The In-Memory Column Index (IMCI) significantly accelerates complex SQL query operations. It can improve query performance by more than 50 times compared to the row store engine. This topic uses data tables and SQL statements from the TPC-H benchmark to demonstrate the advantages of IMCI.
The TPC-H performance test described in this topic is implemented based on the TPC-H benchmark test but cannot meet all requirements of the TPC-H benchmark test. Therefore, the test results cannot be compared with the published results of the TPC-H benchmark test.
Test description
TPC-H is a commonly used performance benchmark developed and released by the Transaction Processing Performance Council (TPC) to evaluate the analytical capabilities of databases. The dataset for this IMCI query test includes 8 data tables. The test executes 22 complex SQL queries that involve operations such as single-table statistics, multi-table joins, subqueries, aggregations, and sorting.
Test data size: 100 GB.
Test environment:
ECS:
Instance type: 16-core 32 GB (ecs.c5.4xlarge), with more than 150 GB of attached disk space.
Image: Alibaba Cloud Linux 3.2104 LTS 64-bit.
PolarDB for PostgreSQL cluster:
Database engine: PostgreSQL 14, with minor engine version 14.10.20.0 or later.
Edition: Enterprise Edition.
Series: Dedicated.
Specifications: 32-core 256 GB.
NoteMake sure that the ECS instance and the PolarDB cluster are in the same virtual private cloud (VPC).
Data preparation
On the PolarDB for PostgreSQL cluster, create a privileged account and create the test database
tpchdb.Log on to the ECS instance and prepare the test data.
Download the TPC-H tool dbgen.tar.gz, upload it to the ECS instance, and then decompress and compile it.
--- Decompress the package tar -zxvf dbgen.tar.gz --- Compile the code cd ./dbgen make -f makefile.suiteUse the TPC-H tool to generate 100 GB of test data. This operation takes about 30 minutes.
--- Change the directory to dbgen ./dbgen -s 100 -f
On the ECS instance, use the database connection tool provided by PolarDB (PolarDB-Tools) to connect to your cluster and import the test data into the
tpchdbtest database.Confirm that you are in the
dbgendirectory. The expected output is/<installation_path>/dbgen.--- Confirm the current directory pwdUse PolarDB-Tools to connect to the cluster from the command line.
/u01/polardb_pg_tools/bin/psql -h <cluster_endpoint> -p <port_for_cluster_endpoint> -U <privileged_account> -d tpchdbImport the test data.
\i ./dss.ddl \copy part from ./part.tbl with delimiter as '|' NULL ''; \copy region from ./region.tbl with delimiter as '|' NULL ''; \copy nation from ./nation.tbl with delimiter as '|' NULL ''; \copy orders from ./orders.tbl with delimiter as '|' NULL ''; \copy customer from ./customer.tbl with delimiter as '|' NULL ''; \copy lineitem from ./lineitem.tbl with delimiter as '|' NULL ''; \copy partsupp from ./partsupp.tbl with delimiter as '|' NULL ''; \copy supplier from ./supplier.tbl with delimiter as '|' NULL '';
Enable and create the columnstore index
Based on the version of your PolarDB for PostgreSQL cluster, enable the IMCI feature.
Create an IMCI for the test tables.
--partsupp table ALTER TABLE PARTSUPP ADD CONSTRAINT partsupp_pkey PRIMARY KEY (PS_PARTKEY, PS_SUPPKEY); CREATE INDEX imps ON partsupp USING csi(ps_partkey, ps_suppkey, ps_availqty, ps_supplycost, ps_comment); --part table ALTER TABLE PART ADD CONSTRAINT part_kpey PRIMARY KEY (P_PARTKEY); CREATE INDEX im_p ON part USING csi(p_partkey, p_name, p_mfgr, p_brand, p_type, p_size, p_container, p_retailprice, p_comment); --supplier table ALTER TABLE SUPPLIER ADD CONSTRAINT supplier_pkey PRIMARY KEY (S_SUPPKEY); CREATE INDEX im_s ON supplier USING csi(s_suppkey, s_name, s_address, s_nationkey, s_phone, s_acctbal, s_comment); --customer table ALTER TABLE CUSTOMER ADD CONSTRAINT customer_pkey PRIMARY KEY (C_CUSTKEY); CREATE INDEX im_c ON customer USING csi(c_custkey, c_name, c_address, c_nationkey, c_phone, c_acctbal, c_mktsegment, c_comment); --orders table ALTER TABLE ORDERS ADD CONSTRAINT orders_pkey PRIMARY KEY (O_ORDERKEY); CREATE INDEX im_o ON orders USING csi(o_orderkey, o_custkey, o_orderstatus, o_totalprice, o_orderdate, o_orderpriority, o_clerk, o_shippriority, o_comment); --lineitem table ALTER TABLE LINEITEM ADD CONSTRAINT lineitem_pkey PRIMARY KEY (L_ORDERKEY, L_LINENUMBER); CREATE INDEX im_l ON lineitem USING csi(l_orderkey, l_partkey, l_suppkey, l_linenumber, l_quantity, l_extendedprice, l_discount, l_tax, l_returnflag, l_linestatus, l_shipdate, l_commitdate, l_receiptdate, l_shipinstruct, l_shipmode, l_comment); --nation table ALTER TABLE NATION ADD CONSTRAINT nation_pkey PRIMARY KEY (N_NATIONKEY); CREATE INDEX im_n ON nation USING csi(n_nationkey, n_name, n_regionkey, n_comment); --region table ALTER TABLE REGION ADD CONSTRAINT region_pkey PRIMARY KEY (R_REGIONKEY); CREATE INDEX im_r ON region USING csi(r_regionkey, r_name, r_comment);Set the IMCI-related parameters for subsequent queries. For more information about the parameters, see Parameters.
SET polar_csi.enable_pk TO ON; SET polar_csi.enable_query TO ON; SET polar_csi.exec_parallel TO 32; SET polar_csi.cost_threshold TO 0; SET polar_csi.memory_limit TO 65536;
Execute SQL queries
In your PolarDB for PostgreSQL cluster, execute the 22 complex SQL queries and record their execution times.
You can use
\timingto record the total execution time of an SQL statement.\timingExecute the following SQL statements in order.
Query
SQL
Q1
EXPLAIN ANALYZE SELECT l_returnflag, l_linestatus, sum(l_quantity) as sum_qty, sum(l_extendedprice) as sum_base_price, sum(l_extendedprice * (1 - l_discount)) as sum_disc_price, sum(l_extendedprice * (1 - l_discount) * (1 + l_tax)) as sum_charge, avg(l_quantity) as avg_qty, avg(l_extendedprice) as avg_price, avg(l_discount) as avg_disc, count(*) as count_order FROM lineitem WHERE l_shipdate <= date '1998-12-01' - '60 day'::interval GROUP BY l_returnflag, l_linestatus ORDER BY l_returnflag, l_linestatus;Q2
EXPLAIN ANALYZE SELECT s_acctbal, s_name, n_name, p_partkey, p_mfgr, s_address, s_phone, s_comment FROM part, supplier, partsupp, nation, region WHERE p_partkey = ps_partkey and s_suppkey = ps_suppkey and p_size = 43 and p_type like '%NICKEL' and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'MIDDLE EAST' and ps_supplycost = ( SELECT min(ps_supplycost) FROM partsupp, supplier, nation, region WHERE p_partkey = ps_partkey and s_suppkey = ps_suppkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'MIDDLE EAST' ) ORDER BY s_acctbal desc, n_name, s_name, p_partkey limit 100;Q3
