Greenplum "ERROR: target lists can have at most 1664 entries"

Overview 

This article describes "ERROR: target list can have at most 1664 enties". Experiment described in article was tested on Greenplum 5.5.

Greenplum has limitation on number of columns that can be mentioned in projection list of select query. There can be maximum 1664 column in projection list of SELECT query. Hence, while executing SELECT query containing >1664 columns will lead to such error.

Consider table having number of columns > 832. We can also hit "ERROR: target list can have at most 1664 enties" error while inserting row/s with any number of columns into such table.

Table Statistics Collection 

Greenplum provides feature of analyzing tables and collecting statistics. These statistics can be used for generating cost optimised query plan. The ANALYZE statement which can be used by end user to trigger table analysis manually. There exist automatic statistics collection functionality in greenplum due to which table is ANALYZed and Statistics are collected whenever rows are inserted in table. The value of gp_autostat_mode configuration parameter decides wether automatic statistics should be triggered or not.

While collecting table statistics, analyzer executes some SELECT statements to extract stored data size. That means SELECTs projecting all table columns are executed. One of the statistics collection SELECT projects each column twice (after applying certain functions).

Following is example of statistics gathering select under discussion for table named tab1 with single column id1. 

Considering Greenplum's limitation of 1664 columns in projection list , it is obvious to hit "ERROR: target list can have at most 1664 enties" while  inserting row/s into table having >832 columns.

References 

1. https://github.com/greenplum-db/gpdb/issues/1345
2. https://gpdb.docs.pivotal.io/550/admin_guide/topics/g-automatic-statistics-collection-parameters.html
3. https://gpdb.docs.pivotal.io/550/ref_guide/sql_commands/ANALYZE.html