New interesting underscores for more than 255 _FIX_CONTROLs

I keep saying this – we have the best and most skilled customers. Christian Klose from my Franconian home region contacted me via LinkedIn and asked for some assistance with an SR. I confess, I replied way too late (information overflow). But the finding Christian had is great to know. There are new interesting underscores for more than 255 _FIX_CONTROLs.

Photo by Casey Horner on Unsplash

Why don’t you see them in ORAdiff?

As usual, I went to ORAdiff and tried to find out anything about these new _fix_control parameters. But I couldn’t find any indication for what Christian found. And then I read the bug:

• Bug 33501425 – ENABLING SUPPORT FOR MORE THAT 255 FIX_CONTROLS TO BE SET USING ALTER-SYSTEM

which honestly is not a bug but more an enhancement.

As the bug’s subject indicates we can store “only” 255 values in _fix_control. This is something you can easily test by enabling the disabled optimizer fixes in 19.26 or 19.27 with:

• execute dbms_optim_bundle.enable_optim_fixes('ON','BOTH', 'YES')

When you execute this, you will find a lengthy _fix_control parameter spanning many lines in your SPFILE. But we can only store 255 values in it. As soon as there are more values to store – and this can happen most likely given the lifetime of Oracle Database 19c into the 2030s, we will run into the limitation.

The databases creates those automatically

Now, in such a case, the database will automatically create additional _fix_control parameters but only if this is needed – which is happening only when the first parameter is fully occupied. In this case, you would see _fix_control_1 appearing in your SPFILE. With this transaction we added enough potential parameters for future settings and additions.

This is the list of _fix_controls in 19.26 since Release Updates are cumulative. You can check the same in ORAdiff.

SQL>  execute dbms_optim_bundle.getBugsforBundle(250121);

19.4.0.0.190719DBRU:

    Bug: 29331066,  fix_controls: 29331066

19.5.0.0.191015DBRU:

    Bug: 28965084,  fix_controls: 28965084

    Bug: 28776811,  fix_controls: 28776811

    Bug: 28498976,  fix_controls: 28498976

    Bug: 28567417,  fix_controls: 28567417

    Bug: 28558645,  fix_controls: 28558645

    Bug: 29132869,  fix_controls: 29132869

    Bug: 29450812,  fix_controls: 29450812

19.6.0.0.200114DBRU:

   No fixes with fix_controls applied as part of this bundle

19.7.0.0.200414DBRU:

    Bug: 29687220,  fix_controls: 29687220

    Bug: 29939400,  fix_controls: 29939400

    Bug: 30232638,  fix_controls: 30232638

    Bug: 30001331,  fix_controls: 30001331

19.8.0.0.200714DBRU:

    Bug: 29304314,  fix_controls: 29304314

    Bug: 29930457,  fix_controls: 29930457

    Bug: 30519188,  fix_controls: 30028663

    Bug: 28144569,  fix_controls: 28144569

    Bug: 28776431,  fix_controls: 28776431

19.9.0.0.201020DBRU:

    Bug: 27261477,  fix_controls: 27261477, 31069997, 31077481

    Bug: 28602253,  fix_controls: 28602253

    Bug: 31486557,  fix_controls: 29653132

    Bug: 29937655,  fix_controls: 29937655

    Bug: 30347410,  fix_controls: 30347410

    Bug: 30602828,  fix_controls: 30602828

    Bug: 30896685,  fix_controls: 30896685

19.10.0.0.210119DBRU:

    Bug: 29487407,  fix_controls: 29487407

    Bug: 30998035,  fix_controls: 30998035

    Bug: 30786641,  fix_controls: 30786641

    Bug: 31444353,  fix_controls: 31444353

    Bug: 30486896,  fix_controls: 30486896

    Bug: 28999046,  fix_controls: 28999046

    Bug: 30902655,  fix_controls: 30902655

    Bug: 30681521,  fix_controls: 30681521

    Bug: 29302565,  fix_controls: 29302565

    Bug: 30972817,  fix_controls: 30972817

    Bug: 30222669,  fix_controls: 30222669

    Bug: 31668694,  fix_controls: 31668694

    Bug: 31001490,  fix_controls: 31001490

    Bug: 30198239,  fix_controls: 30198239

    Bug: 30980115,  fix_controls: 30980115

    Bug: 30616738,  fix_controls: 30616738

    Bug: 31895670,  fix_controls: 31895670

    Bug: 19138896,  fix_controls: 19138896

    Bug: 31376708,  fix_controls: 31670824

    Bug: 30564898,  fix_controls: 9876287, 30564898

    Bug: 32234161,  fix_controls: 32075777

    Bug: 30842277,  fix_controls: 30570982

19.11.0.0.210420DBRU:

