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Decision Support Benchmark for Greenplum database.

This is the decision support (DS) benchmark derived from TPC-DS. This repo contains automation of running the DS benchmark against an existing Greenplum cluster.

Context

Supported Greenplum Versions

• VMware Greenplum 4.3.x, 5.x, 6.x, 7.x
• Open Source Greenplum Databases 5.x, 6.x

Supported TPC-DS Versions

TPC has published the following TPC-DS standards over time:

TPC-DS Benchmark Version	Published Date	Standard Specification
3.2.0 (latest)	2021/06/15	http://www.tpc.org/tpc_documents_current_versions/pdf/tpc-ds_v3.2.0.pdf
2.1.0	2015/11/12	http://www.tpc.org/tpc_documents_current_versions/pdf/tpc-ds_v2.1.0.pdf
1.3.1 (earliest)	2015/02/19	http://www.tpc.org/tpc_documents_current_versions/pdf/tpc-ds_v1.3.1.pdf

These are the combined versions of TPC-DS and Greenplum:

DS Benchmark Version	TPC-DS Benchmark Version	Greenplum Version
3.0.0	2.1.0	4.3.x, 5.x, 6.x
2.2.x	2.1.0	4.3.x, 5.x
2.x	2.1.0	4.3.x

Setup

Prerequisites

1. A running Greenplum Database with ${ADMIN_USER} access(default gpadmin)
2. ${PGDATABASE} database(default gpadmin) is created
3. root access on the master node mdw for installing dependencies
4. ssh connections between mdw and the segment nodes sdw1..n

User other than gpadmin can also execute this script provided ADMIN_USER should have equivalent access privilege of gpadmin. eg.

1. Access privilege on gpdata directory and sub-directory on each node
2. Should have read access to TPC-DS/log folder across nodes
3. ADMIN_USER database is created
4. Proper authentications set up in pg_hba.conf

All the following examples are using standard host name convention of Greenplum using mdw for master node, and sdw1..n for the segment nodes.

TPC-DS Tools Dependencies

Install the dependencies on mdw for compiling the dsdgen (data generation) and dsqgen (query generation).

ssh root@mdw
yum -y install gcc make

Note: If you are using Photon OS, then you need:

yum -y install build-essential

The original source code is from http://tpc.org/tpc_documents_current_versions/current_specifications5.asp.

Download and Install

Visit the repo at https://github.com/pivotal/TPC-DS/releases and download the tarball to the mdw node.

ssh ${ADMIN_USER}@mdw
curl -LO https://github.com/pivotal/TPC-DS/archive/refs/tags/v3.7.0.tar.gz
tar xzf v3.7.0.tar.gz
mv TPC-DS-3.7.0 TPC-DS

NOTE: default ADMIN_USER is assumed to be gpadmin

Usage

To run the benchmark, login as ${ADMIN_USER} on mdw:

ssh ${ADMIN_USER}@mdw
cd ~/TPC-DS
./tpcds.sh

NOTE: default ADMIN_USER is assumed to be gpadmin

By default, it will run a scale 1 (1G) and with 2 concurrent users, from data generation to score computation.

Configuration Options

By changing the tpcds_variables.sh, we can control how this benchmark will run.

This is the default example at tpcds_variables.sh

# environment options
ADMIN_USER=`whoami`
BENCH_ROLE="dsbench"
PGOPTIONS=""
PGDATABASE=`whoami`

# benchmark options
GEN_DATA_SCALE="1"
MULTI_USER_COUNT="2"
RNGSEED="1"
HEAP_ONLY="false"

# step options
RUN_COMPILE_TPCDS="true"
RUN_GEN_DATA="true"
RUN_INIT="true"
RUN_DDL="true"
RUN_LOAD="true"
RUN_SQL="true"
RUN_SINGLE_USER_REPORTS="true"
RUN_MULTI_USER="true"
RUN_MULTI_USER_REPORTS="true"
RUN_SCORE="true"

# misc options
SINGLE_USER_ITERATIONS="1"
EXPLAIN_ANALYZE="false"
RANDOM_DISTRIBUTION="false"

tpcds.sh will validate existence of those variables.

Environment Options

# environment options
ADMIN_USER="gpadmin"

These are the setup related variables:

• ADMIN_USER: default gpadmin. It is the default database administrator account, as well as the user accessible to all mdw and sdw1..n machines.

  Note: The benchmark related files for each segment node are located in the segment's ${PGDATA}/dsbenchmark directory. If there isn't enough space in this directory in each segment, you can create a symbolic link to a drive location that does have enough space.

In most cases, we just leave them to the default.

