Merge branch 'nik-improve-l003' into 'master'

L003: do not analyze multi-columns PKs, fix JSON syntax

See merge request postgres-ai/postgres-checkup!448

Author: NikolayS

resources/checks/L003_integer_in_pk.sh

@@ -1,5 +1,5 @@
 if [[ ! -z ${IS_LARGE_DB+x} ]] && [[ ${IS_LARGE_DB} == "1" ]]; then
-  MIN_RELPAGES=1000
+  MIN_RELPAGES=100
 else
   MIN_RELPAGES=0
 fi
@@ -10,11 +10,14 @@ f_stderr=$(mktemp)
 (${CHECK_HOST_CMD} "${_PSQL} -f - " <<SQL
 do \$$
 declare
+  MIN_RELPAGES int8 = ${MIN_RELPAGES}; -- skip tables with small number of pages
   rec record;
   out text;
+  out1 json;
   i numeric;
   val int8;
   ratio numeric;
+  sql text;
 begin
   out := '';
   i := 0;
@@ -25,8 +28,8 @@ begin
       nspname as schema_name,
       relname as table_name,
       t.typname,
-      attname,
-      (select pg_get_serial_sequence(quote_ident(nspname) || '.' || quote_ident(relname), attname)) as seq
+      (select pg_get_serial_sequence(quote_ident(nspname) || '.' || quote_ident(relname), attname)) as seq,
+      min(attname) as attname
     from pg_index i
     join pg_class c on c.oid = i.indrelid
     left join pg_namespace n on n.oid = c.relnamespace
@@ -36,25 +39,35 @@ begin
     join pg_type t on t.oid = atttypid
     where
       i.indisprimary
-      and (c.relpages > ${MIN_RELPAGES} or (select pg_get_serial_sequence(quote_ident(nspname) || '.' || quote_ident(relname), attname)) is not null)
+      and (c.relpages > MIN_RELPAGES or (select pg_get_serial_sequence(quote_ident(nspname) || '.' || quote_ident(relname), attname)) is not null)
       and t.typname in ('int2', 'int4')
       and nspname <> 'pg_toast'
+      group by 1, 2, 3, 4, 5, 6
+      having count(*) = 1 -- skip PKs with 2+ columns
   loop
+    raise debug 'table: %', rec.table_name;
+
     if rec.seq is null then
-        execute format('select max(%I) from %I.%I;', rec.attname, rec.schema_name, rec.table_name) into val;
+        sql := format('select max(%I) from %I.%I;', rec.attname, rec.schema_name, rec.table_name);
     else
-        execute format('SELECT last_value FROM %s;', rec.seq) into val;
+        sql := format('select last_value from %s;', rec.seq);
     end if;
+
+    raise debug 'sql: %', sql;
+    execute sql into val;
+
     if rec.typname = 'int4' then
       ratio := (val::numeric / 2^31)::numeric;
     elsif rec.typname = 'int2' then
       ratio := (val::numeric / 2^15)::numeric;
     else
       assert false, 'unreachable point';
     end if;
+
     if ratio > 0.1 then -- report only if > 10% of capacity is reached
       i := i + 1;
-      out := out || '{"' || rec.table_name || '":' || json_build_object(
+
+      out1 := json_build_object(
           'table',
           coalesce(nullif(quote_ident(rec.schema_name), 'public') || '.', '') || quote_ident(rec.table_name),
           'pk',
@@ -65,9 +78,18 @@ begin
           val,
           'capacity_used_percent',
           round(100 * ratio, 2)
-      ) || '}';
+      );
+
+      raise debug 'cur: %', out1;
+
+      if out <> '' then out := out || ', '; end if;
+
+      out := out || '"' || rec.table_name || '":' || out1 || '';
     end if;
   end loop;
+
+  out := '{' || out || '}';
+
   raise info '%', out;
 end;
 \$$ language plpgsql;