lib/logstorage: always check the previous indexBlockHeader for blocks…

… with matching tenantID and/or streamID

The previous indexBlockHeader may contain blocks for the matching tenantID and/or streamID,
so it must be scanned unconditionally during the search.

Updates #5295
Updates #4856

This is a follow-up for 89dcbc2

docs/VictoriaLogs/CHANGELOG.md

@@ -18,6 +18,7 @@ according to [these docs](https://docs.victoriametrics.com/VictoriaLogs/QuickSta
 
 ## tip
 
+* BUGFIX: properly locate logs for the [requested streams](https://docs.victoriametrics.com/VictoriaLogs/LogsQL.html#stream-filter). Previously logs for some streams may be missing in query results. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/4856). Thanks to @XLONG96 for [the fix](https://github.com/VictoriaMetrics/VictoriaMetrics/pull/5295)!
 * BUGFIX: [web UI](https://docs.victoriametrics.com/VictoriaLogs/querying/#web-ui): properly sort found logs by time. See [this issue](https://github.com/VictoriaMetrics/VictoriaMetrics/issues/5300).
 
 

lib/logstorage/storage_search.go

@@ -382,10 +382,8 @@ func (p *part) searchByTenantIDs(so *searchOptions, bhss *blockHeaders, workCh c
 			n = sort.Search(len(ibhs), func(i int) bool {
 				return !ibhs[i].streamID.tenantID.less(tenantID)
 			})
-			if n == len(ibhs) || n > 0 && !ibhs[n].streamID.tenantID.equal(tenantID) {
-				// The end of ibhs[n-1] may contain blocks for the given tenantID, so move it backwards
-				n--
-			}
+			// The end of ibhs[n-1] may contain blocks for the given tenantID, so move it backwards
+			n--
 		}
 		ibh := &ibhs[n]
 		ibhs = ibhs[n+1:]
@@ -493,10 +491,8 @@ func (p *part) searchByStreamIDs(so *searchOptions, bhss *blockHeaders, workCh c
 			n = sort.Search(len(ibhs), func(i int) bool {
 				return !ibhs[i].streamID.less(streamID)
 			})
-			if n == len(ibhs) || n > 0 && !ibhs[n].streamID.equal(streamID) {
-				// The end of ibhs[n-1] may contain blocks for the given streamID, so move it backwards
-				n--
-			}
+			// The end of ibhs[n-1] may contain blocks for the given streamID, so move it backwards.
+			n--
 		}
 		ibh := &ibhs[n]
 		ibhs = ibhs[n+1:]