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https://issues.apache.org/jira/browse/BEAM-11097?focusedWorklogId=665221&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-665221
]
ASF GitHub Bot logged work on BEAM-11097:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 13/Oct/21 18:56
Start Date: 13/Oct/21 18:56
Worklog Time Spent: 10m
Work Description: lostluck commented on a change in pull request #15717:
URL: https://github.com/apache/beam/pull/15717#discussion_r728225713
##########
File path: sdks/go/pkg/beam/core/runtime/harness/statecache/statecache.go
##########
@@ -44,18 +52,19 @@ type token string
type SideInputCache struct {
capacity int
mu sync.Mutex
- cache map[token]exec.ReStream
+ cache map[cacheKey]exec.ReStream
idsToTokens map[string]token
validTokens map[token]int8 // Maps tokens to active bundle counts
metrics CacheMetrics
}
// CacheMetrics stores metrics for the cache across a pipeline run.
type CacheMetrics struct {
- Hits int64
- Misses int64
- Evictions int64
- InUseEvictions int64
+ Hits *metrics.Counter
+ Misses *metrics.Counter
+ Evictions *metrics.Counter
+ InUseEvictions *metrics.Counter
+ ReStreamErrors *metrics.Counter
Review comment:
style nit: Go permits singlelining field declarations when the types are
the same, for scenarios exactly like this.
`Hits, Misses, Evictions, InUseEvictions, ReStreamErrors int64`
##########
File path: sdks/go/pkg/beam/core/runtime/harness/statecache/statecache.go
##########
@@ -145,19 +150,24 @@ func (c *SideInputCache)
makeAndValidateToken(transformID, sideInputID string) (
return tok, c.isValid(tok)
}
+func (c *SideInputCache) makeCacheKey(tok token, w, key []byte) cacheKey {
+ return cacheKey{tok: tok, win: string(w), key: string(key)}
+}
+
// QueryCache takes a transform ID and side input ID and checking if a
corresponding side
// input has been cached. A query having a bad token (e.g. one that doesn't
make a known
// token or one that makes a known but currently invalid token) is treated the
same as a
// cache miss.
-func (c *SideInputCache) QueryCache(transformID, sideInputID string)
exec.ReStream {
+func (c *SideInputCache) QueryCache(ctx context.Context, transformID,
sideInputID string, win, key []byte) exec.ReStream {
c.mu.Lock()
defer c.mu.Unlock()
tok, ok := c.makeAndValidateToken(transformID, sideInputID)
if !ok {
return nil
}
+ keyString := c.makeCacheKey(tok, win, key)
Review comment:
nit: No longer a string, and the scope is 3 lines, so just call it
`ck`. Ths is a Go Idiom, the shorter the distance a name needs to travel, the
shorter it can be. The shortness indicates that it's definition is likely not
far away or it's fairly standard (like using r and w for io.Reader and
io.Writer values).
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Issue Time Tracking
-------------------
Worklog Id: (was: 665221)
Time Spent: 12h 10m (was: 12h)
> [Go SDK] Windowed Side Input Caching (Cross Bundle)
> ---------------------------------------------------
>
> Key: BEAM-11097
> URL: https://issues.apache.org/jira/browse/BEAM-11097
> Project: Beam
> Issue Type: Improvement
> Components: sdk-go
> Reporter: Robert Burke
> Assignee: Jack McCluskey
> Priority: P3
> Labels: starter
> Time Spent: 12h 10m
> Remaining Estimate: 0h
>
> This is implementing https://issues.apache.org/jira/browse/BEAM-5428 for the
> Go SDK.
> Side inputs are valid for given window. That means they can be and correctly
> cached and re-used in multiple bundles if the data has already been loaded
> into a given worker.
> Side input data for a given bundle is specified and keyed by the window and a
> a side input request token. The Go SDK presently doesn't use this information
> for a SDK side worker cache of data.
> Care needs to be taken to allow the data to be garbage collected if it hasn't
> been used in the last minute or so. In practice, Global Window side inputs
> will not be evicted while still in use, but infrequently accessed data will
> possibly be evicted more regularly. A limit should be set to avoid running
> out of memory.
> As presently implemented, each ProcessElement call (or StartBundle or
> FinishBundle) will only query for side input data on user request. However,
> results of user requests are not cached between elements or bundles, which
> means there's additional lookup and serialization time from the runner side.
> It may be possible to re-use allocated side input elements, but even a
> solution that re-decodes data on every call would be an improvement if the
> data isn't re-streamed from the runner.
> If https://issues.apache.org/jira/browse/BEAM-3293 has been implemented, then
> per-key+window caching should additionally be considered for more granular
> caching of data.
> This optimization has an outsized impact on streaming performance as side
> input data can change per bundle, and streaming bundles are typically small,
> and quickly processed.
> This work would be implemented in the exec package:
>
> [https://github.com/apache/beam/blob/master/sdks/go/pkg/beam/core/runtime/exec/sideinput.go]
>
> and probably the harness package
>
> [https://github.com/apache/beam/blob/c185adb7652034b5d044aae65a1a972d9ceb4377/sdks/go/pkg/beam/core/runtime/harness/statemgr.go#L50]
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