On 5/27/21 4:58 PM, Rob Sargent wrote:
On 5/27/21 3:08 PM, Sam Gendler wrote:
The same JDBC connection that is resulting in lost data? Sounds to me
like you aren't connecting to the DB you think you are connecting to.
I almost wish that were true.
However, looking at AWS "Performance Insights" is see the sql statements
generate by my app begin executed on the server. Not coincidentally this
is from the "Top SQL (10)/Load by waits" view. Now that view does NOT, in
point of fact, name the database in which the sql is running, but the rest
of my environment pretty much rules out silently switching tracks on
myself. I have to read from the correct database, using a UUID, to get
data to analyze, then save the results of the analysis back. I'm using my
wonderful webapp to run this and I've successfully analyzed and stored
result for small starting data sets.
I just notice the "Top database" tab on that screen: there is only one
and it's the correct one.
I've reproduced the behaviour. I'm pretty convinced it a size thing, but
which part of the system is being max'd out is not clear. Not CPU, but
that's the only resource the "Performance Insight" mentions (suggesting
this UI wasn't designed by a database person).
The loss of the staging table is most spectacular. It filled from a file
which has 7.5M records. It's clear in the tomcat logs that is was created
and written to, one record read. Then the "top sql" happens:
insert into segment select * from
bulk."rjs_GEV15_01_c9e224ca_85d2_40b4_ad46_327cfb9f0ac6" as s where
s.probandset_id >= ? and s.probandset_id < ?
the "bulk" table is the staging table. The params are filled in with a
quasi-uuid which grab roughly 1/16th of the data. In the stack trace on
my tomcat server I get
Caused by: org.jooq.exception.DataAccessException: SQL [insert into
segment select * from
bulk."rjs_GEV15_01_c9e224ca_85d2_40b4_ad46_327cfb9f0ac6" as s where
s.probandset_id >= '30000000-0000-0000-0000-00000000\
0000' and s.probandset_id < '40000000-0000-0000-0000-000000000000' ];
An I/O error occurred while sending to the backend.
So this would have been the fourth such insert statement read from that
staging table.
That table is not deleted by my code. It is renamed after the last insert
into segment, by appending "_done" to the name. But that table, by either
name, is nowhere to be seen on the server.
For those scoring at home, the trouble in the tomcat log start with
0:02:11.452 [https-jsse-nio-10.0.2.28-15002-exec-7] INFO
edu.utah.camplab.jx.PayloadFromMux -
Is there any way to replicate this in psql?
--
Angular momentum makes the world go 'round.
