Use the following code snippet (add error checking, set v_file to the full path
name of your SQLite db file) to check.
It attempts to take the same locks as SQLite would, but prints the pid of the
blocking process. It also prints the journal mode.
#include <sys/types.h>
#include <sys/stat.h>
#ifdef AIX64
#include </usr/include/sys/flock.h>
#endif
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include "sqliteInt.h"
static const char *g_mode[] = {
"[0/0]", "[del]", "[WAL]", "[?/?]"
};
char v_buff[256];
int v_mode;
struct flock v_pending; // = { F_WRLCK, SEEK_SET, PENDING_BYTE ,
1, 0};
struct flock v_reserved; // = { F_WRLCK, SEEK_SET, RESERVED_BYTE ,
1, 0};
struct flock v_shared; // = { F_WRLCK, SEEK_SET, SHARED_FIRST ,
SHARED_SIZE, 0};
int v_fd = -1;
int v_ret = -1;
memset( &v_pending, 0, sizeof( v_pending));
v_pending.l_type = F_WRLCK;
v_pending.l_whence = SEEK_SET;
v_pending.l_start = PENDING_BYTE;
v_pending.l_len = 1;
v_pending.l_pid = 0;
memset( &v_reserved, 0, sizeof( v_reserved));
v_reserved.l_type = F_WRLCK;
v_reserved.l_whence = SEEK_SET;
v_reserved.l_start = RESERVED_BYTE;
v_reserved.l_len = 1;
v_reserved.l_pid = 0;
memset( &v_shared, 0, sizeof( v_shared));
v_shared.l_type = F_WRLCK;
v_shared.l_whence = SEEK_SET;
v_shared.l_start = SHARED_FIRST;
v_shared.l_len = SHARED_SIZE;
v_shared.l_pid = 0;
/* open the file readonly */
v_fd = open(v_file,O_RDONLY);
// read the file header
read(v_fd, v_buff, 100);
// interpret the bytes
switch (v_buff[18]) {
case 0: v_mode = (v_buff[18] == v_buff[19]) ? 0 : 3; break; // empty
case 1: v_mode = (v_buff[18] == v_buff[19]) ? 1 : 3; break; //
journal_mode=delete
case 2: v_mode = (v_buff[18] == v_buff[19]) ? 2 : 3; break; //
journal_mode=wal
default: v_mode = 3; break; // invalid
};
/* check for a PENDING lock */
fcntl(v_fd,F_GETLK,&v_pending);
/* check for a RESERVED lock */
fcntl(v_fd,F_GETLK,&v_reserved);
/* check for a SHARED/EXCLUSIVE lock */
fcntl(v_fd,F_GETLK,&v_shared);
/* print in ascending restrictivity */
if (v_pending.l_type == F_RDLCK)
printf("%s File:%s, Process %d PENDING (SHARED)\n" ,g_mode[v_mode]
,v_file, (v_ret = v_pending .l_pid));
if (v_shared .l_type == F_RDLCK)
printf("%s File:%s, Process %d SHARED\n" ,g_mode[v_mode]
,v_file, (v_ret = v_shared .l_pid));
switch (v_reserved.l_type) {
case F_WRLCK:
case F_RDLCK:
printf("%s File:%s, Process %d RESERVED\n" ,g_mode[v_mode]
,v_file, (v_ret = v_reserved.l_pid));
break;
default: break;
}
if (v_pending.l_type == F_WRLCK)
printf("%s File: %s,Process %d PENDING (EXCLUSIVE)\n",g_mode[v_mode]
,v_file, (v_ret = v_pending .l_pid));
if (v_shared .l_type == F_WRLCK)
printf("%s File %s, Process %d EXCLUSIVE\n" ,g_mode[v_mode]
,v_file, (v_ret = v_shared .l_pid));
if (v_ret == -1)
printf("%s File:%s, <none>\n" ,g_mode[v_mode]
,v_file);
-----Ursprüngliche Nachricht-----
Von: Roman Fleysher [mailto:roman.fleys...@einstein.yu.edu]
Gesendet: Mittwoch, 14. Jänner 2015 18:54
An: General Discussion of SQLite Database
Betreff: Re: [sqlite] database is locked
SQLite shell version 3.7.2
on Linux 2.6.18
NTFS
________________________________________
From: sqlite-users-boun...@sqlite.org<mailto:sqlite-users-boun...@sqlite.org>
[sqlite-users-boun...@sqlite.org] on behalf of Richard Hipp [d...@sqlite.org]
Sent: Wednesday, January 14, 2015 12:50 PM
To: General Discussion of SQLite Database
Subject: Re: [sqlite] database is locked
On 1/14/15, Roman Fleysher
<roman.fleys...@einstein.yu.edu<mailto:roman.fleys...@einstein.yu.edu>> wrote:
> Dear SQLiters,
>
> There has been a lot of discussion, I remember, on this subject by others.
> Please forgive me for asking this for a millionth time.
>
> I somehow got my database in a locked state. I updated a table
> yesterday and I am rather sure that no one on our multi-user system is
> updating it now.
> The time stamp on the file is from yesterday, showing correct time. I
> need to update a table (I use shell) and I get "database is locked".
> Is there a way to figure out what is happening? Clear the lock?
What operating system and filesystem are you using? And are you specifying an
alternative VFS for SQLite or using the default?
>
> Thank you for your help,
>
> Roman
> _______________________________________________
> sqlite-users mailing list
> sqlite-users@sqlite.org<mailto:sqlite-users@sqlite.org>
> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
>
--
D. Richard Hipp
d...@sqlite.org<mailto:d...@sqlite.org>
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___________________________________________
Gunter Hick
Software Engineer
Scientific Games International GmbH
FN 157284 a, HG Wien
Klitschgasse 2-4, A-1130 Vienna, Austria
Tel: +43 1 80100 0
E-Mail: h...@scigames.at
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