PSQL Environment Options

export PGPORT="6543"
# Add additional PostgreSQL refer:
# https://www.postgresql.org/docs/current/libpq-envars.html
export PGOPTIONS=""
export PGDATABASE="${ADMIN_USER}"

TPC-DS uses psql command, which interally uses libpq, to connect to the database. libpq provides environment variables that can override the default connection parameter values, which will be used by PQconnectdb, PQsetdbLogin and PQsetdb if no value is directly specified by the calling code.

Benchmark Options

# benchmark options
GEN_DATA_SCALE="1"
MULTI_USER_COUNT="2"
RNGSEED="1"
HEAP_ONLY="false"

These are the benchmark controlling variables:

• GEN_DATA_SCALE: default 1. Scale 1 is 1G.
• MULTI_USER_COUNT: default 2. It's also usually referred as CU, i.e. concurrent user. It controls how many concurrent streams to run during the throughput run.
• RNGSEED: default 1. This will generate deterministic data and queries, to reduce variance between runs due to data and query variations. Change this value to generate a different distribution to avoid over-tuning for a specific distribution.
• HEAP_ONLY: default false. When false, the benchmark will run with append-optimized table storage type. When true, the benchmark will run with heap table storage type.

If evaluating Greenplum cluster across different platforms, we recommend to change this section to 3TB with 5CU:

# benchmark options
MULTI_USER_COUNT="5"
GEN_DATA_SCALE="3000"

Step Options

# step options
RUN_COMPILE_TPCDS="true"
RUN_GEN_DATA="true"
RUN_INIT="true"
RUN_DDL="true"
RUN_LOAD="true"
RUN_SQL="true"
RUN_SINGLE_USER_REPORT="true"
RUN_MULTI_USER="true"
RUN_MULTI_USER_REPORTS="true"
RUN_SCORE="true"

There are multiple steps running the benchmark and controlled by these variables:

• RUN_COMPILE_TPCDS: default true. It will compile the dsdgen and dsqgen. Usually we only want to compile those binaries once. In the rerun, just set this value to false.
• RUN_GEN_DATA: default true. It will use the dsdgen compiled above to generate the flat files for the benchmark. The flat files are generated in parallel on all segment nodes. Those files are stored under ${PGDATA}/dsbenchmark directory. In the rerun, just set this value to false.
• RUN_INIT: default true. It will setup the GUCs for the Greenplum as well as remember the segment configurations. It's only required if the Greenplum cluster is reconfigured. It can be always true to ensure proper Greenplum cluster configuration. In the rerun, just set this value to false.
• RUN_DDL: default true. It will recreate all the schemas and tables (including external tables for loading). If you want to keep the data and just rerun the queries, please set this value to false, otherwise all the existing loaded data will be gone.
• RUN_LOAD: default true. It will load data from flat files into tables. After the load, the statistics will be computed in this step. If you just want to rerun the queries, please set this value to false.
• RUN_SQL: default true. It will run the power test of the benchmark.
• RUN_SINGLE_USER_REPORTS: default true. It will upload the results to the Greenplum database ${PGDATABASE} under schema tpcds_reports. These tables are required later on in the RUN_SCORE step. Recommend to keep it true if above step of RUN_SQL is true.
• RUN_MULTI_USER: default true. It will run the throughput run of the benchmark. Before running the queries, multiple streams will be generated by the dsqgen. dsqgen will sample the database to find proper filters. For very large database and a lot of streams, this process can take a long time (hours) to just generate the queries.
• RUN_MULTI_USER_REPORTS: default true. It will upload the results to the Greenplum database ${PGDATABASE} under schema tpcds_reports. Recommend to keep it true if above step of RUN_MULTI_USER is true.
• RUN_SCORE: default true. It will query the results from tpcds_reports and compute the QphDS based on supported benchmark standard. Recommend to keep it true if you want to see the final score of the run.

If any above variable is missing or invalid, the script will abort and show the missing or invalid variable name.

WARNING: Now TPC-DS does not rely on the log folder to run or skip the steps. It will only run the steps that are specified explicitly as true in the tpcds_variables.sh. If any necessary step is speficied as false but has never been executed before, the script will abort when it tries to access something that does not exist in the database or under the directory.

Miscellaneous Options

# misc options
EXPLAIN_ANALYZE="false"
RANDOM_DISTRIBUTION="false"
SINGLE_USER_ITERATIONS="1"

These are miscellaneous controlling variables:

• EXPLAIN_ANALYZE: default false. If you set to true, you can have the queries execute with EXPLAIN ANALYZE in order to see exactly the query plan used, the cost, the memory used, etc. This option is for debugging purpose only, since collecting those query statistics will disturb the benchmark.
• RANDOM_DISTRIBUTION: default false. If you set to true, the fact tables are distributed randomly other than following a pre-defined distribution column.
• SINGLE_USER_ITERATION: default 1. This controls how many times the power test will run. During the final score computation, the minimal/fastest query elapsed time of multiple runs will be used. This can be used to ensure the power test is in a warm run environment.

