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Removed memory limit debug message from HNSW index scans (EXPLAIN ANALYZE can be used instead)

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This commit is contained in:
Andrew Kane
2024-10-28 13:46:49 -07:00
parent 2f770307b8
commit a2a0b377f0
2 changed files with 3 additions and 29 deletions
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13
README.md
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@@ -537,18 +537,7 @@ Specify the max amount of memory to use, as a multiple of `work_mem` (1 by defau
SET hnsw.scan_mem_multiplier = 2; SET hnsw.scan_mem_multiplier = 2;
``` ```
You can see when increasing this is needed by enabling debug messages Note: Try increasing this if increasing `hnsw.max_scan_tuples` does not improve recall
```sql
SET client_min_messages = debug1;
```
which will show when a scan reaches the memory limit
```text
DEBUG: hnsw index scan reached memory limit after 20000 tuples
HINT: Increase hnsw.scan_mem_multiplier to scan more tuples.
```
#### IVFFlat #### IVFFlat

19
src/hnswscan.c
View File

@@ -240,8 +240,8 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)
if (so->discarded == NULL) if (so->discarded == NULL)
break; break;
/* Reached max number of tuples */ /* Reached max number of tuples or memory limit */
if (so->tuples >= hnsw_max_scan_tuples) if (so->tuples >= hnsw_max_scan_tuples || MemoryContextMemAllocated(so->tmpCtx, false) > so->maxMemory)
{ {
if (pairingheap_is_empty(so->discarded)) if (pairingheap_is_empty(so->discarded))
break; break;
@@ -249,21 +249,6 @@ hnswgettuple(IndexScanDesc scan, ScanDirection dir)
/* Return remaining tuples */ /* Return remaining tuples */
so->w = lappend(so->w, HnswGetSearchCandidate(w_node, pairingheap_remove_first(so->discarded))); so->w = lappend(so->w, HnswGetSearchCandidate(w_node, pairingheap_remove_first(so->discarded)));
} }
/* Prevent scans from consuming too much memory */
else if (MemoryContextMemAllocated(so->tmpCtx, false) > so->maxMemory)
{
if (pairingheap_is_empty(so->discarded))
{
ereport(DEBUG1,
(errmsg("hnsw index scan reached memory limit after " INT64_FORMAT " tuples", so->tuples),
errhint("Increase hnsw.scan_mem_multiplier to scan more tuples.")));
break;
}
/* Return remaining tuples */
so->w = lappend(so->w, HnswGetSearchCandidate(w_node, pairingheap_remove_first(so->discarded)));
}
else else
{ {
/* /*