Merge pull request #4 from supabase/or/issue_1

Only consider indexes on primitive types

index_advisor--0.1.0--0.1.1.sql

@@ -0,0 +1,161 @@
+drop type index_advisor_output;
+
+create or replace function index_advisor(
+    query text
+)
+    returns table  (
+        startup_cost_before jsonb,
+        startup_cost_after jsonb,
+        total_cost_before jsonb,
+        total_cost_after jsonb,
+        index_statements text[]
+    )
+    volatile
+    language plpgsql
+    as $$
+declare
+    n_args int;
+    prepared_statement_name text = 'index_advisor_working_statement';
+    hypopg_schema_name text = (select extnamespace::regnamespace::text from pg_extension where extname = 'hypopg');
+    explain_plan_statement text;
+    rec record;
+    plan_initial jsonb;
+    plan_final jsonb;
+    statements text[] = '{}';
+begin
+
+    -- Disallow multiple statements
+    if query ilike '%;%' then
+        raise exception 'query must not contain a semicolon';
+    end if;
+
+    -- Hack to support PostgREST because the prepared statement for args incorrectly defaults to text
+    query := replace(query, 'WITH pgrst_payload AS (SELECT $1 AS json_data)', 'WITH pgrst_payload AS (SELECT $1::json AS json_data)');
+
+    -- Create a prepared statement for the given query
+    deallocate all;
+    execute format('prepare %I as %s', prepared_statement_name, query);
+
+    -- Detect how many arguments are present in the prepared statement
+    n_args = (
+        select
+            coalesce(array_length(parameter_types, 1), 0)
+        from
+            pg_prepared_statements
+        where
+            name = prepared_statement_name
+        limit
+            1
+    );
+
+    -- Create a SQL statement that can be executed to collect the explain plan
+    explain_plan_statement = format(
+        'set local plan_cache_mode = force_generic_plan; explain (format json) execute %I%s',
+        --'explain (format json) execute %I%s',
+        prepared_statement_name,
+        case
+            when n_args = 0 then ''
+            else format(
+                '(%s)', array_to_string(array_fill('null'::text, array[n_args]), ',')
+            )
+        end
+    );
+
+    -- Store the query plan before any new indexes
+    execute explain_plan_statement into plan_initial;
+
+    -- Create possible indexes
+    for rec in (
+        with extension_regclass as (
+            select
+                distinct objid as oid
+            from
+                pg_depend
+            where
+                deptype = 'e'
+        )
+        select
+            pc.relnamespace::regnamespace::text as schema_name,
+            pc.relname as table_name,
+            pa.attname as column_name,
+            format(
+                'select %I.hypopg_create_index($i$create index on %I.%I(%I)$i$)',
+                hypopg_schema_name,
+                pc.relnamespace::regnamespace::text,
+                pc.relname,
+                pa.attname
+            ) hypopg_statement
+        from
+            pg_catalog.pg_class pc
+            join pg_catalog.pg_attribute pa
+                on pc.oid = pa.attrelid
+            left join extension_regclass er
+                on pc.oid = er.oid
+            left join pg_index pi
+                on pc.oid = pi.indrelid
+                and (select array_agg(x) from unnest(pi.indkey) v(x)) = array[pa.attnum]
+                and pi.indexprs is null -- ignore expression indexes
+                and pi.indpred is null -- ignore partial indexes
+        where
+            pc.relnamespace::regnamespace::text not in ( -- ignore schema list
+                'pg_catalog', 'pg_toast', 'information_schema'
+            )
+            and er.oid is null -- ignore entities owned by extensions
+            and pc.relkind in ('r', 'm') -- regular tables, and materialized views
+            and pc.relpersistence = 'p' -- permanent tables (not unlogged or temporary)
+            and pa.attnum > 0
+            and not pa.attisdropped
+            and pi.indrelid is null
+            and pa.atttypid in (20,16,1082,1184,1114,701,23,21,700,1083,2950,1700,25,18,1042,1043)
+        )
+        loop
+            -- Create the hypothetical index
+            execute rec.hypopg_statement;
+        end loop;
+
+    /*
+    for rec in select * from hypopg()
+        loop
+            raise notice '%', rec;
+        end loop;
+    */
+
+    -- Create a prepared statement for the given query
+    -- The original prepared statement MUST be dropped because its plan is cached
+    execute format('deallocate %I', prepared_statement_name);
+    execute format('prepare %I as %s', prepared_statement_name, query);
+
+    -- Store the query plan after new indexes
+    execute explain_plan_statement into plan_final;
+
+    --raise notice '%', plan_final;
+
+    -- Idenfity referenced indexes in new plan
+    execute format(
+        'select
+            coalesce(array_agg(hypopg_get_indexdef(indexrelid) order by indrelid, indkey::text), $i${}$i$::text[])
+        from
+            %I.hypopg()
+        where
+            %s ilike ($i$%%$i$ || indexname || $i$%%$i$)
+        ',
+        hypopg_schema_name,
+        quote_literal(plan_final)::text
+    ) into statements;
+
+    -- Reset all hypothetical indexes
+    perform hypopg_reset();
+
+    -- Reset prepared statements
+    deallocate all;
+
+    return query values (
+        (plan_initial -> 0 -> 'Plan' -> 'Startup Cost'),
+        (plan_final -> 0 -> 'Plan' -> 'Startup Cost'),
+        (plan_initial -> 0 -> 'Plan' -> 'Total Cost'),
+        (plan_final -> 0 -> 'Plan' -> 'Total Cost'),
+        statements::text[]
+    );
+
+end;
+$$;

index_advisor--0.1.1.sql

@@ -0,0 +1,159 @@
+create or replace function index_advisor(
+    query text
+)
+    returns table  (
+        startup_cost_before jsonb,
+        startup_cost_after jsonb,
+        total_cost_before jsonb,
+        total_cost_after jsonb,
+        index_statements text[]
+    )
+    volatile
+    language plpgsql
+    as $$
+declare
+    n_args int;
+    prepared_statement_name text = 'index_advisor_working_statement';
+    hypopg_schema_name text = (select extnamespace::regnamespace::text from pg_extension where extname = 'hypopg');
+    explain_plan_statement text;
+    rec record;
+    plan_initial jsonb;
+    plan_final jsonb;
+    statements text[] = '{}';
+begin
+
+    -- Disallow multiple statements
+    if query ilike '%;%' then
+        raise exception 'query must not contain a semicolon';
+    end if;
+
+    -- Hack to support PostgREST because the prepared statement for args incorrectly defaults to text
+    query := replace(query, 'WITH pgrst_payload AS (SELECT $1 AS json_data)', 'WITH pgrst_payload AS (SELECT $1::json AS json_data)');
+
+    -- Create a prepared statement for the given query
+    deallocate all;
+    execute format('prepare %I as %s', prepared_statement_name, query);
+
+    -- Detect how many arguments are present in the prepared statement
+    n_args = (
+        select
+            coalesce(array_length(parameter_types, 1), 0)
+        from
+            pg_prepared_statements
+        where
+            name = prepared_statement_name
+        limit
+            1
+    );
+
+    -- Create a SQL statement that can be executed to collect the explain plan
+    explain_plan_statement = format(
+        'set local plan_cache_mode = force_generic_plan; explain (format json) execute %I%s',
+        --'explain (format json) execute %I%s',
+        prepared_statement_name,
+        case
+            when n_args = 0 then ''
+            else format(
+                '(%s)', array_to_string(array_fill('null'::text, array[n_args]), ',')
+            )
+        end
+    );
+
+    -- Store the query plan before any new indexes
+    execute explain_plan_statement into plan_initial;
+
+    -- Create possible indexes
+    for rec in (
+        with extension_regclass as (
+            select
+                distinct objid as oid
+            from
+                pg_depend
+            where
+                deptype = 'e'
+        )
+        select
+            pc.relnamespace::regnamespace::text as schema_name,
+            pc.relname as table_name,
+            pa.attname as column_name,
+            format(
+                'select %I.hypopg_create_index($i$create index on %I.%I(%I)$i$)',
+                hypopg_schema_name,
+                pc.relnamespace::regnamespace::text,
+                pc.relname,
+                pa.attname
+            ) hypopg_statement
+        from
+            pg_catalog.pg_class pc
+            join pg_catalog.pg_attribute pa
+                on pc.oid = pa.attrelid
+            left join extension_regclass er
+                on pc.oid = er.oid
+            left join pg_index pi
+                on pc.oid = pi.indrelid
+                and (select array_agg(x) from unnest(pi.indkey) v(x)) = array[pa.attnum]
+                and pi.indexprs is null -- ignore expression indexes
+                and pi.indpred is null -- ignore partial indexes
+        where
+            pc.relnamespace::regnamespace::text not in ( -- ignore schema list
+                'pg_catalog', 'pg_toast', 'information_schema'
+            )
+            and er.oid is null -- ignore entities owned by extensions
+            and pc.relkind in ('r', 'm') -- regular tables, and materialized views
+            and pc.relpersistence = 'p' -- permanent tables (not unlogged or temporary)
+            and pa.attnum > 0
+            and not pa.attisdropped
+            and pi.indrelid is null
+            and pa.atttypid in (20,16,1082,1184,1114,701,23,21,700,1083,2950,1700,25,18,1042,1043)
+        )
+        loop
+            -- Create the hypothetical index
+            execute rec.hypopg_statement;
+        end loop;
+
+    /*
+    for rec in select * from hypopg()
+        loop
+            raise notice '%', rec;
+        end loop;
+    */
+
+    -- Create a prepared statement for the given query
+    -- The original prepared statement MUST be dropped because its plan is cached
+    execute format('deallocate %I', prepared_statement_name);
+    execute format('prepare %I as %s', prepared_statement_name, query);
+
+    -- Store the query plan after new indexes
+    execute explain_plan_statement into plan_final;
+
+    --raise notice '%', plan_final;
+
+    -- Idenfity referenced indexes in new plan
+    execute format(
+        'select
+            coalesce(array_agg(hypopg_get_indexdef(indexrelid) order by indrelid, indkey::text), $i${}$i$::text[])
+        from
+            %I.hypopg()
+        where
+            %s ilike ($i$%%$i$ || indexname || $i$%%$i$)
+        ',
+        hypopg_schema_name,
+        quote_literal(plan_final)::text
+    ) into statements;
+
+    -- Reset all hypothetical indexes
+    perform hypopg_reset();
+
+    -- Reset prepared statements
+    deallocate all;
+
+    return query values (
+        (plan_initial -> 0 -> 'Plan' -> 'Startup Cost'),
+        (plan_final -> 0 -> 'Plan' -> 'Startup Cost'),
+        (plan_initial -> 0 -> 'Plan' -> 'Total Cost'),
+        (plan_final -> 0 -> 'Plan' -> 'Total Cost'),
+        statements::text[]
+    );
+
+end;
+$$;

index_advisor.control

@@ -1,4 +1,4 @@
 comment = 'Query index advisor'
-default_version = '0.1.0'
+default_version = '0.1.1'
 relocatable = true
 requires = hypopg

test/expected/disallow_semicolon.out

@@ -1,5 +1,5 @@
 begin;
-    create extension index_advisor cascade;
+    create extension index_advisor version '0.1.1' cascade;
 NOTICE:  installing required extension "hypopg"
     select index_advisor($$ select 1; $$);
 ERROR:  query must not contain a semicolon

test/expected/integration.out

@@ -1,5 +1,5 @@
 begin;
-    create extension index_advisor cascade;
+    create extension index_advisor version '0.1.1' cascade;
 NOTICE:  installing required extension "hypopg"
     create table public.book(
         id int,

test/expected/issue_1.out

@@ -0,0 +1,18 @@
+begin;
+    create extension index_advisor version '0.1.1' cascade;
+NOTICE:  installing required extension "hypopg"
+    create table public.book(
+        id int,
+        -- json type is not btree indexable. In version 0.1.1 this raises the error
+        -- ERROR:  data type json has no default operator class for access method "btree"
+        meta json
+    );
+    select index_advisor($$
+        select * from book where id = $1
+    $$);
+                                index_advisor                                 
+------------------------------------------------------------------------------
+ (0.00,4.07,25.88,13.54,"{""CREATE INDEX ON public.book USING btree (id)""}")
+(1 row)
+
+rollback;

test/expected/multi_index.out

@@ -1,5 +1,5 @@
 begin;
-    create extension index_advisor cascade;
+    create extension index_advisor version '0.1.1' cascade;
 NOTICE:  installing required extension "hypopg"
     create table author(
         id serial primary key,

test/expected/postgrest_query.out

@@ -1,5 +1,5 @@
 begin;
-    create extension index_advisor cascade;
+    create extension index_advisor version '0.1.1' cascade;
 NOTICE:  installing required extension "hypopg"
     create function get_info(x int) returns text language sql as $$ select 'foo' $$;
     select index_advisor($$

test/sql/disallow_semicolon.sql

@@ -1,6 +1,6 @@
 begin;
 
-    create extension index_advisor cascade;
+    create extension index_advisor version '0.1.1' cascade;
 
     select index_advisor($$ select 1; $$);
 

test/sql/integration.sql

@@ -1,6 +1,6 @@
 begin;
 
-    create extension index_advisor cascade;
+    create extension index_advisor version '0.1.1' cascade;
 
     create table public.book(
         id int,