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Servo typum descriptionis huius status sessionis in MySQL

2024-07-12

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MySQL servo instrumenti aliquot sessionum civitatis elit. Clientes hos investigatores efficere possunt ut mutationes status sessionis notificationes recipiant.

I propositum Sessio rei publicae Tracker

Sessionis status elit inserviunt sequentibus propositis:

  • ad sessionem faciliorem migrationem.
  • Facilitatem transactionis commutatione.

Venator mechanismum praebet viam ad MySQL connexiones et clientes applicationes ad determinandum num contextus sessionis quaevis praesto sit ut sessionem migrationem ab uno servo ad alium permittat. (Ad sessiones permutandas in ambitu onere librato, deprehendere necesse est num status sessionis sit quae ratio habenda est cum diiudicando num virga fieri potest).

Mechanismus venato concedit applicationes ad cognoscendum cum res ab una sessione ad aliam moveri possunt. Transactio status sequi hoc dat, quod est utile applicationibus qui negotia movere volunt a servo negotioso ad servo minus onerato. Exempli gratia, onere connexionis conpensationis quod lacus clientium nexus administrat transactiones inter sessiones in piscina praesto movere possunt.

Sed sessio commutatione aliquo tempore fieri non potest. Si sessio est in media transactione quae legere vel scribere confecerit, mutans in diversa sessione significat transactionem in pristino sessione revolvi. Sessionis commutatio solum fieri potest cum nullae operationes legere vel scribere intra gestum gestae sunt.

Exempla rerum quae rationabiliter transibunt:

Praeter statum transactionis intelligendi, etiam notas transactionis intelligere potes ut eisdem notis uti possis, cum res ad aliam sessionem movetur. Characteres sequentes cum hoc coniunguntur:

  1. READ ONLY
  2. READ WRITE
  3. ISOLATION LEVEL
  4. WITH CONSISTENT SNAPSHOT

II Available sessionis publica elit

Ad actiones investigationis sessionis sustinendas, notificationes ad sequentes rationes status sessionis clientium informationes praeberi possunt:

(1) Mutationes hae possessiones status sessionis clientis sunt;

  • Default schema (database).
  • Sessiones valores speciales pro variabilibus systematis.
  • User variables definitae.
  • Forma temporalis.
  • Parata oratio.

Session_track_state_change ratio variabilis hunc venatum moderatur.

(2) Mutato schematis defaltam nomine. Session_track_schema systematis variabilis hunc venatum moderatur.

(3) Muta valorem sessionis systematis variabilis. Session_track_system_variables systema variabilis hunc venatum moderatur. Permissio SENSITIVE_VARIABLES_OBSERVER requiritur ut mutationes in valoribus systematis sensitivarum variabilium indagant.

(4) Available GTID. Session_track_gtids ratio variabilis hunc venatum moderatur.

(5) Information about transactiones status et naturas. Session_track_transaction_info systematis variabilis hunc venatum moderatur.

Hae variabiles systematis imperium permittunt quarum mutationum notificationes fiunt, sed aditum notificationis informationis non praebent. Notification in MySQL client/servi/protocollo occurrit, quod includit venato informationes in OK facis ut deprehendas mutationes in statu sessionis.

3 C API sessionis status venato auxilio

Ut clientium applicationes ad extrahendam statum mutationis informationes ex OK facis redditum a servo, MySQL C API par munera praebet;

  • mysql_session_track_get_first() accipit primam partem status mutationis nuntiorum acceptorum a servo.
  • mysql_session_track_get_next() aliqua residua status mutationis notitiae a servo receptae accipit. Post felicem vocationem ad mysql_session_track_get_first(), hoc munus saepe vocatur dum successus redditur.

IV test suite sessionem publica venato firmamentum

Progressio mysqltest habet disable_session_track_info et enable_sessionutrack_ininfo mandata ad regendum sive inquisitor notificationes sessionis fiunt. His iussionibus uti potes ut notificationes per SQL constitutiones ex linea mandato prolatas videas. Finge testscript documentum continet mysqltest hoc scriptum:

  1. DROP TABLE IF EXISTS test.t1;
  2. CREATE TABLE test.t1 (i INT, f FLOAT);
  3. --enable_session_track_info
  4. SET @@SESSION.session_track_schema=ON;
  5. SET @@SESSION.session_track_system_variables='*';
  6. SET @@SESSION.session_track_state_change=ON;
  7. USE information_schema;
  8. SET NAMES 'utf8mb4';
  9. SET @@SESSION.session_track_transaction_info='CHARACTERISTICS';
  10. SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
  11. SET TRANSACTION READ WRITE;
  12. START TRANSACTION;
  13. SELECT 1;
  14. INSERT INTO test.t1 () VALUES();
  15. INSERT INTO test.t1 () VALUES(1, RAND());
  16. COMMIT;

Curre scriptor ut sequitur ad informationes provisum a elit enabled per videre. .

