let access-follower reload region on no candidate #901
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Signed-off-by: zyguan <[email protected]>
cfzjywxk
reviewed
Jul 24, 2023
| if len(c.regionsNeedReload.regions) < maxPendingReloadRegions { | ||
| c.regionsNeedReload.regions = append(c.regionsNeedReload.regions, regionID) | ||
| } else { | ||
| c.regionsNeedReload.regions[rand.Intn(maxPendingReloadRegions)] = regionID |
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For this strategy, there seem to be starvation possibilities if scheduleReloadRegion keeps happening and no one can make progress.
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And the region whose reload is canceled should be set to non-async status(set region.asyncReload to 0), unless it'll not be reloaded in the future.
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Why not just ignore in this situation? Random indicates unpredictable...
|
#1122 is the better solution. |
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Fix #879.
#843 only reload region when a failed store becomes reachable, thus can not handle issues like #879. This PR solve the issue by scheduling region reload when there is no candidate. To avoid reload region too frequently, it also limited the max number of pending reload regions.
With this PR, cross AZ traffic shall be reduced during the down-peer scheduling: