Contents

• pg_roaringbitmap
• Introduction
• Build
  • Requirements
  • Build
  • Test
• Build on PostgreSQL 9.x or Greenplum 6.0
  • Build
  • Test
• Usage
  • about roaringbitmap data type
  • input and ouput
  • Use bitmap as type of column
  • Build bitmap from integers
  • Bitmap Calculation (OR, AND, XOR, ANDNOT)
  • Bitmap Aggregate (OR, AND, XOR, BUILD)
  • Calculate cardinality
  • Convert bitmap to integer array
  • Convert bitmap to SET of integers
  • Opperator List
  • Function List
  • Aggregation List
• Cloud Vendor Support

pg_roaringbitmap

RoaringBitmap extension for PostgreSQL.

It's initial based on https://github.com/zeromax007/gpdb-roaringbitmap.

Introduction

Roaring bitmaps are compressed bitmaps which tend to outperform conventional compressed bitmaps such as WAH, EWAH or Concise. In some instances, roaring bitmaps can be hundreds of times faster and they often offer significantly better compression. They can even be faster than uncompressed bitmaps. More information https://github.com/RoaringBitmap/CRoaring .

Build

Requirements

• PostgreSQL 10+
• Other Requirements from https://github.com/RoaringBitmap/CRoaring

Build

su - postgres
make
sudo make install
psql -c "create extension roaringbitmap"

Note:You can use make -f Makefile_native instead ofmake to let the compiler use the SIMD instructions if it's supported by your CPU. In some scenarios, it may double the performance. But if you copy the pg_roaringbitmap binary which builded on machine with SIMD support to other machine without SIMD and run, you could get a SIGILL crash.

Test

make installcheck

Build on PostgreSQL 9.x or Greenplum 6.0

Parallel execution is not supported in PostgreSQL 9.5 and earlier. If you want to compile on these early PostgreSQL versions or Greenplum 6.0(based on PostgreSQL 9.4), you need to remove the PARALLEL keyword from these SQL files.

cd pg_roaringbitmap
sed 's/PARALLEL SAFE//g' -i roaringbitmap--*.sql
sed -z 's/,[ \r\n]*PARALLEL = SAFE//g' -i roaringbitmap--*.sql

Then refer to [Build] above for building, such as the steps to build on Greenplum 6.0:

Build

su - gpadmin
make
make install
psql -c "create extension roaringbitmap"

Test

sudo yum install 'perl(Data::Dumper)'
make installcheck

Since the expected output is based on PostgreSQL 10+, this test will not pass. Check the difference in the output file. If the execution results are the same, only the execution plan or other content that is not related to pg_roaringbitmap` is different, the test can be considered OK.

diff results/roaringbitmap.out expected/roaringbitmap_gpdb6.out

Usage

about roaringbitmap data type

Logically, you could think of roaringbitmap data type as bit(4294967296), and it should be noted that the integers added to bitmaps is considered to be unsigned. Within bitmaps, numbers are ordered according to uint32. We order the numbers like 0, 1, ..., 2147483647, -2147483648, -2147483647,..., -1. But we use bigint to reference the range of these integers, that is [0 4294967296).

input and ouput

Support two kind of input/output syntax 'array' and 'bytea', The default output format is 'bytea'.

postgres=# select roaringbitmap('{1,100,10}');
                 roaringbitmap
------------------------------------------------
 \x3a30000001000000000002001000000001000a006400
(1 row)

or

postgres=# select '\x3a30000001000000000002001000000001000a006400'::roaringbitmap;
                 roaringbitmap
------------------------------------------------
 \x3a30000001000000000002001000000001000a006400
(1 row)

output format can changed by roaringbitmap.output_format

postgres=# set roaringbitmap.output_format='bytea';
SET
postgres=# select '{1}'::roaringbitmap;
             roaringbitmap
----------------------------------------
 \x3a3000000100000000000000100000000100
(1 row)

postgres=# set roaringbitmap.output_format='array';
SET
postgres=# select '{1}'::roaringbitmap;
 roaringbitmap
---------------
 {1}
(1 row)

Use bitmap as type of column

CREATE TABLE t1 (id integer, bitmap roaringbitmap);

Build bitmap from integers

INSERT INTO t1 SELECT 1,rb_build(ARRAY[1,2,3,4,5,6,7,8,9,200]);

INSERT INTO t1 SELECT 2,rb_build_agg(e) FROM generate_series(1,100) e;

Bitmap Calculation (OR, AND, XOR, ANDNOT)

SELECT roaringbitmap('{1,2,3}') | roaringbitmap('{3,4,5}');
SELECT roaringbitmap('{1,2,3}') & roaringbitmap('{3,4,5}');
SELECT roaringbitmap('{1,2,3}') # roaringbitmap('{3,4,5}');
SELECT roaringbitmap('{1,2,3}') - roaringbitmap('{3,4,5}');

Bitmap Aggregate (OR, AND, XOR, BUILD)

SELECT rb_or_agg(bitmap) FROM t1;
SELECT rb_and_agg(bitmap) FROM t1;
SELECT rb_xor_agg(bitmap) FROM t1;
SELECT rb_build_agg(e) FROM generate_series(1,100) e;

Calculate cardinality

SELECT rb_cardinality('{1,2,3}');

Convert bitmap to integer array

SELECT rb_to_array(bitmap) FROM t1 WHERE id = 1;

Convert bitmap to SET of integers

SELECT unnest(rb_to_array('{1,2,3}'::roaringbitmap));

or

SELECT rb_iterate('{1,2,3}'::roaringbitmap);

Opperator List

Function List

rb_iterate(roaringbitmap('{1,2,3}'))

1
2
3

Aggregation List

select rb_build_agg(id)
    from (values (1),(2),(3)) t(id)

select rb_or_agg(bitmap)
    from (values (roaringbitmap('{1,2,3}')),
                 (roaringbitmap('{2,3,4}'))
          ) t(bitmap)

select rb_and_agg(bitmap)
    from (values (roaringbitmap('{1,2,3}')),
                 (roaringbitmap('{2,3,4}'))
          ) t(bitmap)

select rb_xor_agg(bitmap)
    from (values (roaringbitmap('{1,2,3}')),
                 (roaringbitmap('{2,3,4}'))
          ) t(bitmap)

select rb_or_cardinality_agg(bitmap)
    from (values (roaringbitmap('{1,2,3}')),
                 (roaringbitmap('{2,3,4}'))
          ) t(bitmap)

select rb_and_cardinality_agg(bitmap)
    from (values (roaringbitmap('{1,2,3}')),
                 (roaringbitmap('{2,3,4}'))
          ) t(bitmap)

select rb_xor_cardinality_agg(bitmap)
    from (values (roaringbitmap('{1,2,3}')),
                 (roaringbitmap('{2,3,4}'))
          ) t(bitmap)

Cloud Vendor Support

pg_roaringbitmap is supported by the following cloud vendors

• Alibaba Cloud RDS PostgreSQL: https://www.alibabacloud.com/help/doc-detail/142340.htm
• Huawei Cloud RDS PostgreSQL: https://support.huaweicloud.com/usermanual-rds/rds_09_0045.html
• Tencent Cloud RDS PostgreSQL: https://cloud.tencent.com/document/product/409/67299

To request support for pg_roaringbitmap from other cloud vendors, please see the following:

• Amazon RDS: send an email to rds-postgres-extensions-request@amazon.com with the extension name and use case (docs)
• Google Cloud SQL: comment on this issue
• DigitalOcean Managed Databases: comment on this idea
• Azure Database for PostgreSQL: comment on this post