basalt-26.3.2-rc-20260908: sql/schemachange: TestColumnConversions failed

sql/schemachange.TestColumnConversions [failed](https://mesolite.cluster.engflow.com/invocations/default/4e6b3e4b-4f3a-4ae0-ac38-acabe7fa7d66?testReportRun=1&testReportShard=1&testReportAttempt=1#targets-Ly9wa2cvc3FsL3NjaGVtYWNoYW5nZTpzY2hlbWFjaGFuZ2VfdGVzdA==) on basalt-26.3.2-rc-20260908 @ [807558e5e81666af257c811e925e4cae570abc28](https://github.com/cockroachdb/cockroach/commits/807558e5e81666af257c811e925e4cae570abc28):

```
github.com/cockroachdb/cockroach/pkg/rpc.gatewayRequestRecoveryInterceptor({0xa3778d0, 0xc0016e8270}, {0x9e3db80, 0xc017fffce0}, 0xc033b066e0?, 0xc02cd02100)
pkg/rpc/metrics.go:803 +0x183
google.golang.org/grpc.getChainUnaryHandler.func1.getChainUnaryHandler.1({0xa3778d0, 0xc0016e8270}, {0x9e3db80, 0xc017fffce0})
external/org_golang_google_grpc/server.go:1177 +0x11f
github.com/cockroachdb/cockroach/pkg/server.newGRPCServer.NewRequestMetricsInterceptor.func4({0xa3778d0, 0xc0016e8270}, {0x9e3db80, 0xc017fffce0}, 0xc033b066e0, 0xc02cd020c0)
pkg/rpc/metrics.go:589 +0x3a2
google.golang.org/grpc.getChainUnaryHandler.func1({0xa3778d0, 0xc0016e8270}, {0x9e3db80, 0xc017fffce0})
external/org_golang_google_grpc/server.go:1177 +0x23d
github.com/cockroachdb/cockroach/pkg/rpc.NewServerEx.func1.1({0xa3778d0, 0xc0016e8270})
pkg/rpc/context.go:139 +0x6b
github.com/cockroachdb/cockroach/pkg/util/stop.(*Stopper).RunTaskWithErr(0xc0014bd040, {0xa3778d0, 0xc0016e8270}, {0x9f867c0, 0x21}, 0xc01821b6c8)
pkg/util/stop/stopper.go:358 +0x237
github.com/cockroachdb/cockroach/pkg/rpc.NewServerEx.func1({0xa3778d0, 0xc0016e8270}, {0x9e3db80, 0xc017fffce0}, 0xc033b066e0, 0xc02cd02080)
pkg/rpc/context.go:137 +0x14c
google.golang.org/grpc.NewServer.chainUnaryServerInterceptors.chainUnaryInterceptors.func1({0xa3778d0, 0xc0016e8270}, {0x9e3db80, 0xc017fffce0}, 0xc033b066e0, 0xc015e37770)
external/org_golang_google_grpc/server.go:1168 +0xe8
github.com/cockroachdb/cockroach/pkg/kv/kvpb._Internal_Batch_Handler({0x9e2f580, 0xc003962808}, {0xa3778d0, 0xc0016e8270}, 0xc014d5c4d0, 0xc00304fce0)
bazel-out/k8-fastbuild/bin/pkg/kv/kvpb/kvpb_go_proto_/github.com/cockroachdb/cockroach/pkg/kv/kvpb/api.pb.go:12526 +0x1e7
google.golang.org/grpc.(*Server).processUnaryRPC(0xc00181ba40, {0xa3d7d00, 0xc022ffb520}, 0xc0267f6000, 0xc001c8aab0, 0x106d2700, 0x0)
external/org_golang_google_grpc/server.go:1358 +0x1871
google.golang.org/grpc.(*Server).handleStream(0xc00181ba40, {0xa3d7d00, 0xc022ffb520}, 0xc0267f6000, 0x0)
external/org_golang_google_grpc/server.go:1735 +0xff3
google.golang.org/grpc.(*Server).serveStreams.func1.1()
external/org_golang_google_grpc/server.go:970 +0x173
created by google.golang.org/grpc.(*Server).serveStreams.func1 in goroutine 5711
