[Vocabulary] A Critique of ANSI SQL Isolation Levels
Reference
https://www.microsoft.com/en-us/research/wp-content/uploads/2016/02/tr-95-51.pdf
1. Introduction
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| critique |
/krɪˈtiːk/ |
A careful judgment of something, especially its problems. |
The review offers a critique of the proposed design. |
| drawback |
/ˈdrɔːbæk/ |
A disadvantage or problem with something. |
Cost is the main drawback of this approach. |
Phrases
| Phrase |
Meaning |
Example |
| in the context of |
When considered as part of a particular situation. |
The rule makes sense in the context of a small team. |
2. Isolation Definitions
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| isolation |
/ˌaɪsəˈleɪʃən/ |
Separation that prevents one operation from affecting another. |
Isolation protects one transaction from another transaction’s changes. |
| phenomenon |
/fəˈnɑːmɪnən/ |
A fact or event that can be observed. |
The test revealed an unexpected phenomenon. |
Phrases
| Phrase |
Meaning |
Example |
| be defined in terms of |
Be explained by using a particular idea or measure. |
The requirement is defined in terms of observable behavior. |
2.1 Serializability Concepts
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| serializability |
/ˌsɪəriələˈzəbɪləti/ |
The property that concurrent work has the same result as some serial order. |
Serializability is a strong correctness guarantee. |
| concurrent |
/kənˈkɜːrənt/ |
Happening at the same time. |
Concurrent requests can update the same record. |
Phrases
| Phrase |
Meaning |
Example |
| equivalent to |
Having the same effect, meaning, or value as something else. |
The final state is equivalent to a serial execution. |
2.2 ANSI SQL Isolation Levels
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| anomaly |
/əˈnɑːməli/ |
Something unusual that does not follow the expected pattern. |
The monitor reported an anomaly in the transaction log. |
| prohibited |
/prəˈhɪbɪtɪd/ |
Officially not allowed. |
Direct writes to the table are prohibited. |
Phrases
| Phrase |
Meaning |
Example |
| isolation level |
A defined degree of protection between transactions. |
The application uses a stricter isolation level for payments. |
2.3 Locking
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| locking |
/ˈlɑːkɪŋ/ |
Controlling access to data so conflicting operations cannot happen together. |
Locking prevents two writers from changing the row at once. |
| duration |
/dʊˈreɪʃən/ |
The length of time that something continues. |
The lock duration should be as short as possible. |
Phrases
| Phrase |
Meaning |
Example |
| hold a lock |
Keep exclusive or shared access to data for a period of time. |
The worker holds a lock until the update finishes. |
3. Analyzing ANSI SQL Isolation Levels
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| analyze |
/ˈænəlaɪz/ |
Examine something carefully to understand it. |
Engineers analyze the trace before changing the code. |
| ambiguity |
/ˌæmbɪˈɡjuːəti/ |
A situation where something has more than one possible meaning. |
The wording creates ambiguity for implementers. |
Phrases
| Phrase |
Meaning |
Example |
| give rise to |
Cause something to happen or exist. |
A weak guarantee can give rise to incorrect results. |
4. Other Isolation Types
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| alternative |
/ɔːlˈtɜːrnətɪv/ |
A different choice or method. |
Snapshot isolation is an alternative to locking. |
| implementation |
/ˌɪmplɪmenˈteɪʃən/ |
The process or result of putting a design into use. |
The implementation uses versioned records. |
Phrases
| Phrase |
Meaning |
Example |
| in contrast to |
Compared with something that is different. |
In contrast to a lock, a snapshot does not block readers. |
4.1 Cursor Stability
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| cursor |
/ˈkɜːrsər/ |
A database object used to process query results one row at a time. |
The cursor moves to the next matching row. |
| stability |
/stəˈbɪləti/ |
The quality of remaining unchanged or reliable. |
Cursor stability prevents a row from changing unexpectedly. |
Phrases
| Phrase |
Meaning |
Example |
| current row |
The row that a cursor is currently positioned on. |
The client updates the current row after validation. |
4.2 Snapshot Isolation
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| snapshot |
/ˈsnæpʃɑːt/ |
A view of data at a particular point in time. |
The query reads from a consistent snapshot. |
| conflict |
/ˈkɑːnflɪkt/ |
A situation where two operations cannot both succeed as intended. |
The database rejects the write conflict. |
Phrases
| Phrase |
Meaning |
Example |
| point in time |
One exact moment. |
The report shows the state at a point in time. |
4.3 Other Multi-Version Systems
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| multi-version |
/ˌmʌlti ˈvɜːrʒən/ |
Keeping more than one version of data. |
A multi-version system lets readers see older data safely. |
| obsolete |
/ˌɑːbsəˈliːt/ |
No longer used because something newer exists. |
The cleanup task removes obsolete versions. |
Phrases
| Phrase |
Meaning |
Example |
| retain a version |
Keep a particular version available. |
The system retains a version for active readers. |
5. Summary and Conclusions
Vocabulary
| Word or expression |
IPA |
Simple English meaning |
Example |
| conclusion |
/kənˈkluːʒən/ |
A final decision or opinion reached after considering evidence. |
The experiments support the same conclusion. |
| refinement |
/rɪˈfaɪnmənt/ |
A small improvement that makes something more precise or effective. |
The proposal needs a refinement before adoption. |
Phrases
| Phrase |
Meaning |
Example |
| draw a conclusion |
Form an opinion after considering facts. |
We should not draw a conclusion from one test. |