EXPLAIN ANALYZE SELECT l_orderkey, sum(l_extendedprice * (1 - l_discount)) as revenue, o_orderdate, o_shippriority FROM customer, orders, lineitem WHERE c_mktsegment = 'FURNITURE' and c_custkey = o_custkey and l_orderkey = o_orderkey and o_orderdate < date '1995-03-05' and l_shipdate > date '1995-03-05' GROUP BY l_orderkey, o_orderdate, o_shippriority ORDER BY revenue desc, o_orderdate limit 100;Q4
EXPLAIN ANALYZE SELECT o_orderpriority, count(*) as order_count FROM orders WHERE o_orderdate >= date '1993-05-01' and o_orderdate < date '1993-05-01' + interval '3 month'::interval and exists ( SELECT * FROM lineitem WHERE l_orderkey = o_orderkey and l_commitdate < l_receiptdate ) GROUP BY o_orderpriority ORDER BY o_orderpriority;Q5
EXPLAIN ANALYZE SELECT n_name, sum(l_extendedprice * (1 - l_discount)) as revenue FROM customer, orders, lineitem, supplier, nation, region WHERE c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'MIDDLE EAST' and o_orderdate >= date '1995-01-01' and o_orderdate < date '1995-01-01' + '1 year'::interval GROUP BY n_name ORDER BY revenue desc;Q6
EXPLAIN ANALYZE SELECT sum(l_extendedprice * l_discount) as revenue FROM lineitem WHERE l_shipdate >= date '1993-01-01' and l_shipdate < date '1993-01-01' + '1 year'::interval and l_discount between 0.03 - 0.01 and 0.03 + 0.01 and l_quantity < 24;Q7
EXPLAIN ANALYZE SELECT supp_nation, cust_nation, l_year, sum(volume) AS revenue FROM ( SELECT n1.n_name AS supp_nation, n2.n_name AS cust_nation, extract(year FROM l_shipdate) AS l_year, l_extendedprice * (1 - l_discount) AS volume FROM supplier, lineitem, orders, customer, nation n1, nation n2 WHERE s_suppkey = l_suppkey AND o_orderkey = l_orderkey AND c_custkey = o_custkey AND s_nationkey = n1.n_nationkey AND c_nationkey = n2.n_nationkey AND ((n1.n_name = 'FRANCE' AND n2.n_name = 'GERMANY') OR (n1.n_name = 'GERMANY' AND n2.n_name = 'FRANCE')) AND l_shipdate BETWEEN CAST('1995-01-01' AS date) AND CAST('1996-12-31' AS date)) AS shipping GROUP BY supp_nation, cust_nation, l_year ORDER BY supp_nation, cust_nation, l_year;Q8
EXPLAIN ANALYZE SELECT o_year, sum(case when nation = 'INDONESIA' then volume else 0 end) / sum(volume) as mkt_share FROM ( SELECT extract(year from o_orderdate) as o_year, l_extendedprice * (1 - l_discount) as volume, n2.n_name as nation FROM part, supplier, lineitem, orders, customer, nation n1, nation n2, region WHERE p_partkey = l_partkey and s_suppkey = l_suppkey and l_orderkey = o_orderkey and o_custkey = c_custkey and c_nationkey = n1.n_nationkey and n1.n_regionkey = r_regionkey and r_name = 'ASIA' and s_nationkey = n2.n_nationkey and o_orderdate between '1995-01-01'::date and '1996-12-31'::date and p_type = 'PROMO POLISHED NICKEL' ) as all_nations GROUP BY o_year ORDER BY o_year;Q9
EXPLAIN ANALYZE SELECT nation, o_year, sum(amount) as sum_profit FROM ( SELECT n_name as nation, extract(year from o_orderdate) as o_year, l_extendedprice * (1 - l_discount) - ps_supplycost * l_quantity as amount FROM part, supplier, lineitem, partsupp, orders, nation WHERE s_suppkey = l_suppkey and ps_suppkey = l_suppkey and ps_partkey = l_partkey and p_partkey = l_partkey and o_orderkey = l_orderkey and s_nationkey = n_nationkey and p_name like '%navajo%' ) as profit GROUP BY nation, o_year ORDER BY nation, o_year desc limit 100;Q10
