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https://issues.apache.org/jira/browse/BEAM-2154?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15995960#comment-15995960
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ASF GitHub Bot commented on BEAM-2154:
--------------------------------------
GitHub user reuvenlax opened a pull request:
https://github.com/apache/beam/pull/2883
[BEAM-2154] Make BigQuery's dynamic-destination support scale to large
numbers of destinations
Generating hundreds or thousands of file write buffers in a single bundle
was causing workers to crash with out of memory. We now detect when too many
files have been written in a bundle, and spill the remaining records to another
PCollection. This PCollection is then grouped by destination before we write
the remaining data to files. We shard destination keys 10 ways to prevent
hotspotting. Tests of up to 10TB of data (going from 20 output tables up to
4000) were run, and a sharding factor of 10 seems to work quite well on all
runs (and is noticeably faster than not sharding)
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/reuvenlax/incubator-beam bigquery_scalability
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/beam/pull/2883.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #2883
----
commit 45eb1f8ec1f84a3eefd6d85539e9dc433be4842f
Author: Reuven Lax <re...@google.com>
Date: 2017-04-29T14:33:54Z
If too many tables are generated in a bundle, spill and group the results
before writing files. Generating hundreds or thousands of file write buffers in
a single bundle was causing workers to crash with out of memory.
----
> Writing to large numbers of BigQuery tables causes out-of-memory
> -----------------------------------------------------------------
>
> Key: BEAM-2154
> URL: https://issues.apache.org/jira/browse/BEAM-2154
> Project: Beam
> Issue Type: Bug
> Components: sdk-java-gcp
> Reporter: Reuven Lax
> Assignee: Reuven Lax
> Fix For: First stable release
>
>
> Since all TableRowWriters are created in a single DoFn, the write buffers all
> exist simultaneously and use up large amounts of memory.
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