[System Test] Panic in indexer - Error observed when processing Statistics

2024-02-22T06:35:48.546-08:00 [Info] Shard /data/@2i/shards/shard10523355994537715022(10523355994537715022)(6012689926613359440-0-0) : Shard.closeInstance: instance /data/@2i/bucket3_idx3_pOzo_10073953503448448880_5.index/mainIndex closed

2024-02-22T06:35:48.547-08:00 [Info] bucket3/idx3_pOzo/Mainstore#10073953503448448880:5 Plasma: Plasma.Close: Done closing plasma instance

2024-02-22T06:35:48.547-08:00 [Info] bucket3/idx3_pOzo/Backstore#10073953503448448880:5 Plasma: Plasma.Close: Begin closing plasma instance

2024-02-22T06:35:48.548-08:00 [Fatal] PlasmaSlice::Statistics Error observed when processing Statistics on instId: 11118697127090909452, partnId: 0

2024-02-22T06:35:48.548-08:00 [Info] bucket3/idx3_pOzo/Backstore#10073953503448448880:5 Plasma: Plasma.monitor: Received stop message

panic: runtime error: invalid memory address or nil pointer dereference [recovered]

	panic: runtime error: invalid memory address or nil pointer dereference

[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x11e4133]

goroutine 8269396 [running]:

github.com/couchbase/indexing/secondary/indexer.(*plasmaSlice).Statistics.func1()

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/plasma_slice.go:2883 +0xd4

panic({0x17ccc00?, 0x2e35180?})

	/home/couchbase/.cbdepscache/exploded/x86_64/go-1.21.6/go/src/runtime/panic.go:914 +0x21f

github.com/couchbase/nitro/skiplist.(*Skiplist).GetStats(...)

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/nitro/skiplist/stats.go:139

github.com/couchbase/plasma.(*Plasma).GetNumPages(...)

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/plasma/plasma.go:1158

github.com/couchbase/plasma.(*Plasma).getStats(_, _)

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/plasma/plasma.go:1171 +0xf3

github.com/couchbase/plasma.(*Plasma).GetPreparedStats(...)

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/plasma/plasma.go:1153

github.com/couchbase/indexing/secondary/indexer.(*plasmaSlice).Statistics(0xc00abc4600, 0x0)

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/plasma_slice.go:2898 +0x11c

github.com/couchbase/indexing/secondary/indexer.(*storageMgr).getIndexStorageStats(0xc0059a8340, 0x0)

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/storage_manager.go:1843 +0xb9e

github.com/couchbase/indexing/secondary/indexer.(*storageMgr).handleStats.func1()

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/storage_manager.go:1596 +0x105

created by github.com/couchbase/indexing/secondary/indexer.(*storageMgr).handleStats in goroutine 329

	/home/couchbase/jenkins/workspace/couchbase-server-unix/goproj/src/github.com/couchbase/indexing/secondary/indexer/storage_manager.go:1590 +0xb6