Viewing Data Distribution in v4.x To view the data distribution of a table’s rows (the number of rows on each segment), you can run a query such as: # SELECT gp_segment_id, count(*) FROM table_name GROUP BY gp_segment_id; To see the data distribution of a table’s rows on segment servers and the directory location of where the data is located, you can run a query such as: # SELECT table_name.gp_segment_id,hostname, fselocation as datadir,count(*) FROM table_name, pg_filespace_entry pgfse,gp_segment_configuration gsc WHERE gsc.dbid=pgfse.fsedbid and table_name.gp_segment_id= pgfse.fsedbid GROUP BY table_name.gp_segment_id,hostname,datadir ORDER BY gp_segment_id; Notes: Balanced Distribution A table is considered to have a balanced distribution if all of the segments have roughly the same number of rows. |
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