text: drop index idx1_tdx_stock_day;
  drop index idx2_tdx_stock_day;
  -- 创建索引的性能很差 （collate default）
  create index idx1_tdx_stock_day on tdx_stock_day (symbol);
  -- 创建索引的性能提高很多倍，因此英文字段表定义时使用collate "C"
  create index idx1_tdx_stock_day on tdx_stock_day (symbol collate "C");
  
  
  create index idx2_tdx_stock_day on tdx_stock_day (date);
  
  
  CREATE INDEX  "idx2_diffvalue_stock_stats_d" ON "public"."diffvalue_stock_stats_d" (lower(symbol));
  CREATE INDEX  "idx3_diffvalue_stock_stats_d" ON "public"."diffvalue_stock_stats_d" (date);
  
  -- TODO:symbol统一成小写
  CREATE INDEX  "idx3_xueqiu_stock_day_fq" ON "public"."xueqiu_stock_day_fq" (upper(symbol));
  