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Example of how to create a row iterator using pg-cursor
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| const createIterator = async (sql, batchSize = 100) => { | |
| const client = await pool.connect() | |
| const cursor = client.query(new Cursor(sql)) | |
| return (async function getRows(client, cursor, batchSize) { | |
| let done = false | |
| // Get next rows | |
| const rows = await new Promise((resolve, reject) => | |
| cursor.read( | |
| batchSize, | |
| (err, rows) => err ? reject(err) : resolve(rows) | |
| ) | |
| ) | |
| // Check if iteration is finished | |
| if (rows.length < 1) { | |
| done = true | |
| cursor.close(() => client.release()) | |
| } | |
| // Return the iterator | |
| return { | |
| done, | |
| rows, | |
| next: async () => await getRows(client, cursor, batchSize) | |
| } | |
| })(client, cursor, batchSize) | |
| } | |
| // Used like so: | |
| let iterator = await createIterator ('select ... from ...', 200) | |
| while (!iterator.done) { | |
| let rows = iterator.rows | |
| // do stuff with rows | |
| iterator = await rowIterator.next() | |
| } |
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