paincs: accessing the hot store

[liukun4515]

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

• pd cluster without tikv

2. What did you expect to see?

return null just like hot write and hot read

» hot read
null

» hot write
null

3. What did you see instead?

» hot store
Failed to get hotspot: [500] PANIC: runtime error: invalid memory address or nil pointer dereference
goroutine 15819 [running]:
github.com/pingcap/pd/vendor/github.com/urfave/negroni.(*Recovery).ServeHTTP.func1(0x8422a0cc38, 0x42297a420, 0x42299b130, 0x422ab2600)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/recovery.go:159 +0xef
panic(0x1becc00, 0x24d54e0)
        /usr/local/go/src/runtime/panic.go:502 +0x229
github.com/pingcap/pd/server.(*clusterInfo).getStoresBytesWriteStat(0x0, 0x0)
        /Users/liukun/go/src/github.com/pingcap/pd/server/cluster_info.go:220 +0x2f
github.com/pingcap/pd/server.(*Handler).GetHotBytesWriteStores(0x42298ef40, 0x1)
        /Users/liukun/go/src/github.com/pingcap/pd/server/handler.go:118 +0x39
github.com/pingcap/pd/server/api.(*hotStatusHandler).GetHotStores(0x422b58180, 0x8422a0cc38, 0x42297a428, 0x4229c2700)
        /Users/liukun/go/src/github.com/pingcap/pd/server/api/hot_status.go:51 +0x43
github.com/pingcap/pd/server/api.(*hotStatusHandler).GetHotStores-fm(0x8422a0cc38, 0x42297a428, 0x4229c2700)
        /Users/liukun/go/src/github.com/pingcap/pd/server/api/router.go:79 +0x48
net/http.HandlerFunc.ServeHTTP(0x422b58250, 0x8422a0cc38, 0x42297a428, 0x4229c2700)
        /usr/local/go/src/net/http/server.go:1947 +0x44
github.com/pingcap/pd/vendor/github.com/gorilla/mux.(*Router).ServeHTTP(0x42298db90, 0x8422a0cc38, 0x42297a428, 0x4229c2700)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/gorilla/mux/mux.go:159 +0xed
github.com/pingcap/pd/vendor/github.com/urfave/negroni.Wrap.func1(0x8422a0cc38, 0x42297a428, 0x4229c2500, 0x422b2e0e0)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:46 +0x4d
github.com/pingcap/pd/vendor/github.com/urfave/negroni.HandlerFunc.ServeHTTP(0x422b94900, 0x8422a0cc38, 0x42297a428, 0x4229c2500, 0x422b2e0e0)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:29 +0x4e
github.com/pingcap/pd/vendor/github.com/urfave/negroni.middleware.ServeHTTP(0x1e9a5e0, 0x422b94900, 0x422b94960, 0x8422a0cc38, 0x42297a428, 0x4229c2500)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:38 +0xa5
github.com/pingcap/pd/vendor/github.com/urfave/negroni.(middleware).ServeHTTP-fm(0x8422a0cc38, 0x42297a428, 0x4229c2500)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:38 +0x60
github.com/pingcap/pd/server/api.(*redirector).ServeHTTP(0x4229962d8, 0x8422a0cc38, 0x42297a428, 0x4229c2500, 0x422b2e060)
        /Users/liukun/go/src/github.com/pingcap/pd/server/api/redirector.go:45 +0x4f3
github.com/pingcap/pd/vendor/github.com/urfave/negroni.middleware.ServeHTTP(0x1e98220, 0x4229962d8, 0x422b94940, 0x8422a0cc38, 0x42297a428, 0x4229c2500)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:38 +0xa5
github.com/pingcap/pd/vendor/github.com/urfave/negroni.(*Negroni).ServeHTTP(0x422b75740, 0x8422a0cc38, 0x42297a420, 0x4229c2500)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:96 +0xf2
github.com/pingcap/pd/vendor/github.com/gorilla/mux.(*Router).ServeHTTP(0x42298d490, 0x8422a0cc38, 0x42297a420, 0x4229c2500)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/gorilla/mux/mux.go:159 +0xed
github.com/pingcap/pd/vendor/github.com/urfave/negroni.Wrap.func1(0x8422a0cc38, 0x42297a420, 0x422ab2600, 0x422b2e020)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:46 +0x4d
github.com/pingcap/pd/vendor/github.com/urfave/negroni.HandlerFunc.ServeHTTP(0x422b949a0, 0x8422a0cc38, 0x42297a420, 0x422ab2600, 0x422b2e020)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:29 +0x4e
github.com/pingcap/pd/vendor/github.com/urfave/negroni.middleware.ServeHTTP(0x1e9a5e0, 0x422b949a0, 0x422b94a00, 0x8422a0cc38, 0x42297a420, 0x422ab2600)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:38 +0xa5
github.com/pingcap/pd/vendor/github.com/urfave/negroni.(middleware).ServeHTTP-fm(0x8422a0cc38, 0x42297a420, 0x422ab2600)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:38 +0x60
github.com/pingcap/pd/vendor/github.com/urfave/negroni.(*Recovery).ServeHTTP(0x42299b130, 0x8422a0cc38, 0x42297a420, 0x422ab2600, 0x4229ebfc0)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/recovery.go:193 +0x8c
github.com/pingcap/pd/vendor/github.com/urfave/negroni.middleware.ServeHTTP(0x1e99000, 0x42299b130, 0x422b949e0, 0x8422a0cc38, 0x42297a420, 0x422ab2600)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:38 +0xa5
github.com/pingcap/pd/vendor/github.com/urfave/negroni.(*Negroni).ServeHTTP(0x422989800, 0x1ea72e0, 0x423028460, 0x422ab2600)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/urfave/negroni/negroni.go:96 +0xf2
net/http.(*ServeMux).ServeHTTP(0x422f5adb0, 0x1ea72e0, 0x423028460, 0x422ab2600)
        /usr/local/go/src/net/http/server.go:2337 +0x130
github.com/pingcap/pd/vendor/github.com/coreos/etcd/embed.(*accessController).ServeHTTP(0x422fd30a0, 0x1ea72e0, 0x423028460, 0x422ab2600)
        /Users/liukun/go/src/github.com/pingcap/pd/vendor/github.com/coreos/etcd/embed/serve.go:342 +0x14c
net/http.serverHandler.ServeHTTP(0x4229832b0, 0x1ea72e0, 0x423028460, 0x422ab2600)
        /usr/local/go/src/net/http/server.go:2694 +0xbc
net/http.(*conn).serve(0x422b3e960, 0x1ea8860, 0x422dba400)
        /usr/local/go/src/net/http/server.go:1830 +0x651
created by net/http.(*Server).Serve
        /usr/local/go/src/net/http/server.go:2795 +0x27b

4. What version of PD are you using (pd-server -V)?

[disksing]

PTAL @nolouch

[rleungx]

I'm going to fix it.