Optimize GetRefs, correct and add indexes on ref table (#1284)

* Correct index on ref table, add path index for get refs optimization

* Fix gorm tags on ref table

* Fix typo

* fix goose migration tags

* add pg_trgm extension

code/go/0chain.net/blobbercore/reference/ref.go

@@ -34,8 +34,8 @@ type Ref struct {
 	Type                    string `gorm:"column:type;size:1" dirlist:"type" filelist:"type"`
 	AllocationID            string `gorm:"column:allocation_id;size:64;not null;index:idx_path_alloc,priority:1;index:idx_parent_path_alloc,priority:1;index:idx_validation_alloc,priority:1" dirlist:"allocation_id" filelist:"allocation_id"`
 	LookupHash              string `gorm:"column:lookup_hash;size:64;not null;index:idx_lookup_hash" dirlist:"lookup_hash" filelist:"lookup_hash"`
-	Name                    string `gorm:"column:name;size:100;not null;index:idx_name_gin:gin" dirlist:"name" filelist:"name"`
-	Path                    string `gorm:"column:path;size:1000;not null;index:idx_path_alloc,priority:2;index:path_idx" dirlist:"path" filelist:"path"`
+	Name                    string `gorm:"column:name;size:100;not null;index:idx_name_gin" dirlist:"name" filelist:"name"` // uses GIN tsvector index for full-text search
+	Path                    string `gorm:"column:path;size:1000;not null;index:idx_path_alloc,priority:2;index:path_idx;index:idx_path_gin_trgm" dirlist:"path" filelist:"path"`
 	FileMetaHash            string `gorm:"column:file_meta_hash;size:64;not null" dirlist:"file_meta_hash" filelist:"file_meta_hash"`
 	Hash                    string `gorm:"column:hash;size:64;not null" dirlist:"hash" filelist:"hash"`
 	NumBlocks               int64  `gorm:"column:num_of_blocks;not null;default:0" dirlist:"num_of_blocks" filelist:"num_of_blocks"`

code/go/0chain.net/swagger.md

@@ -12,7 +12,6 @@
 
 ## Content negotiation
 
-
 ### URI Schemes
   * http
   * https

goose/migrations/002_correct_and_add_indexes.sql

@@ -0,0 +1,20 @@
+-- +goose Up
+
+-- Enable pg_trgm extension
+CREATE EXTENSION IF NOT EXISTS pg_trgm;
+
+-- Dropping incorrect index on the 'name' column
+DROP INDEX IF EXISTS "idx_name_gin:gin";
+
+-- Creating a new GIN index for full-text search on the 'name' column
+CREATE INDEX idx_name_gin ON public.reference_objects 
+USING gin(to_tsvector('english', name));
+
+-- Creating a new GIN index for trigram matching on the 'path' column
+CREATE INDEX idx_path_gin_trgm ON public.reference_objects USING gin(path gin_trgm_ops);
+
+-- +goose Down
+
+DROP INDEX IF EXISTS idx_path_gin_trgm;
+DROP INDEX IF EXISTS idx_name_gin;
+CREATE INDEX IF NOT EXISTS "idx_name_gin:gin" ON public.reference_objects USING btree (name);