Author Archives: ruihaijiang

Example query

SELECT c.tstamp [target list] FROM commits c, actions a [range table] WHERE a.file IN [qualifier] (SELECT id FROM files [IN-clause subquery] WHERE path = ’…’) AND a.commit_id = c.id [join predicate] ORDER BY c.tstamp DESC [sort order] LIMIT 1; [limit … Continue reading

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PostgreSQL Planner

Query Plan: a tree of plan nodes; each node is a single operation (join, disk scan, sort, etc.) Planner: generate path, then generate Query Plans. Planning outer joins Planning subqueries Planning expression subqueries Planning functions Planning set operations Plan node: … Continue reading

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PostgreSQL references

http://www.postgresql.org/docs/8.4/static/biblio.html Query Planner http://www.postgresql.org/docs/9.1/static/geqo-pg-intro.html Bruce MomJian http://momjian.us/main/presentations/internals.html Postgres-XL

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Postgres-XL Installation Example on Linux

1. Overview In this example, we use pgxc_ctl to configure a Postgres-XL cluster for test only. The cluster includes 4 nodes, 1 GTM, 1 Coordinator and 2 Datanodes. Each node is deployed on a separate host so there are totally … Continue reading

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