  1. $> mysqltest < testscript
  2. DROP TABLE IF EXISTS test.t1;
  3. CREATE TABLE test.t1 (i INT, f FLOAT);
  4. SET @@SESSION.session_track_schema=ON;
  5. SET @@SESSION.session_track_system_variables='*';
  6. -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
  7. -- session_track_system_variables
  8. -- *
  9. SET @@SESSION.session_track_state_change=ON;
  10. -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
  11. -- session_track_state_change
  12. -- ON
  13. USE information_schema;
  14. -- Tracker : SESSION_TRACK_SCHEMA
  15. -- information_schema
  16. -- Tracker : SESSION_TRACK_STATE_CHANGE
  17. -- 1
  18. SET NAMES 'utf8mb4';
  19. -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
  20. -- character_set_client
  21. -- utf8mb4
  22. -- character_set_connection
  23. -- utf8mb4
  24. -- character_set_results
  25. -- utf8mb4
  26. -- Tracker : SESSION_TRACK_STATE_CHANGE
  27. -- 1
  28. SET @@SESSION.session_track_transaction_info='CHARACTERISTICS';
  29. -- Tracker : SESSION_TRACK_SYSTEM_VARIABLES
  30. -- session_track_transaction_info
  31. -- CHARACTERISTICS
  32. -- Tracker : SESSION_TRACK_STATE_CHANGE
  33. -- 1
  34. -- Tracker : SESSION_TRACK_TRANSACTION_CHARACTERISTICS
  35. --
  36. -- Tracker : SESSION_TRACK_TRANSACTION_STATE
  37. -- ________
  38. SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
  39. -- Tracker : SESSION_TRACK_TRANSACTION_CHARACTERISTICS
  40. -- SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
  41. SET TRANSACTION READ WRITE;
  42. -- Tracker : SESSION_TRACK_TRANSACTION_CHARACTERISTICS
  43. -- SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; SET TRANSACTION READ WRITE;
  44. START TRANSACTION;
  45. -- Tracker : SESSION_TRACK_TRANSACTION_CHARACTERISTICS
  46. -- SET TRANSACTION ISOLATION LEVEL SERIALIZABLE; START TRANSACTION READ WRITE;
  47. -- Tracker : SESSION_TRACK_TRANSACTION_STATE
  48. -- T_______
  49. SELECT 1;
  50. 1
  51. 1
  52. -- Tracker : SESSION_TRACK_TRANSACTION_STATE
  53. -- T_____S_
  54. INSERT INTO test.t1 () VALUES();
  55. -- Tracker : SESSION_TRACK_TRANSACTION_STATE
  56. -- T___W_S_
  57. INSERT INTO test.t1 () VALUES(1, RAND());
  58. -- Tracker : SESSION_TRACK_TRANSACTION_STATE
  59. -- T___WsS_
  60. COMMIT;
  61. -- Tracker : SESSION_TRACK_TRANSACTION_CHARACTERISTICS
  62. --
  63. -- Tracker : SESSION_TRACK_TRANSACTION_STATE
  64. -- ________
  65. ok

Ante constitutionis initium transactionis, duas constitutiones NEGATIO SET faciendas, ut plani solitudinem constituant et modum notae accessus ad proximum transactionem ponant. Valor SESSION_TRACK_TRANSACTION_CHARACTERISTICS indicat valorem proximum transactionis appositum.

Post COMMERCIUM constitutionis finit negotium, valor inanis nuntiatur SESSION_TRACK_transaction_CHARACTERISTICS. Hoc significat proprietates proximae transactionis quae ante transactionem inchoatae sunt positae reset et defaltae sessionis applicandae sunt. Ad mutationes indagare his defaltis sessionis, indagare valorem sessionis de transaction_inisolation et transaction_read_sonum variabilium systematis.

Ut informationes de GTID inspicias, SESSION_TRACK_GTID investigatorem da utens SESSION_TRACK_GTID systematis variabilis.