EXPLAIN ANALYZE SELECT c_custkey, c_name, sum(l_extendedprice * (1 - l_discount)) as revenue, c_acctbal, n_name, c_address, c_phone, c_comment FROM customer, orders, lineitem, nation WHERE c_custkey = o_custkey and l_orderkey = o_orderkey and o_orderdate >= date '1993-08-01' and o_orderdate < date '1993-08-01' + '3 month'::interval and l_returnflag = 'R' and c_nationkey = n_nationkey GROUP BY c_custkey, c_name, c_acctbal, c_phone, n_name, c_address, c_comment ORDER BY revenue desc LIMIT 20;Q11
EXPLAIN ANALYZE SELECT ps_partkey, sum(ps_supplycost * ps_availqty) as value FROM partsupp, supplier, nation WHERE ps_suppkey = s_suppkey and s_nationkey = n_nationkey and n_name = 'ALGERIA' GROUP BY ps_partkey having sum(ps_supplycost * ps_availqty) > ( SELECT sum(ps_supplycost * ps_availqty) * 0.0001000000 FROM partsupp, supplier, nation WHERE ps_suppkey = s_suppkey and s_nationkey = n_nationkey and n_name = 'ALGERIA' ) ORDER BY value desc;Q12
EXPLAIN ANALYZE SELECT l_shipmode, sum(case when o_orderpriority = '1-URGENT' or o_orderpriority = '2-HIGH' then 1 else 0 end) as high_line_count, sum(case when o_orderpriority <> '1-URGENT' and o_orderpriority <> '2-HIGH' then 1 else 0 end) as low_line_count FROM orders, lineitem WHERE o_orderkey = l_orderkey and l_shipmode in ('AIR', 'FOB') and l_commitdate < l_receiptdate and l_shipdate < l_commitdate and l_receiptdate >= date '1996-01-01' and l_receiptdate < date '1996-01-01' + '1 year'::interval GROUP BY l_shipmode ORDER BY l_shipmode;Q13
EXPLAIN ANALYZE SELECT c_count, count(*) as custdist FROM ( SELECT c_custkey, count(o_orderkey) FROM customer left outer join orders on c_custkey = o_custkey and o_comment not like '%pending%requests%' GROUP BY c_custkey ) as c_orders (c_custkey, c_count) GROUP BY c_count ORDER BY custdist desc, c_count desc;Q14
EXPLAIN ANALYZE SELECT 100.00 * sum(case when p_type like 'PROMO%' then l_extendedprice * (1 - l_discount) else 0 end) / sum(l_extendedprice * (1 - l_discount)) as promo_revenue FROM lineitem, part WHERE l_partkey = p_partkey and l_shipdate >= date '1995-02-01' and l_shipdate < date '1995-02-01' + interval '1 month'::interval;Q15
EXPLAIN ANALYZE WITH revenue0 as ( SELECT l_suppkey as supplier_no, sum(l_extendedprice * (1 - l_discount)) as total_revenue FROM lineitem WHERE l_shipdate >= date '1995-08-01' and l_shipdate < date '1995-08-01' + '3 month'::interval GROUP BY l_suppkey) SELECT s_suppkey, s_name, s_address, s_phone, total_revenue FROM supplier, revenue0 WHERE s_suppkey = supplier_no and total_revenue = ( SELECT max(total_revenue) FROM revenue0 ) ORDER BY s_suppkey;Q16
EXPLAIN ANALYZE SELECT p_brand, p_type, p_size, count(distinct ps_suppkey) as supplier_cnt FROM partsupp, part WHERE p_partkey = ps_partkey and p_brand <> 'Brand#13' and p_type not like 'ECONOMY BRUSHED%' and p_size in (11, 8, 10, 31, 21, 13, 32, 28) and ps_suppkey not in ( SELECT s_suppkey FROM supplier WHERE s_comment like '%Customer%Complaints%' ) GROUP BY p_brand, p_type, p_size ORDER BY supplier_cnt desc, p_brand, p_type, p_size limit 100;Q17
