Truncate the WAL if it exceeds 100MiB

As database performance seems to start to drop off around this point.

1 files changed, 15 insertions, 1 deletions

diff --git a/guix-build-coordinator/datastore/sqlite.scm b/guix-build-coordinator/datastore/sqlite.scm
index f57c54e..d857a31 100644
--- a/guix-build-coordinator/datastore/sqlite.scm
+++ b/guix-build-coordinator/datastore/sqlite.scm
@@ -184,6 +184,18 @@
 
 (define-method (datastore-spawn-fibers
                 (datastore <sqlite-datastore>))
+  (define (wal-size)
+    (let* ((db-filename
+            (slot-ref datastore 'database-file))
+           (db-wal-filename
+            (string-append db-filename "-wal")))
+
+      (stat:size (stat db-wal-filename))))
+
+  (define MiB (* (expt 2 20) 1.))
+  (define wal-size-threshold
+    (* 100 MiB))
+
   (let* ((checkpoint-duration-metric-name
           "datastore_wal_checkpoint_duration_seconds")
          (metrics-registry
@@ -208,7 +220,9 @@
                     metrics-registry
                     checkpoint-duration-metric-name
                     (lambda ()
-                      (sqlite-exec db "PRAGMA wal_checkpoint(RESTART);"))))))
+                      (if (> (wal-size) wal-size-threshold)
+                          (sqlite-exec db "PRAGMA wal_checkpoint(TRUNCATE);")
+                          (sqlite-exec db "PRAGMA wal_checkpoint(RESTART);")))))))
               #:times 5
               #:delay 5))
            #:unwind? #t)))