kafka notes

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diff --git a/kafka/grobid_kafka_notes.txt b/kafka/grobid_kafka_notes.txt
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+
+Will want to be able to scale to 100-200+ fully-utilized cores running GROBID;
+how best to achieve this? will need *many* workers going concurrent HTTP GETs,
+POSTs, and Kafka publishes.
+
+I'm pretty confident we can relax "at least once"/"at most once" constraints in
+this case: infrequent re-processing and missing a tiny fraction of processed
+works should be acceptable, because we will have higher-level checks (eg, the
+'ungrobided' HBase filter/dump).
+
+For the 'ungrobided' topic, use a reasonably large number of partitions, say
+50. This sets max number of worker *processes*, and may be enough for initial
+single-host worker. We can have a python wrapper spawn many child processes
+using multiprocessing library, with completely independent kafka client
+connections in each.
+
+To get more concurrency, each consumer *process* creates a thread pool (or
+process pool?), and a Queue with fixed size. Consumes messages, pushes to
+Queue, workers threads pull and do the rest. golang sure would be nice for
+this...
+
+Need to ensure we have compression enabled, for the GROBID output in
+particular! Probably worth using "expensive" GZIP compression to get extra disk
+savings; latency shouldn't be a big deal here.
diff --git a/kafka/topics.md b/kafka/topics.md
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+
+This file lists all the Kafka topics currently used by sandcrawler (and
+fatcat).
+
+NOTE: should use `.` or `_` in topic names, but not both. We chose to use `.`
+
+ENV below is one of `prod` or `qa`.
+
+
+## Topic List
+
+All topics should default to `snappy` compression on-disk, and indefinite
+retention (on both a size and time basis).
+
+    sandcrawler-ENV.ungrobided
+        => PDF files in IA needing GROBID processing
+        => 50x partitions (huge! for worker parallelism)
+        => key: "sha1:<base32>"
+
+    sandcrawler-ENV.grobided
+        => output of GROBID processing (from pdf-ungrobided feed)
+        => could get big; 16x partitions (to distribute data)
+        => use GZIP compression (worth the overhead)
+        => key: "sha1:<base32>"; could compact
+
+    fatcat-ENV.api-crossref
+    fatcat-ENV.api-datacite
+        => all new and updated DOIs (regardless of type)
+        => full raw crossref/datacite API objects (JSON)
+        => key: lower-case DOI
+        => ~1TB capacity; 8x crossref partitions, 4x datacite
+        => key compaction possible
+
+    fatcat-ENV.oaipmh-pubmed
+    fatcat-ENV.oaipmh-arxiv
+    fatcat-ENV.oaipmh-doaj-journals (DISABLED)
+    fatcat-ENV.oaipmh-doaj-articles (DISABLED)
+        => OAI-PMH harvester output
+        => full XML resource output (just the <<record> part?)
+        => key: identifier
+        => ~1TB capacity; 4x-8x partitions
+        => key compaction possible
+
+    fatcat-ENV.api-crossref-state
+    fatcat-ENV.api-datacite-state
+    fatcat-ENV.oaipmh-pubmed-state
+    fatcat-ENV.oaipmh-arxiv-state
+    fatcat-ENV.oaipmh-doaj-journals-state (DISABLED)
+    fatcat-ENV.oaipmh-doaj-articles-state (DISABLED)
+        => serialized harvester state for ingesters
+        => custom JSON
+        => key: timespan? nothing to start
+        => 1x partitions; time/space limit Ok
+
+    fatcat-ENV.changelog
+        => small-ish objects (not fully expanded/hydrated)
+        => single partition
+        => key: could be changelog index (integer, as string)
+
+    fatcat-ENV.release-updates
+        => contains "fully" expanded JSON objects
+        => key: fcid
+        => 8x partitions
+
+
+## Create fatcat QA topics
+
+    ssh misc-vm
+    cd /srv/kafka-broker/kafka_2.12-2.0.0/bin/
+
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 50 --topic sandcrawler-qa.ungrobided
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 16 --topic sandcrawler-qa.grobided --config compression.type=gzip
+
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 1 --topic fatcat-qa.changelog
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 8 --topic fatcat-qa.release-updates
+
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 8 --topic fatcat-qa.api-crossref
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 8 --topic fatcat-qa.api-datacite
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 1 --topic fatcat-qa.api-crossref-state
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 1 --topic fatcat-qa.api-datacite-state
+
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 4 --topic fatcat-qa.oaipmh-pubmed
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 4 --topic fatcat-qa.oaipmh-arxiv
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 1 --topic fatcat-qa.oaipmh-pubmed-state
+    ./kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 2 --partitions 1 --topic fatcat-qa.oaipmh-arxiv-state
+