Faster shard loading #5372
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Faster shard loading #5372
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@dswarbrick @toddboom Would be interested to see if this improves startup times of some larger DBs. |
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@jwilder tested this on a smaller database this morning with inconclusive results (there's one large shard that takes all of the time, so parallelization didn't matter), but will test it on the larger datasets this afternoon. |
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This needs to be rebased FYI. |
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Yes. I may need to revert some changes in here as well. |
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| @@ -203,23 +209,35 @@ func (f *FileStore) Remove(paths ...string) { | |||
| sort.Sort(tsmReaders(f.files)) | |||
| } | |||
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| func (f *FileStore) Keys() []string { | |||
| func (f *FileStore) WalkKeys(fn func(key string, typ byte) error) error { | |||
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LGTM |
| values = getFloat64Values(nvals) | ||
| for i := 0; i < nvals; i++ { | ||
| values[i] = &FloatValue{} | ||
| } | ||
| case integerEntryType: | ||
| values = getIntegerValues(nvals) |
When loading many shards concurrently they block trying to acquire a write lock in the sync pool adding a new source of contention. Since this code flow always needs to allocate a buffer it's not really buying us much.
Since loading a shard can allocate a lot of memory, running them all at once could OOM the process. This limits the number of shards loaded to 4. This will be changed to a config option provided the approach helps.
Avoids allocating a big map or all keys.
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This PR improves startup times for databases with many shards. The main changes are:
Should help #5311.