Index-only scan: return `(doc_id, field_value)` pairs without touching DOCUMENTS.
(
&self,
tenant_id: u64,
collection: &str,
field: &str,
limit: usize,
)
| 344 | |
| 345 | /// Index-only scan: return `(doc_id, field_value)` pairs without touching DOCUMENTS. |
| 346 | pub fn scan_index_values( |
| 347 | &self, |
| 348 | tenant_id: u64, |
| 349 | collection: &str, |
| 350 | field: &str, |
| 351 | limit: usize, |
| 352 | ) -> crate::Result<Vec<(String, String)>> { |
| 353 | let prefix = format!("{tenant_id}:{collection}:{field}:"); |
| 354 | let end = format!("{tenant_id}:{collection}:{field}:\u{ffff}"); |
| 355 | |
| 356 | let read_txn = self.db.begin_read().map_err(|e| redb_err("read txn", e))?; |
| 357 | let table = read_txn |
| 358 | .open_table(INDEXES) |
| 359 | .map_err(|e| redb_err("open table", e))?; |
| 360 | |
| 361 | let range = table |
| 362 | .range(prefix.as_str()..end.as_str()) |
| 363 | .map_err(|e| redb_err("index range", e))?; |
| 364 | |
| 365 | let mut results = Vec::with_capacity(limit.min(256)); |
| 366 | for entry in range { |
| 367 | if results.len() >= limit { |
| 368 | break; |
| 369 | } |
| 370 | let entry = entry.map_err(|e| redb_err("index entry", e))?; |
| 371 | let key = entry.0.value().to_string(); |
| 372 | if let Some(rest) = key.strip_prefix(&prefix) |
| 373 | && let Some(colon_pos) = rest.rfind(':') |
| 374 | { |
| 375 | let value = &rest[..colon_pos]; |
| 376 | let doc_id = &rest[colon_pos + 1..]; |
| 377 | results.push((doc_id.to_string(), value.to_string())); |
| 378 | } |
| 379 | } |
| 380 | |
| 381 | debug!(collection, field, count = results.len(), "index-only scan"); |
| 382 | Ok(results) |
| 383 | } |
| 384 | |
| 385 | /// Insert a document by raw pre-formed key (snapshot restore). |
| 386 | pub fn put_raw(&self, key: &str, value: &[u8]) -> crate::Result<()> { |