: rsami Reviewed By: rsami Subscribers: ybase, bogdan Differential Revision: https://phabricator.dev.yugabyte.com/D14482
jayant07-yb
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Mar 8, 2022
Summary: In some cases it might be useful to shift a cluster's notion of hybrid time by a fixed delta. This is done by passing the following flag to masters and tablet servers: --time_source=skewed,some_value_ms. There are a few things that we need to do to improve the cluster operation in such cases: - Allow the closing timestamp of WAL segments to be assigned with a similar clock skew. WAL segment closing timestamps are assigned using wall clock in case of successfully writing the footer, and using the hybrid time in case of footer rebuild. The wall clock case needs to be shifted by the clock skew delta in the wall clock case. - Modify the log GC mechanism so that WAL segments are retained for the specified amount of time even though their closing timestamp is assigned with a clock skew. Also in this diff we log errors that might happen when determining the WAL data size eligible for garbage collection, instead of silently ignoring them. Test Plan: Jenkins Reviewers: rsami Reviewed By: rsami Subscribers: ybase, bogdan Differential Revision: https://phabricator.dev.yugabyte.com/D14482
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In some cases it is useful to shift a cluster's notion of hybrid time by a fixed delta. This is done using the following flag to masters and tablet servers:
--time_source=skewed,some_value_ms. There are a few things that we need to do to improve the cluster operation in such cases:The text was updated successfully, but these errors were encountered: