1 /*
2 ** 2001 September 15
3 **
4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
6 **
7 ** May you do good and not evil.
8 ** May you find forgiveness for yourself and forgive others.
9 ** May you share freely, never taking more than you give.
10 **
11 *************************************************************************
12 ** This file is part of the test program "threadtest3". Despite being a C
13 ** file it is not compiled separately, but included by threadtest3.c using
14 ** the #include directive normally used with header files.
15 **
16 ** This file contains the implementation of test cases:
17 **
18 ** checkpoint_starvation_1
19 ** checkpoint_starvation_2
20 */
21
22 /*
23 ** Both test cases involve 1 writer/checkpointer thread and N reader threads.
24 **
25 ** Each reader thread performs a series of read transactions, one after
26 ** another. Each read transaction lasts for 100 ms.
27 **
28 ** The writer writes transactions as fast as possible. It uses a callback
29 ** registered with sqlite3_wal_hook() to try to keep the WAL-size limited to
30 ** around 50 pages.
31 **
32 ** In test case checkpoint_starvation_1, the auto-checkpoint uses
33 ** SQLITE_CHECKPOINT_PASSIVE. In checkpoint_starvation_2, it uses RESTART.
34 ** The expectation is that in the first case the WAL file will grow very
35 ** large, and in the second will be limited to the 50 pages or thereabouts.
36 ** However, the overall transaction throughput will be lower for
37 ** checkpoint_starvation_2, as every checkpoint will block for up to 200 ms
38 ** waiting for readers to clear.
39 */
40
41 /* Frame limit used by the WAL hook for these tests. */
42 #define CHECKPOINT_STARVATION_FRAMELIMIT 50
43
44 /* Duration in ms of each read transaction */
45 #define CHECKPOINT_STARVATION_READMS 100
46
47 struct CheckpointStarvationCtx {
48 int eMode;
49 int nMaxFrame;
50 };
51 typedef struct CheckpointStarvationCtx CheckpointStarvationCtx;
52
checkpoint_starvation_walhook(void * pCtx,sqlite3 * db,const char * zDb,int nFrame)53 static int checkpoint_starvation_walhook(
54 void *pCtx,
55 sqlite3 *db,
56 const char *zDb,
57 int nFrame
58 ){
59 CheckpointStarvationCtx *p = (CheckpointStarvationCtx *)pCtx;
60 if( nFrame>p->nMaxFrame ){
61 p->nMaxFrame = nFrame;
62 }
63 if( nFrame>=CHECKPOINT_STARVATION_FRAMELIMIT ){
64 sqlite3_wal_checkpoint_v2(db, zDb, p->eMode, 0, 0);
65 }
66 return SQLITE_OK;
67 }
68
checkpoint_starvation_reader(int iTid,int iArg)69 static char *checkpoint_starvation_reader(int iTid, int iArg){
70 Error err = {0};
71 Sqlite db = {0};
72
73 opendb(&err, &db, "test.db", 0);
74 while( !timetostop(&err) ){
75 i64 iCount1, iCount2;
76 sql_script(&err, &db, "BEGIN");
77 iCount1 = execsql_i64(&err, &db, "SELECT count(x) FROM t1");
78 usleep(CHECKPOINT_STARVATION_READMS*1000);
79 iCount2 = execsql_i64(&err, &db, "SELECT count(x) FROM t1");
80 sql_script(&err, &db, "COMMIT");
81
82 if( iCount1!=iCount2 ){
83 test_error(&err, "Isolation failure - %lld %lld", iCount1, iCount2);
84 }
85 }
86 closedb(&err, &db);
87
88 print_and_free_err(&err);
89 return 0;
90 }
91
checkpoint_starvation_main(int nMs,CheckpointStarvationCtx * p)92 static void checkpoint_starvation_main(int nMs, CheckpointStarvationCtx *p){
93 Error err = {0};
94 Sqlite db = {0};
95 Threadset threads = {0};
96 int nInsert = 0;
97 int i;
98
99 opendb(&err, &db, "test.db", 1);
100 sql_script(&err, &db,
101 "PRAGMA page_size = 1024;"
102 "PRAGMA journal_mode = WAL;"
103 "CREATE TABLE t1(x);"
104 );
105
106 setstoptime(&err, nMs);
107
108 for(i=0; i<4; i++){
109 launch_thread(&err, &threads, checkpoint_starvation_reader, 0);
110 usleep(CHECKPOINT_STARVATION_READMS*1000/4);
111 }
112
113 sqlite3_wal_hook(db.db, checkpoint_starvation_walhook, (void *)p);
114 while( !timetostop(&err) ){
115 sql_script(&err, &db, "INSERT INTO t1 VALUES(randomblob(1200))");
116 nInsert++;
117 }
118
119 printf(" Checkpoint mode : %s\n",
120 p->eMode==SQLITE_CHECKPOINT_PASSIVE ? "PASSIVE" : "RESTART"
121 );
122 printf(" Peak WAL : %d frames\n", p->nMaxFrame);
123 printf(" Transaction count: %d transactions\n", nInsert);
124
125 join_all_threads(&err, &threads);
126 closedb(&err, &db);
127 print_and_free_err(&err);
128 }
129
checkpoint_starvation_1(int nMs)130 static void checkpoint_starvation_1(int nMs){
131 Error err = {0};
132 CheckpointStarvationCtx ctx = { SQLITE_CHECKPOINT_PASSIVE, 0 };
133 checkpoint_starvation_main(nMs, &ctx);
134 if( ctx.nMaxFrame<(CHECKPOINT_STARVATION_FRAMELIMIT*10) ){
135 test_error(&err, "WAL failed to grow - %d frames", ctx.nMaxFrame);
136 }
137 print_and_free_err(&err);
138 }
139
checkpoint_starvation_2(int nMs)140 static void checkpoint_starvation_2(int nMs){
141 Error err = {0};
142 CheckpointStarvationCtx ctx = { SQLITE_CHECKPOINT_RESTART, 0 };
143 checkpoint_starvation_main(nMs, &ctx);
144 if( ctx.nMaxFrame>CHECKPOINT_STARVATION_FRAMELIMIT+10 ){
145 test_error(&err, "WAL grew too large - %d frames", ctx.nMaxFrame);
146 }
147 print_and_free_err(&err);
148 }
149
150
151