sessionctx, executor: Add correctness check when set system variables #7117

spongedu · 2018-07-20T15:45:57Z

What have you changed? (mandatory)

Add correctness check when set system variables

What is the type of the changes? (mandatory)

Improvement (non-breaking change which is an improvement to an existing feature)

How has this PR been tested? (mandatory)

Unittest

shenli · 2018-07-22T03:33:15Z

@spongedu Thanks! Is it the same behaviour with MySQL?

shenli · 2018-07-22T03:33:22Z

/run-all-tests

spongedu · 2018-07-22T04:11:08Z

@shenli Yes，this pr add the same type & value check as MySQL do.
Not all system variables are checked because there are too much of them, but after this PR we can fix the others concurrently.
Currently, if we give wrong value to TiDB specific system variable, a default value will be set and no warning or error is raised. I suggest that we deal with TiDB specific system variable the same way as MySQL system variable, that would be less confusing if the user use wrong value.

winkyao · 2018-07-23T03:14:47Z

Please fix ci.

XuHuaiyu

Great job~
Does all the mysql system vars has been tested in MySQL5.7?

XuHuaiyu · 2018-07-23T10:54:42Z

sessionctx/variable/varsutil.go

@@ -156,6 +165,181 @@ func ValidateGetSystemVar(name string, isGlobal bool) error {
 	return nil
 }

+// ValidateSetSystemVar checks if system variable satisfies specific restriction.
+func ValidateSetSystemVar(name string, value string) (string, error, error) {


We may not need to return warn?

yes, If we take the SessionVars as a parameter into function ValidateSetSystemVar, we can directly append warning in this function. I'll fix this

XuHuaiyu · 2018-07-23T11:01:21Z

sessionctx/variable/varsutil.go

+		if val := GetSysVar(name); val != nil {
+			return val.Value, nil, nil
+		}
+		return value, nil, nil


Any case cover this line?

In set_test.go, line 93 - line 97 covers this:

tk.MustQuery(`select @@global.low_priority_updates;`).Check(testkit.Rows("0")) tk.MustExec(`set @@global.low_priority_updates="ON";`) tk.MustQuery(`select @@global.low_priority_updates;`).Check(testkit.Rows("1")) tk.MustExec(`set @@global.low_priority_updates=DEFAULT;`) // It will be set to compiled-in default value. tk.MustQuery(`select @@global.low_priority_updates;`).Check(testkit.Rows("0"))

Yeah, this case covers line 172, but seems there is no case that covers line 174?

It seems so. I'll add some related tests..

@XuHuaiyu the condition that we fail to GetSysVar should never happen. We'd better panic here ?

spongedu · 2018-07-23T11:24:20Z

@XuHuaiyu Yes, these checks are according to https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#

XuHuaiyu · 2018-07-24T02:08:19Z

sessionctx/variable/varsutil.go

+			return val.Value, nil
+		}
+		// should never happen
+		panic(fmt.Sprintf("Error happened when ValidateSetSystemVar. Invalid system variable: %s", name))


Will it be more friendly if we return UnknownSystemVar.GenByArgs(name) here

XuHuaiyu

Addressing the comment will make a LGTM ^_^

zhexuany · 2018-07-24T07:44:15Z

sessionctx/variable/varsutil.go

@@ -156,6 +162,197 @@ func ValidateGetSystemVar(name string, isGlobal bool) error {
 	return nil
 }

+// ValidateSetSystemVar checks if system variable satisfies specific restriction.
+func ValidateSetSystemVar(vars *SessionVars, name string, value string) (string, error) {
+	if strings.EqualFold(value, "DEFAULT") {


Maybe we need to consider System? Currently, set time_zone='System' does not work.

@zhexuany it's not a common check, I think we'd better by refine parseTimeZone in varsutil.go to :

func parseTimeZone(s string) (*time.Location, error) { if strings.EqualFold(s, "SYSTEM") { ....... }

It seems that we should validate the result format in ValidateSetSystemVar. Only modify parseTimeZone is not enough. I'll fix here.

tidb> set time_zone='System'; Query OK, 0 rows affected (0.00 sec) tidb> select @@time_zone; +-------------+ | @@time_zone | +-------------+ | System | +-------------+ 1 row in set (0.00 sec)

In MySQL:

mysql> set time_zone='System'; Query OK, 0 rows affected (0.00 sec) mysql> select @@time_zone; +-------------+ | @@time_zone | +-------------+ | SYSTEM | +-------------+ 1 row in set (0.01 sec)