    Bug: 30927440,  fix_controls: 30927440

    Bug: 31788104,  fix_controls: 30822446

    Bug: 24561942,  fix_controls: 24561942

    Bug: 31625959,  fix_controls: 31625959

    Bug: 31976303,  fix_controls: 31579233

    Bug: 29696242,  fix_controls: 29696242

    Bug: 30228422,  fix_controls: 30228422

    Bug: 32122574,  fix_controls: 17295505

    Bug: 29725425,  fix_controls: 29725425

    Bug: 30618230,  fix_controls: 30618230

    Bug: 30008456,  fix_controls: 30008456

    Bug: 30537403,  fix_controls: 30537403

    Bug: 30235878,  fix_controls: 30235878

    Bug: 30646077,  fix_controls: 30646077

    Bug: 29657973,  fix_controls: 29657973

    Bug: 30527198,  fix_controls: 29712727

    Bug: 20922160,  fix_controls: 20922160

    Bug: 30006705,  fix_controls: 30006705

    Bug: 29463553,  fix_controls: 29463553

    Bug: 30751171,  fix_controls: 30751171

    Bug: 31009032,  fix_controls: 31009032

    Bug: 30207519,  fix_controls: 30063629, 30207519

    Bug: 31517502,  fix_controls: 31517502

    Bug: 30617002,  fix_controls: 30617002

    Bug: 30483217,  fix_controls: 30483217

    Bug: 30235691,  fix_controls: 30235691

    Bug: 30568514,  fix_controls: 30568514

    Bug: 28414968,  fix_controls: 28414968

    Bug: 32014520,  fix_controls: 32014520

    Bug: 30249927,  fix_controls: 30249927

    Bug: 31580374,  fix_controls: 31580374

    Bug: 29590666,  fix_controls: 29590666

    Bug: 29435966,  fix_controls: 29435966

    Bug: 29867728,  fix_controls: 28173995, 29867728

    Bug: 30776676,  fix_controls: 30776676

    Bug: 26577716,  fix_controls: 26577716

    Bug: 30470947,  fix_controls: 30470947

    Bug: 30979701,  fix_controls: 30979701

    Bug: 31435308,  fix_controls: 30483184, 31001295

    Bug: 31191224,  fix_controls: 31191224

    Bug: 31974424,  fix_controls: 31974424

    Bug: 29385774,  fix_controls: 29385774

    Bug: 28234255,  fix_controls: 28234255

19.12.0.0.210720DBRU:

    Bug: 31459242,  fix_controls: 31459242

    Bug: 31082719,  fix_controls: 31082719

    Bug: 28708585,  fix_controls: 28708585

    Bug: 31821701,  fix_controls: 31821701

    Bug: 32107621,  fix_controls: 32107621

    Bug: 26758837,  fix_controls: 26758837

    Bug: 31558194,  fix_controls: 31558194

    Bug: 30781970,  fix_controls: 30781970

    Bug: 30142527,  fix_controls: 30142527

    Bug: 31143146,  fix_controls: 31143146

    Bug: 31961578,  fix_controls: 31961578

    Bug: 31496840,  fix_controls: 31496840

    Bug: 22387320,  fix_controls: 22387320

    Bug: 30652595,  fix_controls: 30652595

19.13.0.0.211019DBRU:

    Bug: 25979242,  fix_controls: 25979242

    Bug: 32578113,  fix_controls: 32578113

    Bug: 32205825,  fix_controls: 32205825

    Bug: 32408640,  fix_controls: 32408640

    Bug: 31988833,  fix_controls: 31988833

    Bug: 32800137,  fix_controls: 32800137

    Bug: 31360214,  fix_controls: 31360214

    Bug: 32913527,  fix_controls: 32913527

    Bug: 32312412,  fix_controls: 29738374

    Bug: 33325981,  fix_controls: 33325981

19.14.0.0.220118DBRU:

    Bug: 31945701,  fix_controls: 31945701

    Bug: 32212062,  fix_controls: 32212062

    Bug: 32766397,  fix_controls: 32766397

    Bug: 32508585,  fix_controls: 32508585

    Bug: 29651517,  fix_controls: 29651517

    Bug: 31912834,  fix_controls: 31912834

    Bug: 33145153,  fix_controls: 33145153

    Bug: 33613512,  fix_controls: 31880080

19.15.0.0.220419DBRU:

    Bug: 31050103,  fix_controls: 31050103

    Bug: 30018126,  fix_controls: 30018126

    Bug: 33303725,  fix_controls: 33303725

    Bug: 32856375,  fix_controls: 32856375

    Bug: 32754044,  fix_controls: 32754044

    Bug: 33297275,  fix_controls: 33297275

    Bug: 32851615,  fix_controls: 32851615

    Bug: 32302470,  fix_controls: 32302470

    Bug: 27825962,  fix_controls: 27825962

    Bug: 33323903,  fix_controls: 33323903

    Bug: 31162457,  fix_controls: 31162457

    Bug: 31843716,  fix_controls: 31843716

19.16.0.0.220719DBRU:

    Bug: 28044739,  fix_controls: 28044739

    Bug: 30771009,  fix_controls: 30771009

    Bug: 33636280,  fix_controls: 33636280

    Bug: 33089096,  fix_controls: 31545400

    Bug: 30618406,  fix_controls: 30618406

    Bug: 32614157,  fix_controls: 32614157

    Bug: 33329027,  fix_controls: 33329027

    Bug: 33311488,  fix_controls: 33311488

    Bug: 32396085,  fix_controls: 32396085

    Bug: 32122197,  fix_controls: 29972495

    Bug: 32363981,  fix_controls: 32363981

19.17.0.0.221018DBRU:

    Bug: 31582179,  fix_controls: 31582179

    Bug: 30978868,  fix_controls: 30978868

    Bug: 33381775,  fix_controls: 33381775

    Bug: 33906515,  fix_controls: 33906515

    Bug: 33443834,  fix_controls: 33443834

    Bug: 33730024,  fix_controls: 33730024

    Bug: 33649782,  fix_controls: 33649782

    Bug: 33236729,  fix_controls: 33236729

    Bug: 34092979,  fix_controls: 34092979

    Bug: 33987911,  fix_controls: 33987911

    Bug: 34028486,  fix_controls: 34028486

    Bug: 32874571,  fix_controls: 32874571

    Bug: 31304975,  fix_controls: 26491973

    Bug: 30675651,  fix_controls: 30675651

    Bug: 10123661,  fix_controls: 10123661

    Bug: 30887435,  fix_controls: 30887435

    Bug: 33547527,  fix_controls: 30231086, 30195773, 31091402, 33547527

    Bug: 30222187,  fix_controls: 18101156

    Bug: 34428819,  fix_controls: 34428819

19.18.0.0.230117DBRU:

    Bug: 31209735,  fix_controls: 31209735

    Bug: 30609737,  fix_controls: 30609737

    Bug: 32498602,  fix_controls: 32498602

    Bug: 29499077,  fix_controls: 29499077

    Bug: 32378953,  fix_controls: 32527739

    Bug: 31821701,  fix_controls: 31266779, 31487332

    Bug: 25869323,  fix_controls: 25869323

    Bug: 31925765,  fix_controls: 31925765

    Bug: 33667505,  fix_controls: 33667505

    Bug: 32107664,  fix_controls: 33369863

    Bug: 32933936,  fix_controls: 32933936

    Bug: 34131435,  fix_controls: 34131435

    Bug: 34012165,  fix_controls: 33745469

    Bug: 34774426,  fix_controls: 29015273

    Bug: 34701323,  fix_controls: 34701323

    Bug: 34123350,  fix_controls: 34123350

    Bug: 34958012,  fix_controls: 32016340

19.19.0.0.230418DBRU:

