session: fix bootstrap error in ANSI sql_mode

[tiancaiamao]

What problem does this PR solve?

After setting sql_mode to ANSI, TiDB panic on startup:

set @@global.sql_mode="NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION,ANSI"

2018/11/19 16:58:31.015 printer.go:39: [info] Welcome to TiDB.
2018/11/19 16:58:31.015 printer.go:40: [info] Release Version: v2.1.0-rc.5
2018/11/19 16:58:31.015 printer.go:41: [info] Git Commit Hash: a6d2c0e11eb5618cd1d8a74bfc18df3067a59edb
2018/11/19 16:58:31.015 printer.go:42: [info] Git Branch: release-2.1
2018/11/19 16:58:31.015 printer.go:43: [info] UTC Build Time: 2018-11-12 11:55:18
2018/11/19 16:58:31.015 printer.go:44: [info] GoVersion: go version go1.11 linux/amd64
2018/11/19 16:58:31.015 printer.go:45: [info] Race Enabled: false
2018/11/19 16:58:31.015 printer.go:46: [info] Check Table Before Drop: false
2018/11/19 16:58:31.015 printer.go:47: [info] TiKV Min Version: 2.1.0-alpha.1-ff3dd160846b7d1aed9079c389fc188f7f5ea13e
2018/11/19 16:58:31.015 printer.go:52: [info] Config: {"host":"0.0.0.0","advertise-address":"192.168.0.202","port":4000,"store":"tikv","path":"192.168.0.201:2379,192.168.0.202:2379,192.168.
0.203:2379","socket":"","lease":"45s","run-ddl":true,"split-table":true,"token-limit":1000,"oom-action":"log","mem-quota-query":34359738368,"enable-streaming":false,"txn-local-latches":

{"en abled":false,"capacity":10240000}
,"lower-case-table-names":2,"log":{"level":"info","format":"text","disable-timestamp":false,"file":

{"filename":"/data0/deploy/log/tidb.log","log-rotate":tru e,"max-size":300,"max-days":0,"max-backups":0}
,"slow-query-file":"","slow-threshold":300,"expensive-threshold":10000,"query-log-max-len":2048},"security":

{"skip-grant-table":false,"ssl-ca": "","ssl-cert":"","ssl-key":"","cluster-ssl-ca":"","cluster-ssl-cert":"","cluster-ssl-key":""}
,"status":{"report-status":true,"status-port":10080,"metrics-addr":"","metrics-interval":15},"pe
rformance":

{"max-procs":0,"tcp-keep-alive":true,"cross-join":true,"stats-lease":"3s","run-auto-analyze":true,"stmt-count-limit":5000,"feedback-probability":0.05,"query-feedback-limit":1024, "pseudo-estimate-ratio":0.8,"force-priority":"NO_PRIORITY"}
,"xprotocol":{"xserver":false,"xhost":"","xport":0,"xsocket":""},"prepared-plan-cache":{"enabled":false,"capacity":100},"opentraci
ng":{"enable":false,"sampler":

{"type":"const","param":1,"sampling-server-url":"","max-operations":0,"sampling-refresh-interval":0}
,"reporter":

{"queue-size":0,"buffer-flush-interval":0,"log- spans":false,"local-agent-host-port":""}
,"rpc-metrics":false},"proxy-protocol":{"networks":"","header-timeout":5},"tikv-client":

