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https://issues.apache.org/jira/browse/PHOENIX-808?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15427323#comment-15427323
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James Taylor commented on PHOENIX-808:
--------------------------------------
Thanks for the patch, [~samarthjain]. Here's some feedback:
- In general, restoring multiple system tables is tricky. For example, keeping
the new system.catalog might not be good if the upgrading of the
system.sequence fails. For simplicity, I'd stick with solely
snapshoting/restoring only the system.catalog and revert back to the old one if
any anything fails across the upgrade of any of the system tables.
- How about we just remove the upgrade code in both system.sequence and
system.stats? The upgrade code there is way older than anything our b/w compat
contract supports (all the way five version back to 4.2 and 4.3). The sequence
upgrade is a noop now too, since by default we don't salt the sequence table.
That way, there's no upgrade anyway for the other tables.
- Might be best to put the enableTable here in a finally block so that if the
restore were to fail we'd still leave the table in an enabled state:
{code}
+ private void restoreFromSnapshot(String tableName, String
snapshotName,
+ boolean success) throws IOException,
RestoreSnapshotException, SQLException {
+ if (!success && snapshotName != null) {
+ try (HBaseAdmin admin = getAdmin()) {
+ logger.warn("Starting restore of " + tableName + "
using snapshot " + snapshotName + " because upgrade failed");
+ admin.disableTable(tableName);
+ admin.restoreSnapshot(snapshotName);
+ admin.enableTable(tableName);
+ logger.warn("Successfully restored " + tableName +
" using snapshot " + snapshotName);
+ }
+ }
+ }
{code}
> Create snapshot of system tables prior to upgrade and restore on any failure
> ----------------------------------------------------------------------------
>
> Key: PHOENIX-808
> URL: https://issues.apache.org/jira/browse/PHOENIX-808
> Project: Phoenix
> Issue Type: Task
> Reporter: James Taylor
> Assignee: Samarth Jain
> Attachments: PHOENIX-808.patch, PHOENIX-808_master.patch,
> PHOENIX-808_nowhitespace.patch
>
>
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