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Greenplum Tutorial
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Download the Greenplum Sandbox VM 30 minLecture1.1
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Greenplum Database Architecture 30 minLecture1.2
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Greenplum Configuration Files ( pg_hba.conf , postgresql.conf ) 30 minLecture1.3
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Greenplum Database Installation 30 minLecture1.4
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Greenplum psql Command Line Client 30 minLecture1.5
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Greenplum Create Users and Roles 30 minLecture1.6
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Greenplum Create and Prepare Database 30 minLecture1.7
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Greenplum Create Tables 30 minLecture1.8
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Greenplum Data Loading 30 minLecture1.9
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Greenplum Performance Tuning
7-
Greenplum Performance Tuning Overview 30 minLecture2.1
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Greenplum Analyze the tables 30 minLecture2.2
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Greenplum explain plans 30 minLecture2.3
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Greenplum Indexes and performance 30 minLecture2.4
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Greenplum Row vs. column orientation 30 minLecture2.5
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Greenplum – Check for even data distribution on segments 30 minLecture2.6
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Greenplum Partitioning 30 minLecture2.7
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Greenplum Database Analytics
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Greenplum Database analytics 30 minLecture3.1
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Greenplum Backup and Recovery Operations
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Greenplum gpcrondump 30 minLecture4.1
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Greenplum gpdbrestore 30 minLecture4.2
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Importing GPDB Sandbox
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Importing GPDB Sandbox into VMware Fusion 30 minLecture5.1
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Greenplum Database Books
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Data Warehousing with Greenplum PDF 30 minLecture6.1
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Basic Questions and Answer of Greenplum Database
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Some basic Questions and answer about Greenplum database 30 minLecture7.1
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Greenplum Row vs. column orientation
Greenplum Database offers the ability to store a table in either row or column orientation. Both storage options have advantages, depending upon data compression characteristics, the kinds of queries executed, the row length, and the complexity and number of join columns.
As a general rule, very wide tables are better stored in row orientation, especially if there are joins on many columns. Column orientation works well to save space with compression and to reduce I/O when there is much duplicated data in columns.
In this exercise, you will create a column-oriented version of the fact table and compare it with the row-oriented version.
- Create a column-oriented version of the FAA On Time Performance fact table and insert the data from the row-oriented version.
tutorial=# CREATE TABLE FAA.OTP_C (LIKE faa.otp_r) WITH (appendonly=true, orientation=column) DISTRIBUTED BY (UniqueCarrier, FlightNum) PARTITION BY RANGE(FlightDate) ( PARTITION mth START('2009-06-01'::date) END ('2010-10-31'::date) EVERY ('1 mon'::interval)); tutorial=# INSERT INTO faa.otp_c SELECT * FROM faa.otp_r; - Compare the definitions of the row and the column versions of the table.
tutorial=# \d faa.otp_r Table "faa.otp_r" Column | Type | Modifiers ----------------------+------------------+----------- flt_year | smallint | flt_quarter | smallint | flt_month | smallint | flt_dayofmonth | smallint | flt_dayofweek | smallint | flightdate | date | uniquecarrier | text | airlineid | integer | carrier | text | flightnum | text | origin | text | origincityname | text | originstate | text | originstatename | text | dest | text | destcityname | text | deststate | text | deststatename | text | crsdeptime | text | deptime | integer | depdelay | double precision | depdelayminutes | double precision | departuredelaygroups | smallint | taxiout | smallint | wheelsoff | text | wheelson | text | taxiin | smallint | crsarrtime | text | arrtime | text | arrdelay | double precision | arrdelayminutes | double precision | arrivaldelaygroups | smallint | cancelled | smallint | cancellationcode | text | diverted | smallint | crselapsedtime | integer | actualelapsedtime | double precision | airtime | double precision | flights | smallint | distance | double precision | distancegroup | smallint | carrierdelay | smallint | weatherdelay | smallint | nasdelay | smallint | securitydelay | smallint | lateaircraftdelay | smallint | Distributed by: (uniquecarrier, flightnum)Notice that the column-oriented version is append-only and partitioned. It has seventeen child files for the partitions, one for each month from June 2009 through October 2010.
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tutorial=# \d faa.otp_c Append-Only Columnar Table "faa.otp_c" Column | Type | Modifiers ----------------------+------------------+----------- flt_year | smallint | flt_quarter | smallint | flt_month | smallint | flt_dayofmonth | smallint | flt_dayofweek | smallint | flightdate | date | uniquecarrier | text | airlineid | integer | carrier | text | flightnum | text | origin | text | origincityname | text | originstate | text | originstatename | text | dest | text | destcityname | text | deststate | text | deststatename | text | crsdeptime | text | deptime | integer | depdelay | double precision | depdelayminutes | double precision | departuredelaygroups | smallint | taxiout | smallint | wheelsoff | text | wheelson | text | taxiin | smallint | crsarrtime | text | arrtime | text | arrdelay | double precision | arrdelayminutes | double precision | arrivaldelaygroups | smallint | cancelled | smallint | cancellationcode | text | diverted | smallint | crselapsedtime | integer | actualelapsedtime | double precision | airtime | double precision | flights | smallint | distance | double precision | distancegroup | smallint | carrierdelay | smallint | weatherdelay | smallint | nasdelay | smallint | securitydelay | smallint | lateaircraftdelay | smallint | Checksum: t Number of child tables: 17 (Use \d+ to list them.) Distributed by: (uniquecarrier, flightnum) Compare the sizes of the tables using the pg_relation_size() and pg_total_relation_size() functions. The pg_size_pretty() function converts the size in bytes to human-readable units.
tutorial=# SELECT pg_size_pretty(pg_relation_size('faa.otp_r')); pg_size_pretty ---------------- 256 MB (1 row) tutorial=# SELECT pg_size_pretty(pg_total_relation_size('faa.otp_r')); pg_size_pretty ---------------- 256 MB (1 row) tutorial=# SELECT pg_size_pretty(pg_relation_size('faa.otp_c')); pg_size_pretty ---------------- 0 bytes (1 row) tutorial=# SELECT pg_size_pretty(pg_total_relation_size('faa.otp_c')); pg_size_pretty ---------------- 288 kB (1 row)
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