我使用水晶32.1和凯末尔。如果我有运行时异常，打印回溯需要 21 秒。知道为什么需要这么长时间吗？
500 GET /chats/by_sale/1 21280.52ms
回溯：
web_1 | I, [2020-02-07 17:57:33 +00:00 #1] INFO -- : [1]
web_1 | Exception: Expected string for object name (JSON::Error)
web_1 | from /usr/share/crystal/src/json/builder.cr:308:16 in 'start_scalar'
web_1 | from /usr/share/crystal/src/json/builder.cr:295:11 in 'start_scalar'
web_1 | from /usr/share/crystal/src/json/builder.cr:194:5 in 'start_object'
web_1 | from src/service/json.cr:220:5 in 'object'
web_1 | from src/controller/chat.cr:37:5 in '->'
web_1 | from lib/kemal/src/kemal/route.cr:255:3 in '->'
web_1 | from lib/kemal/src/kemal/route_handler.cr:255:3 in 'process_request'
web_1 | from lib/kemal/src/kemal/route_handler.cr:17:7 in 'call'
web_1 | from /usr/share/crystal/src/http/server/handler.cr:26:7 in 'call_next'
web_1 | from lib/kemal/src/kemal/websocket_handler.cr:13:14 in 'call'
web_1 | from /usr/share/crystal/src/http/server/handler.cr:26:7 in 'call_next'
web_1 | from lib/kemal/src/kemal/filter_handler.cr:21:7 in 'call'
web_1 | from /usr/share/crystal/src/http/server/handler.cr:26:7 in 'call_next'
web_1 | from src/middleware/authenticate.cr:17:7 in 'call'
web_1 | from /usr/share/crystal/src/http/server/handler.cr:26:7 in 'call_next'
web_1 | from lib/kemal/src/kemal/static_file_handler.cr:68:9 in 'call'
web_1 | from /usr/share/crystal/src/http/server/handler.cr:26:7 in 'call_next'
web_1 | from lib/kemal/src/kemal/exception_handler.cr:8:7 in 'call'
web_1 | from /usr/share/crystal/src/http/server/handler.cr:26:7 in 'call_next'
web_1 | from lib/kemal/src/kemal/log_handler.cr:8:37 in 'call'
web_1 | from /usr/share/crystal/src/http/server/handler.cr:26:7 in 'call_next'
web_1 | from lib/kemal/src/kemal/init_handler.cr:12:7 in 'call'
web_1 | from /usr/share/crystal/src/http/server/request_processor.cr:48:11 in 'process'
web_1 | from /usr/share/crystal/src/http/server/request_processor.cr:22:3 in 'process'
web_1 | from /usr/share/crystal/src/http/server.cr:497:5 in 'handle_client'
web_1 | from /usr/share/crystal/src/http/server.cr:463:13 in '->'
web_1 | from /usr/share/crystal/src/fiber.cr:255:3 in 'run'
web_1 | from /usr/share/crystal/src/fiber.cr:47:34 in '->'
web_1 | from ???
web_1 |
web_1 | 2020-02-07 17:57:54 UTC 500 GET /chats/by_sale/1 21280.52ms
大的评论，所以把它作为一个答案。
我如何处理这个问题，方法是在 gdb 中运行您的服务器，然后在"21 秒暂停的中间"您在服务器中按 ctrl+c。 它会把你放到gdb。 然后运行 gdbbacktrace命令，看看它是否告诉您任何信息。 另一种选择可能是在其上运行分析器，这里提到了一些：甚至是gdb"穷人的剖析器"，它也适用于水晶(在OS X中，sample命令执行类似的FWIW(，并在有问题的减速期间运行它。