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https://issues.apache.org/jira/browse/PHOENIX-1596?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14299240#comment-14299240
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Samarth Jain commented on PHOENIX-1596:
---------------------------------------
When tracing scans we can't use trace scope because closing the scope will
close the child span too. And we want to close the child span only when the
scanner is being closed. On taking a closer look, I don't think we need the
Tracing.childOnServer() call at all. Setting of tracing attributes in case of
mutations is taken care by the client when it issues a connection.commit() on a
traceable connection. These attributes are then read by the CallRunner (as
TraceInfo) on the region server side to start tracing. See
org.apache.hadoop.hbase.ipc#run().
> Setting tracing frequency to ALWAYS on the client side results in too many
> traces
> ---------------------------------------------------------------------------------
>
> Key: PHOENIX-1596
> URL: https://issues.apache.org/jira/browse/PHOENIX-1596
> Project: Phoenix
> Issue Type: Bug
> Reporter: Samarth Jain
> Attachments: PHOENIX-1596.patch
>
>
> After setting trace collection frequency to always by setting the following
> in hbase-site.xml, I noticed that it created way too many traces in the trace
> table.
> <property>
> <name>phoenix.trace.frequency</name>
> <value>always</value>
> </property>
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 1283 |
> +------------------------------------------+
> 1 row selected (1.104 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 4051 |
> +------------------------------------------+
> 1 row selected (1.058 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 10668 |
> +------------------------------------------+
> 1 row selected (1.105 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 11361 |
> +------------------------------------------+
> 1 row selected (1.046 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 193119 |
> +------------------------------------------+
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 1283 |
> +------------------------------------------+
> 1 row selected (1.104 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 4051 |
> +------------------------------------------+
> 1 row selected (1.058 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 10668 |
> +------------------------------------------+
> 1 row selected (1.105 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 11361 |
> +------------------------------------------+
> 1 row selected (1.046 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> +------------------------------------------+
> | COUNT(1) |
> +------------------------------------------+
> | 193119 |
> +------------------------------------------+
> 1 row selected (6.737 seconds)
> 0: jdbc:phoenix:localhost> select count (*) from system.tracing_stats;
> 15/01/19 17:26:57 WARN client.HConnectionManager$HConnectionImplementation:
> This client just lost it's session with ZooKeeper, closing it. It will be
> recreated next time someone needs it
> Even though the only query that was being executed was the select count(*) to
> get the number of rows in the trace table, it ended up creating way too many
> traces than I had expected.
> On my mac, it in fact ended up killing the local hbase cluster altogether!
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