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https://issues.apache.org/jira/browse/BEAM-5428?focusedWorklogId=320517&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-320517
]
ASF GitHub Bot logged work on BEAM-5428:
----------------------------------------
Author: ASF GitHub Bot
Created on: 30/Sep/19 14:21
Start Date: 30/Sep/19 14:21
Worklog Time Spent: 10m
Work Description: mxm commented on pull request #9418: [BEAM-5428]
Implement cross-bundle user state caching in the Python SDK
URL: https://github.com/apache/beam/pull/9418#discussion_r329604291
##########
File path: sdks/python/apache_beam/runners/worker/sdk_worker.py
##########
@@ -620,6 +632,93 @@ def _next_id(self):
return str(self._last_id)
+class CachingMaterializingStateHandler(object):
+ """ A State handler which retrieves and caches state. """
+
+ def __init__(self, global_state_cache, underlying_state):
+ self._underlying = underlying_state
+ self._state_cache = global_state_cache
+ self._context = threading.local()
+
+ @contextlib.contextmanager
+ def process_instruction_id(self, bundle_id, cache_tokens):
+ if getattr(self._context, 'cache_token', None) is not None:
+ raise RuntimeError(
+ 'Cache tokens already set to %s' % self._context.cache_token)
+ # TODO Also handle cache tokens for side input, if present:
+ # https://issues.apache.org/jira/browse/BEAM-8298
+ user_state_cache_token = None
+ for cache_token_struct in cache_tokens:
+ if cache_token_struct.HasField("user_state"):
+ # There should only be one user state token present
+ assert not user_state_cache_token
+ user_state_cache_token = cache_token_struct.token
+ try:
+ self._context.cache_token = user_state_cache_token
+ with self._underlying.process_instruction_id(bundle_id):
+ yield
+ finally:
+ self._context.cache_token = None
+
+ def blocking_get(self, state_key, coder, is_cached=False):
+ if not self._should_be_cached(is_cached):
+ # no cache / tokens, can't do a lookup/store in the cache
+ return self._materialize_iter(state_key, coder)
+ # Cache lookup
+ cache_state_key = self._convert_to_cache_key(state_key)
+ cached_value = self._state_cache.get(cache_state_key,
+ self._context.cache_token)
+ if cached_value is None:
+ # Cache miss, need to retrieve from the Runner
+ materialized = cached_value = list(
Review comment:
Without a size optimization, I don't think there is much we can do at the
moment. For large state, the continuation token could be used, but it is not
utilized by the Runner for now.
Considering that state caching is disabled for now and the previous state
materialization strategy (lazily fetch one item at a time) has not been
altered, it seems fair to address this in a follow-up and mark this a TODO for
now.
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Issue Time Tracking
-------------------
Worklog Id: (was: 320517)
Time Spent: 26h 20m (was: 26h 10m)
> Implement cross-bundle state caching.
> -------------------------------------
>
> Key: BEAM-5428
> URL: https://issues.apache.org/jira/browse/BEAM-5428
> Project: Beam
> Issue Type: Improvement
> Components: sdk-py-harness
> Reporter: Robert Bradshaw
> Assignee: Maximilian Michels
> Priority: Major
> Time Spent: 26h 20m
> Remaining Estimate: 0h
>
> Tech spec:
> [https://docs.google.com/document/d/1BOozW0bzBuz4oHJEuZNDOHdzaV5Y56ix58Ozrqm2jFg/edit#heading=h.7ghoih5aig5m]
> Relevant document:
> [https://docs.google.com/document/d/1ltVqIW0XxUXI6grp17TgeyIybk3-nDF8a0-Nqw-s9mY/edit#|https://docs.google.com/document/d/1ltVqIW0XxUXI6grp17TgeyIybk3-nDF8a0-Nqw-s9mY/edit]
> Mailing list link:
> [https://lists.apache.org/thread.html/caa8d9bc6ca871d13de2c5e6ba07fdc76f85d26497d95d90893aa1f6@%3Cdev.beam.apache.org%3E]
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