@zhexuany Done here. PTAL

shenli · 2018-07-24T10:07:45Z

@zhexuany @XuHuaiyu PTAL

XuHuaiyu

LGTM

zhexuany

LGTM

…pingcap#7117) (pingcap#8876)

…7117), (#8876) (#9413)

spongedu added 7 commits July 20, 2018 17:29

sessionctx, executor: Add correctness check when set system variables

fa16c09

Add tests

394a7ad

Code format refine

88a630a

fix spell

ba9834f

Take some more sysvars into check

6070034

Merge remote-tracking branch 'upstream/master' into dc_0720

87fc695

fix spell

fb7929b

shenli added the contribution This PR is from a community contributor. label Jul 22, 2018

Merge remote-tracking branch 'upstream/master' into dc_0720

128ffdb

spongedu added 2 commits July 22, 2018 21:57

Merge remote-tracking branch 'upstream/master' into dc_0720

1aed328

1. support set default 2. add more checks

fba76e3

spongedu added 4 commits July 23, 2018 11:23

Fix build

71ff2ac

Merge remote-tracking branch 'upstream/master' into dc_0720

65b88ae

Merge remote-tracking branch 'upstream/master' into dc_0720

bfd3b4a

Merge remote-tracking branch 'upstream/master' into dc_0720

ad2f279

XuHuaiyu reviewed Jul 23, 2018

View reviewed changes

XuHuaiyu added the type/compatibility label Jul 23, 2018

XuHuaiyu added this to the 2.1 milestone Jul 23, 2018

XuHuaiyu reviewed Jul 23, 2018

View reviewed changes

refine ValidateSetSystemVar

3273f75

XuHuaiyu reviewed Jul 24, 2018

View reviewed changes

spongedu added 2 commits July 24, 2018 11:12

return UnknownSystemVar error if sysvar not found

57961c6

Merge remote-tracking branch 'upstream/master' into dc_0720

fa4f79e

zhexuany reviewed Jul 24, 2018

View reviewed changes

spongedu added 2 commits July 24, 2018 16:15

Add check for time_zone

ab814bd

Merge branch 'master' into dc_0720

5ab0cb7

XuHuaiyu reviewed Jul 24, 2018

View reviewed changes

zhexuany approved these changes Jul 24, 2018

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XuHuaiyu approved these changes Jul 24, 2018

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XuHuaiyu merged commit 437933d into pingcap:master Jul 24, 2018

spongedu deleted the dc_0720 branch July 24, 2018 10:59

spongedu mentioned this pull request Jul 30, 2018

Complete correctness for system variables #7195

Closed

FateTHarlaown mentioned this pull request Sep 16, 2018

executor,sessionctx:Add correctness for system variable: sync_binlog,… #7716

Merged

This was referenced Nov 7, 2018

Add check for system variables validate_password_xxxx #8226

Closed

executor, sessionctx: add checks for system variable validate_password_xxxx #8227

Merged

crazycs520 added a commit to crazycs520/tidb that referenced this pull request Feb 21, 2019

sessionctx, executor: Add correctness check when set system variables (…

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…pingcap#7117) (pingcap#8876)

crazycs520 mentioned this pull request Feb 21, 2019

sessionctx/variable: Add correctness check when set system variables (#7117), (#8876) #9413

Merged

zz-jason pushed a commit that referenced this pull request Feb 22, 2019

sessionctx/variable: Add correctness check when set system variables (#…

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…7117), (#8876) (#9413)

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sessionctx, executor: Add correctness check when set system variables #7117

sessionctx, executor: Add correctness check when set system variables #7117

spongedu commented Jul 20, 2018

shenli commented Jul 22, 2018

shenli commented Jul 22, 2018

spongedu commented Jul 22, 2018

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sessionctx, executor: Add correctness check when set system variables #7117

sessionctx, executor: Add correctness check when set system variables #7117

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spongedu commented Jul 20, 2018

What have you changed? (mandatory)

What is the type of the changes? (mandatory)

How has this PR been tested? (mandatory)

shenli commented Jul 22, 2018

shenli commented Jul 22, 2018

spongedu commented Jul 22, 2018

winkyao commented Jul 23, 2018

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spongedu commented Jul 23, 2018

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shenli commented Jul 24, 2018

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