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From: |
Ludovic Courtès |
Date: |
Fri, 26 Jan 2018 12:29:53 -0500 (EST) |
branch: master
commit f3335e880c26897daced684710de7d79f5a83252
Author: Ludovic Courtès <address@hidden>
Date: Fri Jan 26 18:20:30 2018 +0100
database: Open the database in "write-ahead log" mode.
Suggested by Ricardo Wurmus.
* src/cuirass/database.scm (wal-mode): New procedure.
(db-open): Use it.
---
src/cuirass/database.scm | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/src/cuirass/database.scm b/src/cuirass/database.scm
index f1d0118..5ca3ad3 100644
--- a/src/cuirass/database.scm
+++ b/src/cuirass/database.scm
@@ -99,6 +99,11 @@ SQL statement to DB. FMT and ARGS are passed to 'format'."
(reverse! insts)
(loop (cons inst insts))))))))
+(define (wal-mode db)
+ "Turn DB in \"write-ahead log\" mode and return it."
+ (sqlite-exec db "PRAGMA journal_mode=WAL;")
+ db)
+
(define* (db-init #:optional (db-name (%package-database))
#:key (schema (%package-schema-file)))
"Open the database to store and read jobs and builds informations. Return a
@@ -115,9 +120,12 @@ database object."
(define* (db-open #:optional (db (%package-database)))
"Open database to store or read jobs and builds informations. Return a
database object."
- (if (file-exists? db)
- (sqlite-open db SQLITE_OPEN_READWRITE)
- (db-init db)))
+ ;; Use "write-ahead log" mode because it improves concurrency and should
+ ;; avoid SQLITE_LOCKED errors when we have several readers:
+ ;; <https://www.sqlite.org/wal.html>.
+ (wal-mode (if (file-exists? db)
+ (sqlite-open db SQLITE_OPEN_READWRITE)
+ (db-init db))))
(define (db-close db)
"Close database object DB."