SnapshotQuery adds conditions to a SELECT query for checking transaction visibility based on created and expired transaction IDs. Optimized version with parameterized queries for security.
(sl squirrel.SelectBuilder, value uint64, snapshotValue string)
| 39 | // SnapshotQuery adds conditions to a SELECT query for checking transaction visibility based on created and expired transaction IDs. |
| 40 | // Optimized version with parameterized queries for security. |
| 41 | func SnapshotQuery(sl squirrel.SelectBuilder, value uint64, snapshotValue string) squirrel.SelectBuilder { |
| 42 | // Backward compatibility: if snapshot is empty, use old method |
| 43 | if snapshotValue == "" { |
| 44 | // Create a subquery for the snapshot associated with the provided value. |
| 45 | snapshotQuery := "(select snapshot from transactions where id = ?::xid8)" |
| 46 | |
| 47 | // Records that were created and are visible in the snapshot |
| 48 | createdWhere := squirrel.Or{ |
| 49 | squirrel.Expr("pg_visible_in_snapshot(created_tx_id, ?) = true", squirrel.Expr(snapshotQuery, value)), |
| 50 | squirrel.Expr("created_tx_id = ?::xid8", value), // Include current transaction |
| 51 | } |
| 52 | |
| 53 | // Records that are still active (not expired) at snapshot time |
| 54 | expiredWhere := squirrel.And{ |
| 55 | squirrel.Or{ |
| 56 | squirrel.Expr("pg_visible_in_snapshot(expired_tx_id, ?) = false", squirrel.Expr(snapshotQuery, value)), |
| 57 | squirrel.Expr("expired_tx_id = ?::xid8", ActiveRecordTxnID), // Never expired |
| 58 | }, |
| 59 | squirrel.Expr("expired_tx_id <> ?::xid8", value), // Not expired by current transaction |
| 60 | } |
| 61 | |
| 62 | // Add the created and expired conditions to the SELECT query. |
| 63 | return sl.Where(createdWhere).Where(expiredWhere) |
| 64 | } |
| 65 | |
| 66 | // Records that were created and are visible in the snapshot |
| 67 | createdWhere := squirrel.Or{ |
| 68 | squirrel.Expr("pg_visible_in_snapshot(created_tx_id, ?) = true", snapshotValue), |
| 69 | squirrel.Expr("created_tx_id = ?::xid8", value), // Include current transaction |
| 70 | } |
| 71 | |
| 72 | // Records that are still active (not expired) at snapshot time |
| 73 | expiredWhere := squirrel.And{ |
| 74 | squirrel.Or{ |
| 75 | squirrel.Expr("pg_visible_in_snapshot(expired_tx_id, ?) = false", snapshotValue), |
| 76 | squirrel.Expr("expired_tx_id = ?::xid8", ActiveRecordTxnID), // Never expired |
| 77 | }, |
| 78 | squirrel.Expr("expired_tx_id <> ?::xid8", value), // Not expired by current transaction |
| 79 | } |
| 80 | |
| 81 | // Add the created and expired conditions to the SELECT query. |
| 82 | return sl.Where(createdWhere).Where(expiredWhere) |
| 83 | } |
| 84 | |
| 85 | // GenerateGCQuery generates a Squirrel DELETE query builder for garbage collection. |
| 86 | // It constructs a query to delete expired records from the specified table |
no outgoing calls
no test coverage detected