EXPLAIN ANALYZE SELECT sum(l_extendedprice) / 7.0 as avg_yearly FROM lineitem, part where p_partkey = l_partkey and p_brand = 'Brand#44' and p_container = 'MED PKG' and l_quantity < ( SELECT 0.2 * avg(l_quantity) FROM lineitem WHERE l_partkey = p_partkey );Q18
EXPLAIN ANALYZE SELECT c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice, sum(l_quantity) FROM customer, orders, lineitem WHERE o_orderkey in ( SELECT l_orderkey FROM lineitem GROUP BY l_orderkey having sum(l_quantity) > 313 ) and c_custkey = o_custkey and o_orderkey = l_orderkey GROUP BY c_name, c_custkey, o_orderkey, o_orderdate, o_totalprice ORDER BY o_totalprice desc, o_orderdate limit 100; --LIMIT 100Q19
EXPLAIN ANALYZE SELECT sum(l_extendedprice* (1 - l_discount)) as revenue FROM lineitem, part WHERE ( p_partkey = l_partkey and p_brand = 'Brand#15' and p_container in ('SM CASE', 'SM BOX', 'SM PACK', 'SM PKG') and l_quantity >= 10 and l_quantity <= 10 + 10 and p_size between 1 and 5 and l_shipmode in ('AIR', 'AIR REG') and l_shipinstruct = 'DELIVER IN PERSON' ) or ( p_partkey = l_partkey and p_brand = 'Brand#45' and p_container in ('MED BAG', 'MED BOX', 'MED PKG', 'MED PACK') and l_quantity >= 18 and l_quantity <= 18 + 10 and p_size between 1 and 10 and l_shipmode in ('AIR', 'AIR REG') and l_shipinstruct = 'DELIVER IN PERSON' ) or ( p_partkey = l_partkey and p_brand = 'Brand#21' and p_container in ('LG CASE', 'LG BOX', 'LG PACK', 'LG PKG') and l_quantity >= 30 and l_quantity <= 30 + 10 and p_size between 1 and 15 and l_shipmode in ('AIR', 'AIR REG') and l_shipinstruct = 'DELIVER IN PERSON' ); --LIMIT -1Q20
EXPLAIN ANALYZE SELECT s_name, s_address FROM supplier, nation WHERE s_suppkey in ( SELECT ps_suppkey FROM partsupp WHERE ps_partkey in ( SELECT p_partkey FROM part WHERE p_name like 'lemon%' ) AND ps_availqty > ( SELECT 0.5 * sum(l_quantity) FROM lineitem WHERE l_partkey = ps_partkey and l_suppkey = ps_suppkey and l_shipdate >= date '1997-01-01' and l_shipdate < date '1997-01-01' + '1 year'::interval ) ) and s_nationkey = n_nationkey and n_name = 'INDONESIA' ORDER BY s_name limit 100;Q21
EXPLAIN ANALYZE SELECT s_name, count(*) as numwait FROM supplier, lineitem l1, orders, nation WHERE s_suppkey = l1.l_suppkey and o_orderkey = l1.l_orderkey and o_orderstatus = 'F' and l1.l_receiptdate > l1.l_commitdate and exists ( SELECT * FROM lineitem l2 WHERE l2.l_orderkey = l1.l_orderkey and l2.l_suppkey <> l1.l_suppkey ) and not exists ( SELECT * FROM lineitem l3 WHERE l3.l_orderkey = l1.l_orderkey and l3.l_suppkey <> l1.l_suppkey and l3.l_receiptdate > l3.l_commitdate ) and s_nationkey = n_nationkey and n_name = 'INDIA' GROUP BY s_name ORDER BY numwait desc, s_name limit 100; --LIMIT 100Q22
EXPLAIN ANALYZE SELECT cntrycode, count(*) as numcust, sum(c_acctbal) as totacctbal FROM ( SELECT substring(c_phone from 1 for 2) as cntrycode, c_acctbal FROM customer WHERE substring(c_phone from 1 for 2) in ('16', '17', '24', '21', '19', '22', '15') and c_acctbal > ( SELECT avg(c_acctbal) FROM customer WHERE c_acctbal > 0.00 and substring(c_phone from 1 for 2) in ('16', '17', '24', '21', '19', '22', '15') ) and not exists ( SELECT * FROM orders WHERE o_custkey = c_custkey ) ) as custsale GROUP BY cntrycode ORDER BY cntrycode; --LIMIT -1
Test results
Time consumed to create the columnstore index
Conclusion: Single-threaded serial creation takes a total of 39 minutes.
