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From William Shen <>
Subject Re: Phoenix JDBC Connection Warmup
Date Thu, 31 Jan 2019 18:09:37 GMT
Thanks Jaanai. Do you know if that is expected only on the first query
against a table? For us, we experimented with issuing the same query
repeatedly, and we observed a slow down not only on the first query. Does
it make sense to preemptively load table metadata on start up to warm up
the system to reduce latency during the actual query time (if it is
possible to do so)?

On Wed, Jan 30, 2019 at 10:54 PM Jaanai Zhang <>

> It is expected when firstly query tables after establishing the
> connection. Something likes loads some meta information into local cache
> that need take some time,  mainly including two aspects: 1. access
> SYSTEM.CATALOG table to get schema information of the table  2. access the
> meta table of HBase to get regions information of the table
> ----------------------------------------
>    Jaanai Zhang
>    Best regards!
> William Shen <> 于2019年1月31日周四 下午1:37写道:
>> Hi there,
>> I have a component that makes Phoenix queries via the Phoenix JDBC
>> Connection. I noticed that consistently, the Phoenix Client takes longer to
>> execute a PreparedStatement and it takes longer to read through the
>> ResultSet for a period of time (~15m) after a restart of the component. It
>> seems like there is a warmup period for the JDBC connection. Is this to be
>> expected?
>> Thanks!

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