Storage Options

Table storage is defined in functions.sh and is configured for optimal performance. get_version() function defines different storage options for different scale of the benchmark.

• SMALL_STORAGE: All the dimension tables
• MEDIUM_STORAGE: catalog_returns and store_returns
• LARGE_STORAGE: catalog_sales, inventory, store_sales, and web_sales

Execution

Example of running the benchmark as root as a background process:

nohup ./tpcds.sh &> tpcds.log &

Minumum Required Query Streams

According to https://www.tpc.org/tpcds/presentations/the_making_of_tpcds.pdf, but not in the TPC-DS specification, figure 12 indicates the following minimum query streams by the scale factor.

Scale Factor	Minimum Number of Streams
100	3
300	5
1,000	7
3,000	9
10,000	11
30,000	13
100,000	15

Benchmark Minor Modifications

1. Change to SQL queries that subtracted or added days were modified slightly:

Old:

and (cast('2000-02-28' as date) + 30 days)

New:

and (cast('2000-02-28' as date) + '30 days'::interval)

This was done on queries: 5, 12, 16, 20, 21, 32, 37, 40, 77, 80, 82, 92, 94, 95, and 98.

2. Change to queries with ORDER BY on column alias to use sub-select.

Old:

select  
    sum(ss_net_profit) as total_sum
   ,s_state
   ,s_county
   ,grouping(s_state)+grouping(s_county) as lochierarchy
   ,rank() over (
 	partition by grouping(s_state)+grouping(s_county),
 	case when grouping(s_county) = 0 then s_state end 
 	order by sum(ss_net_profit) desc) as rank_within_parent
 from
    store_sales
   ,date_dim       d1
   ,store
 where
    d1.d_month_seq between 1212 and 1212+11
 and d1.d_date_sk = ss_sold_date_sk
 and s_store_sk  = ss_store_sk
 and s_state in
             ( select s_state
               from  (select s_state as s_state,
 			    rank() over ( partition by s_state order by sum(ss_net_profit) desc) as ranking
                      from   store_sales, store, date_dim
                      where  d_month_seq between 1212 and 1212+11
 			    and d_date_sk = ss_sold_date_sk
 			    and s_store_sk  = ss_store_sk
                      group by s_state
                     ) tmp1 
               where ranking <= 5
             )
 group by rollup(s_state,s_county)
 order by
   lochierarchy desc
  ,case when lochierarchy = 0 then s_state end
  ,rank_within_parent
 limit 100;

New:

select * from ( --new
select  
    sum(ss_net_profit) as total_sum
   ,s_state
   ,s_county
   ,grouping(s_state)+grouping(s_county) as lochierarchy
   ,rank() over (
 	partition by grouping(s_state)+grouping(s_county),
 	case when grouping(s_county) = 0 then s_state end 
 	order by sum(ss_net_profit) desc) as rank_within_parent
 from
    store_sales
   ,date_dim       d1
   ,store
 where
    d1.d_month_seq between 1212 and 1212+11
 and d1.d_date_sk = ss_sold_date_sk
 and s_store_sk  = ss_store_sk
 and s_state in
             ( select s_state
               from  (select s_state as s_state,
 			    rank() over ( partition by s_state order by sum(ss_net_profit) desc) as ranking
                      from   store_sales, store, date_dim
                      where  d_month_seq between 1212 and 1212+11
 			    and d_date_sk = ss_sold_date_sk
 			    and s_store_sk  = ss_store_sk
                      group by s_state
                     ) tmp1 
               where ranking <= 5
             )
 group by rollup(s_state,s_county)
) AS sub --new
 order by
   lochierarchy desc
  ,case when lochierarchy = 0 then s_state end
  ,rank_within_parent
 limit 100;

This was done on queries: 36 and 70.

3. Query templates were modified to exclude columns not found in the query.

In these cases, the common table expression used aliased columns but the dynamic filters included both the alias name as well as the original name. Referencing the original column name instead of the alias causes the query parser to not find the column.

This was done on query 86.

4. Added table aliases.

This was done on queries: 2, 14, and 23.

5. Added limit 100 to very large result set queries.

For the larger tests (e.g. 15TB), a few of the TPC-DS queries can output a very large number of rows which are just discarded.

This was done on queries: 64, 34, and 71.

6. Changed integer to bigint to handle larger scale.

For larger tests (50TB and up), data load will fail due to out of range numbers.

This is done on loading of web_sales, and web_returns.

Development

Prerequisites

• shellcheck: https://github.com/koalaman/shellcheck
• shfmt: https://github.com/mvdan/sh

Linting

make lint