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configuration.sql
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@plcplc
plcplc committed Oct 17, 2023
1 parent 6b00732 commit 454b1b2
Showing 1 changed file with 222 additions and 5 deletions.
227 changes: 222 additions & 5 deletions crates/connectors/ndc-postgres/src/configuration.sql
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Original file line number Diff line number Diff line change
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-- query with arguments set.

-- DEALLOCATE ALL; -- Or use 'DEALLOCATE configuration' between reloads
-- PREPARE configuration(varchar[]) AS
-- PREPARE configuration(varchar[], jsonb) AS

WITH
-- The overall structure of this query is a CTE (i.e. 'WITH .. SELECT')
-- statement which define projections of the catalog tables into forms that are
Expand Down Expand Up @@ -227,9 +228,10 @@ WITH
)
),

-- Aggregate functions are recorded in 'pg_proc', see
-- https://www.postgresql.org/docs/current/catalog-pg-proc.html for its
-- schema.
-- Aggregate functions are recorded across 'pg_proc' and 'pg_aggregate', see
-- https://www.postgresql.org/docs/current/catalog-pg-proc.html and
-- https://www.postgresql.org/docs/current/catalog-pg-aggregate.html for
-- their schema.
aggregates AS
(
WITH
Expand Down Expand Up @@ -302,6 +304,131 @@ WITH

),

-- Operators are recorded across 'pg_proc', pg_operator, and 'pg_aggregate', see
-- https://www.postgresql.org/docs/current/catalog-pg-proc.html,
-- https://www.postgresql.org/docs/current/catalog-pg-operator.html and
-- https://www.postgresql.org/docs/current/catalog-pg-aggregate.html for
-- their schema.
--
-- In Postgres, operators and aggregation function functions each relate to a
-- pg_proc procedures. On CockroachDB, however, they are independent.
comparison_operators AS
(
SELECT
op.oprname AS operator_name,
t1.type_name AS argument1_type,
t2.type_name AS argument2_type
FROM
pg_operator
AS op
INNER JOIN
types
AS t1
ON (op.oprleft = t1.type_id)
INNER JOIN
types
AS t2
ON (op.oprright = t2.type_id)
INNER JOIN
types
AS t_res
ON (op.oprresult = t_res.type_id)
WHERE
t_res.type_name = 'bool'
ORDER BY op.oprname
),

implicit_casts AS
(
SELECT
t_from.type_name as from_type,
t_to.type_name as to_type
FROM
pg_cast
INNER JOIN
types
AS t_from
ON (t_from.type_id = pg_cast.castsource)
INNER JOIN
types
AS t_to
ON (t_to.type_id = pg_cast.casttarget)
WHERE
pg_cast.castcontext = 'i'
),

-- Some comparison operators are not defined explicitly for every type they would be
-- valid for, relying instead on implicit casts to extend the types they can apply to.
--
-- Examples:
--
-- Postgres only defines 'like' for 'text', not for 'varchar'. But there's
-- an implicit cast for varchar->text.
--
-- CockroachDB does not define any comparison operators for 'float4', but
-- for 'float8', along with an implict cast for float4->float8.
--
-- To make comparison operators available to all those types as well we
-- extend our set of operators to include implicit casts.
comparison_operators_cast_extended AS
(
-- The left argument could have been cast.
SELECT
op.operator_name,
cast1.from_type as argument1_type,
op.argument2_type
FROM
comparison_operators
AS op
INNER JOIN
implicit_casts
AS cast1
ON (cast1.to_type = op.argument1_type)
UNION
-- The right argument could have been cast.
SELECT
op.operator_name,
op.argument1_type,
cast2.from_type as argument2_type
FROM
comparison_operators
AS op
INNER JOIN
implicit_casts
AS cast2
ON (cast2.to_type = op.argument2_type)
UNION
-- Both arguments could have been cast.
SELECT
op.operator_name,
cast1.from_type as argument1_type,
cast2.from_type as argument2_type
FROM
comparison_operators
AS op
INNER JOIN
implicit_casts
AS cast1
ON (cast1.to_type = op.argument1_type)
INNER JOIN
implicit_casts
AS cast2
ON (cast2.to_type = op.argument2_type)
UNION
-- Neither argument could have been cast.
SELECT * FROM comparison_operators
),

-- The names that comparison operators are exposed under is configurable.
operator_mappings AS
(
SELECT
v ->> 'operatorName' AS operator_name,
v ->> 'alias' AS alias
FROM
jsonb_array_elements($2) AS v
),

-- Constraints are recorded in 'pg_constraint', see
-- https://www.postgresql.org/docs/current/catalog-pg-constraint.html for its
-- schema.
Expand Down Expand Up @@ -411,7 +538,8 @@ WITH
)
SELECT
coalesce(tables.result, '{}'::jsonb) AS "Tables",
coalesce(aggregate_functions.result, '{}'::jsonb) AS "AggregateFunctions"
coalesce(aggregate_functions.result, '{}'::jsonb) AS "AggregateFunctions",
coalesce(comparison_functions.result, '{}'::jsonb) as "ComparisonFunctions"
FROM
(
-- Tables and views
Expand Down Expand Up @@ -616,3 +744,92 @@ FROM
GROUP BY agg.argument_type
) AS agg
) AS aggregate_functions

CROSS JOIN
(
-- Comparison Operators
WITH
comparison_operators_mapped AS
(
SELECT
map.alias as mapped_name,
op.operator_name,
op.argument1_type,
op.argument2_type
FROM
comparison_operators_cast_extended
AS op
INNER JOIN
operator_mappings
AS map
USING (operator_name)
),

-- When an operator is overloaded for a type (either explicitly or
-- through implict casts), prefer the version where both arguments are
-- the same type.
comparison_operators_filtered AS
(
SELECT DISTINCT ON (op.mapped_name, op.argument1_type)
op.mapped_name,
op.operator_name,
op.argument1_type,
op.argument2_type
FROM
comparison_operators_mapped
AS op
ORDER BY
op.mapped_name,
op.argument1_type,
op.argument1_type = op.argument2_type DESC
),

comparison_operators_by_first_arg AS
(
SELECT
op.argument1_type,
jsonb_object_agg(
op.mapped_name,
jsonb_build_object(
'operatorName', op.operator_name,
'argumentType', op.argument2_type
)
)
AS result
FROM
comparison_operators_filtered
AS op
GROUP BY op.argument1_type
)
SELECT
jsonb_object_agg(
op.argument1_type,
op.result
) as result
FROM
comparison_operators_by_first_arg
AS op
) AS comparison_functions;

-- Uncomment the following lines to just run the configuration query with reasonable default arguments
--
-- EXECUTE configuration(
-- '{"information_schema", "tiger"}'::varchar[],
-- '[
-- {"operatorName": "=", "alias": "_eq"},
-- {"operatorName": "!=", "alias": "_neq"},
-- {"operatorName": "<>", "alias": "_neq"},
-- {"operatorName": "<=", "alias": "_lte"},
-- {"operatorName": ">", "alias": "_gt"},
-- {"operatorName": ">=", "alias": "_gte"},
-- {"operatorName": "<", "alias": "_lt"},
-- {"operatorName": "~~", "alias": "_like"},
-- {"operatorName": "!~~", "alias": "_nlike"},
-- {"operatorName": "~~*", "alias": "_ilike"},
-- {"operatorName": "!~~*", "alias": "_nilike"},
-- {"operatorName": "~", "alias": "_regex"},
-- {"operatorName": "!~", "alias": "_nregex"},
-- {"operatorName": "~*", "alias": "_iregex"},
-- {"operatorName": "!~*", "alias": "_niregex"}
-- ]'::jsonb
-- );

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