    Bug: 34027770,  fix_controls: 34244753

    Bug: 34467295,  fix_controls: 34467295

    Bug: 23220873,  fix_controls: 23220873

    Bug: 32550281,  fix_controls: 32061341

    Bug: 33548186,  fix_controls: 33548186

    Bug: 33421972,  fix_controls: 33421972

    Bug: 34605306,  fix_controls: 32616683

19.20.0.0.230718DBRU:

    Bug: 33627879,  fix_controls: 33627879

    Bug: 32005394,  fix_controls: 32005394

    Bug: 33069936,  fix_controls: 33069936

    Bug: 35012562,  fix_controls: 35012562

    Bug: 34685578,  fix_controls: 34685578

    Bug: 34862366,  fix_controls: 31184370

    Bug: 35313797,  fix_controls: 35313797

    Bug: 35412607,  fix_controls: 35412607

19.21.0.0.231017DBRU:

    Bug: 34044661,  fix_controls: 34044661

    Bug: 34544657,  fix_controls: 33549743

    Bug: 34816383,  fix_controls: 34816383

    Bug: 35330506,  fix_controls: 35330506

19.22.0.0.240116DBRU:

    Bug: 34803323,  fix_controls: 34803323

    Bug: 31195441,  fix_controls: 31195441

    Bug: 34384239,  fix_controls: 34384239

    Bug: 34610498,  fix_controls: 34610498

    Bug: 35001214,  fix_controls: 34225667

    Bug: 35342306,  fix_controls: 32078078

    Bug: 30587089,  fix_controls: 30587089

    Bug: 35490676,  fix_controls: 32230780

19.23.0.0.240416DBRU:

    Bug: 35614342,  fix_controls: 35614342

    Bug: 24408754,  fix_controls: 24408754

    Bug: 31072746,  fix_controls: 31072746

    Bug: 35465301,  fix_controls: 35465301

    Bug: 35758002,  fix_controls: 35758002

    Bug: 28469386,  fix_controls: 28469386

    Bug: 34902561,  fix_controls: 34902561

    Bug: 36135987,  fix_controls: 35998456

19.24.0.0.240716DBRU:

    Bug: 35192015,  fix_controls: 35192015

    Bug: 35233495,  fix_controls: 35233495

    Bug: 35182694,  fix_controls: 35209735

19.25.0.0.241015DBRU:

    Bug: 34424818,  fix_controls: 34424818

    Bug: 36373767,  fix_controls: 32436948

    Bug: 35792419,  fix_controls: 34764262

    Bug: 36527753,  fix_controls: 36527753

    Bug: 33753810,  fix_controls: 33753810

    Bug: 31953809,  fix_controls: 31953809

    Bug: 36605166,  fix_controls: 36605166

    Bug: 36152460,  fix_controls: 35586002

19.26.0.0.250121DBRU:

    Bug: 35330725,  fix_controls: 35330725

    Bug: 36906464,  fix_controls: 36906464

    Bug: 36004220,  fix_controls: 31720959, 36004220

    Bug: 35665537,  fix_controls: 35365062, 35421474

    Bug: 31428395,  fix_controls: 31428395

    Bug: 36868551,  fix_controls: 35111847, 36868551

    Bug: 36698344,  fix_controls: 36698344

    Bug: 36717628,  fix_controls: 32321289

    Bug: 36373163,  fix_controls: 36373163

    Bug: 36994814,  fix_controls: 36994814

    Bug: 36549584,  fix_controls: 36549584

    Bug: 30758835,  fix_controls: 30758835

    Bug: 36040099,  fix_controls: 36040099

    Bug: 37456160,  fix_controls: 37065327

And guess how many these are?

That’s 240 _fix_controls all together. Maybe with 19.27 we’ll cross the 255 already.

The fix is already in the code since a longer while, but you won’t see it before you cross the boundary. This is why Christian found it now. But it is actually not a change in 19.26.0.

Further Links and Information

• DBMS_OPTIM_BUNDLE and disabling another fix
• Internal Only MOS Note: 3077904.1
• Bug 33501425 – ENABLING SUPPORT FOR MORE THAT 255 FIX_CONTROLS TO BE SET USING ALTER-SYSTEM

–Mike