45 lines
1.2 KiB
Markdown
45 lines
1.2 KiB
Markdown
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LOCK statement obtains a table-level lock, waiting if necessary for any conflicting locks to be released.
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More about LOCK statement in PostgreSQL: https://www.postgresql.org/docs/11/sql-lock.html
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Following clauses are supported:
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- IN(mode) - mode specifies which locks this lock conflicts with.
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Mode can be:
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- jet.LOCK_ACCESS_SHARE
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- jet.LOCK_ROW_SHARE
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- jet.LOCK_ROW_EXCLUSIVE
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- jet.LOCK_SHARE_UPDATE_EXCLUSIVE
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- jet.LOCK_SHARE
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- jet.LOCK_SHARE_ROW_EXCLUSIVE
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- jet.LOCK_EXCLUSIVE
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- jet.LOCK_ACCESS_EXCLUSIVE
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- NOWAIT() - locked table should not wait for any conflicting locks to be released. If the specified lock(s)
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cannot be acquired immediately without waiting, the transaction is aborted.
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## Example
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```
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lockStmt := Address.
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LOCK().
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IN(jet.LOCK_ACCESS_SHARE).
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NOWAIT()
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```
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Debug SQL of above statement:
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```sql
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LOCK TABLE dvds.address IN ACCESS SHARE MODE NOWAIT;
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```
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### Execute statement
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To execute update statement and get sql.Result:
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```
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res, err := lockStmt.Exec(db)
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```
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Use `ExecContext` to provide context object to execution.
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