{"grpc-connection-count":16,"grpc-keepalive-time":10,"grpc-ke epalive-timeout":3,"commit-timeout":"41s"}
,"binlog":{"enable":false,"write-timeout":"15s","ignore-error":false},"compatible-kill-query":false}
2018/11/19 16:58:31.015 main.go:196: [info] disable Prometheus push client
2018/11/19 16:58:31.015 tidb.go:260: [info] new store
2018/11/19 16:58:31.015 client.go:124: [info] [pd] create pd client with endpoints [192.168.0.201:2379 192.168.0.202:2379 192.168.0.203:2379]
2018/11/19 16:58:31.015 systime_mon.go:24: [info] start system time monitor
2018/11/19 16:58:31.017 client.go:226: [info] [pd] leader switches to: http://192.168.0.203:2379, previous:
2018/11/19 16:58:31.017 client.go:143: [info] [pd] init cluster id 6624403977823135243
2018/11/19 16:58:31.025 tidb.go:61: [info] store tikv-6624403977823135243 new domain, ddl lease 45s, stats lease 3000000000
2018/11/19 16:58:31.025 ddl.go:360: [info] [ddl] start DDL:5ab0971e-6043-41aa-b21c-21ae2263f749, run worker true
2018/11/19 16:58:31.026 ddl_worker.go:82: [info] [ddl] start delRangeManager OK, with emulator: false
2018/11/19 16:58:31.026 ddl_worker.go:82: [info] [ddl] start delRangeManager OK, with emulator: false
2018/11/19 16:58:31.026 ddl_worker.go:117: [info] [ddl-worker 1, tp general] start DDL worker
2018/11/19 16:58:31.026 ddl_worker.go:117: [info] [ddl-worker 2, tp add index] start DDL worker
2018/11/19 16:58:31.098 domain.go:125: [info] [ddl] full load InfoSchema from version 0 to 215, in 65.722955ms
2018/11/19 16:58:31.099 domain.go:322: [info] [ddl] full load and reset schema validator.
2018/11/19 16:58:31.103 session.go:809: [warning] con:0 compile error:
[planner:1054]Unknown column 'system_tz' in 'where clause'
select variable_value from mysql.tidb where variable_name = "system_tz"
2018/11/19 16:58:31.103 terror.go:327: [fatal] [planner:1054]Unknown column 'system_tz' in 'where clause'
github.com/pingcap/tidb/vendor/github.com/pkg/errors.AddStack
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/vendor/github.com/pkg/errors/errors.go:174
github.com/pingcap/tidb/terror.(*Error).GenWithStackByArgs
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/terror/terror.go:231
github.com/pingcap/tidb/planner/core.(*expressionRewriter).toColumn
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:1261
github.com/pingcap/tidb/planner/core.(*expressionRewriter).Leave
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:772
github.com/pingcap/tidb/ast.(*ColumnName).Accept
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/ast/expressions.go:412
github.com/pingcap/tidb/ast.(*ColumnNameExpr).Accept
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/ast/expressions.go:466
github.com/pingcap/tidb/ast.(*BinaryOperationExpr).Accept
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/ast/expressions.go:221
github.com/pingcap/tidb/planner/core.(*planBuilder).rewriteExprNode
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:133
github.com/pingcap/tidb/planner/core.(*planBuilder).rewriteWithPreprocess
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:105
github.com/pingcap/tidb/planner/core.(*planBuilder).rewrite
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/expression_rewriter.go:81
github.com/pingcap/tidb/planner/core.(*planBuilder).buildSelection
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/logical_plan_builder.go:463
github.com/pingcap/tidb/planner/core.(*planBuilder).buildSelect
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/logical_plan_builder.go:1668
github.com/pingcap/tidb/planner/core.(*planBuilder).build
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/planbuilder.go:157
github.com/pingcap/tidb/planner/core.Optimize
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/planner/core/optimizer.go:74
github.com/pingcap/tidb/executor.(*Compiler).Compile
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/executor/compiler.go:48
github.com/pingcap/tidb/session.(*session).execute
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/session/session.go:806
github.com/pingcap/tidb/session.(*session).Execute
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/session/session.go:768
github.com/pingcap/tidb/session.loadSystemTZ
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/session/session.go:1090
github.com/pingcap/tidb/session.BootstrapSession
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/session/session.go:1115
main.createStoreAndDomain
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/tidb-server/main.go:166
main.main
/home/jenkins/workspace/build_tidb_2.1/go/src/github.com/pingcap/tidb/tidb-server/main.go:140
runtime.main
/usr/local/go/src/runtime/proc.go:201
runtime.goexit
/usr/local/go/src/runtime/asm_amd64.s:1333

What is changed and how it works?

Change
select variable_value from mysql.tidb where variable_name = "system_tz"
to
select variable_value from mysql.tidb where variable_name = 'system_tz'

Check List

Tests

• Unit test

Related changes

• Need to cherry-pick to the release branch

---

This change is 

[winoros]

lgtm
Description is wrong. Also, it's not a panic. It just returned error.

DNM

[tiancaiamao]

/run-all-tests

PTAL @winoros @zz-jason

[tiancaiamao]

/run-integration-ddl-test

[tiancaiamao]

PTAL @winkyao @winoros

[shenli]

LGTM
But the description is still wrong:

After setting sql_mode to ANSI, TiDB panic on startup:

[jackysp]

LGTM