/ Check-in [82268a2c]
Login
SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Added the sqlite3_soft_heap_limit64() interface. Deprecate the older sqlite3_soft_heap_limit() interface.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 82268a2c3d75431cd40de6ad09d398729de32a29
User & Date: drh 2010-09-15 17:54:31
Context
2010-09-15
19:02
Add tests for ORDER BY clauses to e_select.test. check-in: 14f15663 user: dan tags: trunk
17:54
Added the sqlite3_soft_heap_limit64() interface. Deprecate the older sqlite3_soft_heap_limit() interface. check-in: 82268a2c user: drh tags: trunk
11:42
Add trivial test case to make sure shared-cache mode does not automatically turn on exclusive-locking mode. check-in: a0ab3902 user: dan tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to src/malloc.c.

11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
...
110
111
112
113
114
115
116











































































117
118
119
120
121
122
123
...
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
*************************************************************************
**
** Memory allocation functions used throughout sqlite.
*/
#include "sqliteInt.h"
#include <stdarg.h>

/*
** This routine runs when the memory allocator sees that the
** total memory allocation is about to exceed the soft heap
** limit.
*/
static void softHeapLimitEnforcer(
  void *NotUsed, 
  sqlite3_int64 NotUsed2,
  int allocSize
){
  UNUSED_PARAMETER2(NotUsed, NotUsed2);
  sqlite3_release_memory(allocSize);
}

/*
** Set the soft heap-size limit for the library. Passing a zero or 
** negative value indicates no limit.
*/
void sqlite3_soft_heap_limit(int n){
  sqlite3_uint64 iLimit;
  int overage;
  if( n<0 ){
    iLimit = 0;
  }else{
    iLimit = n;
  }
#ifndef SQLITE_OMIT_AUTOINIT
  sqlite3_initialize();
#endif
  if( iLimit>0 ){
    sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, iLimit);
  }else{
    sqlite3MemoryAlarm(0, 0, 0);
  }
  overage = (int)(sqlite3_memory_used() - (i64)n);
  if( overage>0 ){
    sqlite3_release_memory(overage);
  }
}

/*
** Attempt to release up to n bytes of non-essential memory currently
** held by SQLite. An example of non-essential memory is memory used to
** cache database pages that are not currently in use.
*/
int sqlite3_release_memory(int n){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
................................................................................
  ** True if heap is nearly "full" where "full" is defined by the
  ** sqlite3_soft_heap_limit() setting.
  */
  int nearlyFull;
} mem0 = { 0, 0, 0, 0, 0, 0, 0 };

#define mem0 GLOBAL(struct Mem0Global, mem0)












































































/*
** Initialize the memory allocation subsystem.
*/
int sqlite3MallocInit(void){
  if( sqlite3GlobalConfig.m.xMalloc==0 ){
    sqlite3MemSetDefault();
................................................................................
  int n, mx;
  sqlite3_int64 res;
  sqlite3_status(SQLITE_STATUS_MEMORY_USED, &n, &mx, resetFlag);
  res = (sqlite3_int64)mx;  /* Work around bug in Borland C. Ticket #3216 */
  return res;
}

/*
** Change the alarm callback
*/
int sqlite3MemoryAlarm(
  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
  void *pArg,
  sqlite3_int64 iThreshold
){
  int nUsed;
  sqlite3_mutex_enter(mem0.mutex);
  mem0.alarmCallback = xCallback;
  mem0.alarmArg = pArg;
  mem0.alarmThreshold = iThreshold;
  nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
  mem0.nearlyFull = (iThreshold>0 && iThreshold<=nUsed);
  sqlite3_mutex_leave(mem0.mutex);
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_DEPRECATED
/*
** Deprecated external interface.  Internal/core SQLite code
** should call sqlite3MemoryAlarm.
*/
int sqlite3_memory_alarm(
  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
  void *pArg,
  sqlite3_int64 iThreshold
){
  return sqlite3MemoryAlarm(xCallback, pArg, iThreshold);
}
#endif

/*
** Trigger the alarm 
*/
static void sqlite3MallocAlarm(int nByte){
  void (*xCallback)(void*,sqlite3_int64,int);
  sqlite3_int64 nowUsed;
  void *pArg;







<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<







 







>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







 







<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<
<







11
12
13
14
15
16
17








































18
19
20
21
22
23
24
..
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
...
231
232
233
234
235
236
237

































238
239
240
241
242
243
244
*************************************************************************
**
** Memory allocation functions used throughout sqlite.
*/
#include "sqliteInt.h"
#include <stdarg.h>









































/*
** Attempt to release up to n bytes of non-essential memory currently
** held by SQLite. An example of non-essential memory is memory used to
** cache database pages that are not currently in use.
*/
int sqlite3_release_memory(int n){
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
................................................................................
  ** True if heap is nearly "full" where "full" is defined by the
  ** sqlite3_soft_heap_limit() setting.
  */
  int nearlyFull;
} mem0 = { 0, 0, 0, 0, 0, 0, 0 };

#define mem0 GLOBAL(struct Mem0Global, mem0)

/*
** This routine runs when the memory allocator sees that the
** total memory allocation is about to exceed the soft heap
** limit.
*/
static void softHeapLimitEnforcer(
  void *NotUsed, 
  sqlite3_int64 NotUsed2,
  int allocSize
){
  UNUSED_PARAMETER2(NotUsed, NotUsed2);
  sqlite3_release_memory(allocSize);
}

