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Questions tagged [greenplum]

All versions of greenplum. Add a version-specific tag like greenplum-4.3 if that context is important.

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143 views

Why `update` and `delete` acquire EXCLUSIVE lock rather than ROW EXCLUSIVE lock in Greenplum?

As we known, insert,update and delete commands automatically acquire ROW EXCLUSIVE lock in PostgreSQL. As a fork of PostgreSQL 8.2, why in Greenplum update and delete commands automatically acquire ...
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0answers
55 views

Why gather stats on all columns?

Is there a good reason why I should not turn the column statistics down to 0 on columns that are not used in JOIN, WHERE, GROUP BY, or window functons etc.? It strikes me that the default statistics ...
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0answers
337 views

How to make Greenplum 4.2.3 only scan the intended partition?

When I uses unnest() in a View, and uses that View in a select statement, Greenplum seems to fail in only searching for the intended partition and search through all the partition of the main table ...
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61 views

Postgres_fdw Transaction isolation issue

My case I have connected to another GP DB to import data into my PostgreSQL tables and written Java schedulers to refresh it Daily. But when I'm trying to fetch the records everyday by using SQL ...
0
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1answer
30 views

Fetching rows from million rows table(Optimization)

I have millions of rows in a table of Greenplum database out of which I have to fetch around 45k rows and store them in a python List. It's taking more than 2hrs to fetch the data. How can I optimize ...
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0answers
30 views

Why might Greenplum get stuck in a loop invoking a web external table?

We have a new table partition maintenance system that went into production today, and it is failing. Each partitioned table has a web external table associated with it, and the shell script that is ...
0
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1answer
310 views

Get partition column for a table in Greenplum

How can I find what the partitioning scheme is for a table? Is it in information_schema or in the pg_class related tables?
0
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1answer
68 views

Is a partition a relation?

Is a partition a relation in its own right, or is a partitioned table a single relation? Specifically, do we need to increase max_fsm_relations when we split tables up into loads of partitions?
0
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0answers
465 views

How can a select max query return no rows?

I have a process that selects the maximum date from a Greenplum (PostgreSQL 8.2) table, and coalesces it to a default value. Once, and once only, this query returned 0 rows. How is this possible? Even ...
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0answers
163 views

Unable to exit a Greenplum SQL script

Is there any way in psql (Greenplum flavour) of exiting a script? I have tried with \q and \quit, e.g. \echo "Hello"; \q -- or \quit but I get: my_database> \i my_script.sql psql:/home/josh/...