external/org_golang_google_grpc/server.go:981 +0x253

goroutine 246142 [select]:
github.com/cockroachdb/cockroach/pkg/sql.(*ieResultChannel).firstResult(0xc022f0dbc0, {0xa378e08, 0xc0288bfae0})
pkg/sql/internal_result_channel.go:118 +0x186
github.com/cockroachdb/cockroach/pkg/sql.(*ieResultChannel).nextResult(0xc022f0dbc0, {0xa378e08, 0xc0288bfae0})
pkg/sql/internal_result_channel.go:157 +0x16d
github.com/cockroachdb/cockroach/pkg/sql.(*rowsIterator).Next(0xc025fab4d0, {0xa378e08, 0xc0288bfae0})
pkg/sql/internal.go:555 +0x1b6
github.com/cockroachdb/cockroach/pkg/sql.(*InternalExecutor).execIEStmt(_, {_, _}, {_, _}, _, {{{0x9ee430f, 0x4}}, {0x0, 0x0}, ...}, ...)
pkg/sql/internal.go:881 +0x3ea
github.com/cockroachdb/cockroach/pkg/sql.(*InternalExecutor).ExecEx(...)
pkg/sql/internal.go:829
github.com/cockroachdb/cockroach/pkg/sql.(*InternalExecutor).Exec(0xc013a20000, {0xa378e08, 0xc0288bfae0}, {0x9f007fa, 0xc}, 0x0, {0xc0124e6f50, 0x70}, {0x0, 0x0, ...})
pkg/sql/internal.go:813 +0x3f0
github.com/cockroachdb/cockroach/pkg/sql/stats.(*Refresher).refreshStats(0xc022067a00, {0xa378e08, 0xc0288bfae0}, 0x54, 0x6fc23ac00, 0x1)
pkg/sql/stats/automatic_stats.go:1323 +0x4d0
github.com/cockroachdb/cockroach/pkg/sql/stats.(*Refresher).maybeRefreshStats(0xc022067a00, {0xa378e08, 0xc0288bfae0}, 0x54, 0x0, 0x248, 0x6fc23ac00, 0x1, 0x1)
pkg/sql/stats/automatic_stats.go:1290 +0x345
github.com/cockroachdb/cockroach/pkg/sql/stats.(*Refresher).Start.func1.2({0xa378e08, 0xc0288bfae0})
pkg/sql/stats/automatic_stats.go:728 +0x866
github.com/cockroachdb/cockroach/pkg/util/stop.(*Stopper).RunAsyncTaskEx.func1({0xa378e08, 0xc0288bfae0})
pkg/util/stop/stopper.go:447 +0x113
created by github.com/cockroachdb/cockroach/pkg/util/stop.(*Stopper).RunAsyncTaskEx in goroutine 13781
pkg/util/stop/stopper.go:445 +0x247
```

Parameters:
- attempt=1
- race=true
- run=1
- shard=1
Help

See also: [How To Investigate a Go Test Failure \(internal\)](https://cockroachlabs.atlassian.net/l/c/HgfXfJgM)

Same failure on other branches

- #174878 basalt-26.3: sql/schemachange: TestColumnConversions failed [C-test-failure O-robot P-2 T-sql-foundations branch-basalt-26.3]

/cc @cockroachlabs/sql-foundations

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*TestColumnConversions.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Start with the sql/schemachange.TestColumnConversions failure report and reproduce it with race=true. Read the stack frames in pkg/sql/stats/automatic_stats.go, pkg/sql/internal.go, and pkg/rpc/metrics.go to identify the relevant failure path. Done means the test passes reliably on the affected branch and the regression is covered by the test.

Written by the indexing model from the issue text.