Try to fix sqlite3 blocking.

Issue: #331

diff --git a/src/libstat/learn_cache/sqlite3_cache.c b/src/libstat/learn_cache/sqlite3_cache.c
index 017ee61088d96b6c039f3947d73f8d836109e2cf..a9e74edbbde0322e6a4a3a07d2ecd50059afc402 100644 (file)
--- a/src/libstat/learn_cache/sqlite3_cache.c
+++ b/src/libstat/learn_cache/sqlite3_cache.c
@@ -33,7 +33,7 @@
 #include <sqlite3.h>
 
 static const char *create_tables_sql =
-               "BEGIN;"
+               "BEGIN IMMEDIATE;"
                "CREATE TABLE IF NOT EXISTS learns("
                "id INTEGER PRIMARY KEY,"
                "flag INTEGER NOT NULL,"
@@ -54,11 +54,13 @@ rspamd_stat_cache_sqlite3_init(struct rspamd_stat_ctx *ctx,
        struct rspamd_stat_sqlite3_ctx *new = NULL;
        struct rspamd_classifier_config *clf;
        const ucl_object_t *obj, *elt;
+       static const char sqlite_wal[] = "PRAGMA journal_mode=WAL;",
+                       fallback_journal[] = "PRAGMA journal_mode=OFF;";
        GList *cur;
        gchar dbpath[PATH_MAX];
        sqlite3 *sqlite;
        gboolean has_sqlite_cache = FALSE;
-       gint rc;
+       gint rc, fd;
 
        rspamd_snprintf (dbpath, sizeof (dbpath), SQLITE_CACHE_PATH);
        cur = cfg->classifiers;
@@ -93,19 +95,29 @@ rspamd_stat_cache_sqlite3_init(struct rspamd_stat_ctx *ctx,
 
        if (has_sqlite_cache) {
                if ((rc = sqlite3_open_v2 (dbpath, &sqlite,
-                               SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_NOMUTEX, NULL))
+                               SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE, NULL))
                                != SQLITE_OK) {
-                       msg_err ("Cannot open sqlite db %s: %s", SQLITE_CACHE_PATH,
+                       msg_err ("Cannot open sqlite db %s: %s", dbpath,
                                        sqlite3_errmsg (sqlite));
 
                        return NULL;
                }
+               else {
+                       msg_debug ("opened sqlite cache at the path %s", dbpath);
+               }
+
+               if (sqlite3_exec (sqlite, sqlite_wal, NULL, NULL, NULL) != SQLITE_OK) {
+                       msg_warn ("WAL mode is not supported, locking issues might occur");
+                       sqlite3_exec (sqlite, fallback_journal, NULL, NULL, NULL);
+               }
 
                if ((rc = sqlite3_exec (sqlite, create_tables_sql, NULL, NULL, NULL))
                                != SQLITE_OK) {
                        msg_err ("Cannot initialize sqlite db %s: %s", SQLITE_CACHE_PATH,
                                        sqlite3_errmsg (sqlite));
                        sqlite3_close (sqlite);
+                       rspamd_file_unlock (fd, FALSE);
+                       close (fd);
 
                        return NULL;
                }
@@ -122,9 +134,14 @@ rspamd_stat_cache_sqlite3_check (const guchar *h, gsize len, gboolean is_spam,
                struct rspamd_stat_sqlite3_ctx *ctx)
 {
        static const gchar select_sql[] = "SELECT flag FROM learns WHERE digest=?1";
-       static const gchar insert_sql[] = "INSERT INTO learns(digest, flag) VALUES "
-                               "(?1, ?2);";
-       static const gchar update_sql[] = "UPDATE learns SET flag=?1 WHERE digest=?2";
+       static const gchar insert_sql[] = ""
+                       ""
+                       "INSERT INTO learns(digest, flag) VALUES (?1, ?2);"
+                       "";
+       static const gchar update_sql[] = ""
+                       ""
+                       "UPDATE learns SET flag=?1 WHERE digest=?2;"
+                       "";
        sqlite3_stmt *st = NULL;
        gint rc, ret = RSPAMD_LEARN_OK, flag;
 
@@ -151,34 +168,48 @@ rspamd_stat_cache_sqlite3_check (const guchar *h, gsize len, gboolean is_spam,
                        /* Need to relearn */
                        if ((rc = sqlite3_prepare_v2 (ctx->db, update_sql,
                                        -1, &st, NULL)) != SQLITE_OK) {
-                               msg_err ("Cannot prepare sql %s: %s", update_sql,
+                               msg_err ("cannot prepare sql %s: %s", update_sql,
                                                sqlite3_errmsg (ctx->db));
                        }
                        else {
                                sqlite3_bind_int (st, 1, is_spam ? 1 : 0);
                                sqlite3_bind_text (st, 2, h, len, SQLITE_STATIC);
-                               sqlite3_step (st);
+
+                               if ((rc = sqlite3_step (st)) != SQLITE_DONE) {
+                                       msg_err ("error during executing sql %s: %s", update_sql,
+                                                       sqlite3_errmsg (ctx->db));
+                               }
+
                                sqlite3_finalize (st);
                        }
 
                        return RSPAMD_LEARN_UNLEARN;
                }
        }
-       else {
+       else if (rc != SQLITE_ERROR && rc != SQLITE_BUSY) {
                /* Insert result new id */
                sqlite3_finalize (st);
                if ((rc = sqlite3_prepare_v2 (ctx->db, insert_sql,
                                -1, &st, NULL)) != SQLITE_OK) {
-                       msg_err ("Cannot prepare sql %s: %s", insert_sql,
+                       msg_err ("cannot prepare sql %s: %s", insert_sql,
                                        sqlite3_errmsg (ctx->db));
                }
                else {
                        sqlite3_bind_text (st, 1, h, len, SQLITE_STATIC);
                        sqlite3_bind_int (st, 2, is_spam ? 1 : 0);
-                       sqlite3_step (st);
+
+                       if ((rc = sqlite3_step (st)) != SQLITE_DONE) {
+                               msg_err ("error during executing sql %s: %s", insert_sql,
+                                               sqlite3_errmsg (ctx->db));
+                       }
+
                        sqlite3_finalize (st);
                }
        }
+       else {
+               msg_err ("error during executing sql %s: %s", select_sql,
+                               sqlite3_errmsg (ctx->db));
+       }
 
        return ret;
 }