Storage space occupied by the columnstore index
Conclusion:
The heap table in the row store engine uses 126 GB of storage space.
Columnstore index space usage:
If the primary key is not included (that is,
polar_csi.enable_pk=false), the IMCI uses a total of 25 GB of storage space, which is 20% of the storage space used by the heap table in the row store engine. This mode is suitable for creating an IMCI for static data.If the primary key is included (that is,
polar_csi.enable_pk=true), the IMCI uses a total of 53 GB of storage space, which is 42% of the storage space used by the heap table in the row store engine. This mode is suitable for creating an IMCI for dynamic data.
Table name
Number of rows in the table
PostgreSQL row store
Columnstore index (excluding primary key)
IMCI (with primary key)
LINEITEM
600,037,902
86 GB
17 GB
36 GB
ORDERS
150,000,000
20 GB
4406 MB
9052 MB
PARTSUPP
80,000,000
13 GB
3452 MB
6689 MB
PART
20,000,000
3204 MB
487 MB
634 MB
CUSTOMER
15,000,000
2808 MB
992 MB
1108 MB
SUPPLIER
1,000,000
176 MB
63 MB
72 MB
NATION
25
8 KB
528 KB
528 KB
REGION
5
8 KB
528 KB
528 KB
Total
866,037,932
126 GB
25 GB
53 GB
Query performance
Conclusion:
Total execution time with IMCI: 23.92 seconds.
Total execution time with the row store engine: 2363.7 seconds (Q15 timed out and is calculated as 500 seconds).
In conclusion, IMCI performs nearly 100 times faster than the row store engine.
Query | Time consumed by IMCI (seconds) | Time consumed by PostgreSQL row store engine (seconds) | Speedup ratio (times) |
Q1 | 0.98 | 41.629 | 42.48 |
Q2 | 0.23 | 78.402 | 340.88 |
Q3 | 0.88 | 18.376 | 20.88 |
Q4 | 0.78 | 3.929 | 5.04 |
Q5 | 0.89 | 14.801 | 16.63 |
Q6 | 0.27 | 4.782 | 17.71 |
Q7 | 0.86 | 17.661 | 20.54 |
Q8 | 0.71 | 21.952 | 30.92 |
Q9 | 3.77 | 362.42 | 96.13 |
Q10 | 1.41 | 18.313 | 12.99 |
Q11 | 0.15 | 8.307 | 55.38 |
Q12 | 0.61 | 7.146 | 11.71 |
Q13 | 2.31 | 308.555 | 133.57 |
Q14 | 0.67 | 10.658 | 15.91 |
Q15 | 0.44 | Timed out, calculated as 500 | 1136.36 |
Q16 | 0.44 | 71.062 | 161.50 |
Q17 | 0.84 | 288 | 342.86 |
Q18 | 2.58 | 473.446 | 183.51 |
Q19 | 1.42 | 0.416 | 0.29 |
Q20 | 0.54 | 83 | 153.70 |
Q21 | 2.68 | 17.387 | 6.49 |
Q22 | 0.46 | 13.458 | 29.26 |
Summary | 23.92 | 2363.7 | 98.82 |