/*
** Change the alarm callback
*/
static int sqlite3MemoryAlarm(
  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
  void *pArg,
  sqlite3_int64 iThreshold
){
  int nUsed;
  sqlite3_mutex_enter(mem0.mutex);
  mem0.alarmCallback = xCallback;
  mem0.alarmArg = pArg;
  mem0.alarmThreshold = iThreshold;
  nUsed = sqlite3StatusValue(SQLITE_STATUS_MEMORY_USED);
  mem0.nearlyFull = (iThreshold>0 && iThreshold<=nUsed);
  sqlite3_mutex_leave(mem0.mutex);
  return SQLITE_OK;
}

#ifndef SQLITE_OMIT_DEPRECATED
/*
** Deprecated external interface.  Internal/core SQLite code
** should call sqlite3MemoryAlarm.
*/
int sqlite3_memory_alarm(
  void(*xCallback)(void *pArg, sqlite3_int64 used,int N),
  void *pArg,
  sqlite3_int64 iThreshold
){
  return sqlite3MemoryAlarm(xCallback, pArg, iThreshold);
}
#endif

/*
** Set the soft heap-size limit for the library. Passing a zero or 
** negative value indicates no limit.
*/
sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 n){
  sqlite3_int64 priorLimit;
  sqlite3_int64 excess;
#ifndef SQLITE_OMIT_AUTOINIT
  sqlite3_initialize();
#endif
  sqlite3_mutex_enter(mem0.mutex);
  priorLimit = mem0.alarmThreshold;
  sqlite3_mutex_leave(mem0.mutex);
  if( n<0 ) return priorLimit;
  if( n>0 ){
    sqlite3MemoryAlarm(softHeapLimitEnforcer, 0, n);
  }else{
    sqlite3MemoryAlarm(0, 0, 0);
  }
  excess = sqlite3_memory_used() - n;
  if( excess>0 ) sqlite3_release_memory(excess & 0x7fffffff);
  return priorLimit;
}
void sqlite3_soft_heap_limit(int n){
  if( n<0 ) n = 0;
  sqlite3_soft_heap_limit64(n);
}

/*
** Initialize the memory allocation subsystem.
*/
int sqlite3MallocInit(void){
  if( sqlite3GlobalConfig.m.xMalloc==0 ){
    sqlite3MemSetDefault();
................................................................................
  int n, mx;
  sqlite3_int64 res;
  sqlite3_status(SQLITE_STATUS_MEMORY_USED, &n, &mx, resetFlag);
  res = (sqlite3_int64)mx;  /* Work around bug in Borland C. Ticket #3216 */
  return res;
}


































/*
** Trigger the alarm 
*/
static void sqlite3MallocAlarm(int nByte){
  void (*xCallback)(void*,sqlite3_int64,int);
  sqlite3_int64 nowUsed;
  void *pArg;

Changes to src/sqlite.h.in.

1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
....
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909



3910
3911
3912
3913
3914
3915
3916
....
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151


4152
4153
4154
4155
4156
4157

4158
4159
4160
4161
4162
4163
4164



















4165











4166

4167
4168
4169
4170
4171
4172
4173
** <dd> ^This option takes single argument of type int, interpreted as a 
** boolean, which enables or disables the collection of memory allocation 
** statistics. ^(When memory allocation statistics are disabled, the 
** following SQLite interfaces become non-operational:
**   <ul>
**   <li> [sqlite3_memory_used()]
**   <li> [sqlite3_memory_highwater()]
**   <li> [sqlite3_soft_heap_limit()]
**   <li> [sqlite3_status()]
**   </ul>)^
** ^Memory allocation statistics are enabled by default unless SQLite is
** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
** allocation statistics are disabled by default.
** </dd>
**
................................................................................
  const char *zPassPhrase        /* Activation phrase */
);
#endif

/*
** CAPI3REF: Suspend Execution For A Short Time
**
** ^The sqlite3_sleep() function causes the current thread to suspend execution
** for at least a number of milliseconds specified in its parameter.
**
** ^If the operating system does not support sleep requests with
** millisecond time resolution, then the time will be rounded up to
** the nearest second. ^The number of milliseconds of sleep actually
** requested from the operating system is returned.
**
** ^SQLite implements this interface by calling the xSleep()
** method of the default [sqlite3_vfs] object.



*/
int sqlite3_sleep(int);

/*
** CAPI3REF: Name Of The Folder Holding Temporary Files
**
** ^(If this global variable is made to point to a string which is
................................................................................
** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
*/
int sqlite3_release_memory(int);

/*
** CAPI3REF: Impose A Limit On Heap Size
**
** ^The sqlite3_soft_heap_limit() interface places a "soft" limit
** on the amount of heap memory that may be allocated by SQLite.
** ^If an internal allocation is requested that would exceed the
** soft heap limit, [sqlite3_release_memory()] is invoked one or
** more times to free up some space before the allocation is performed.
**
** ^The limit is called "soft" because if [sqlite3_release_memory()]
** cannot free sufficient memory to prevent the limit from being exceeded,
** the memory is allocated anyway and the current operation proceeds.
**
** ^A negative or zero value for N means that there is no soft heap limit and
** [sqlite3_release_memory()] will only be called when memory is exhausted.
** ^The default value for the soft heap limit is zero.


**
** ^(SQLite makes a best effort to honor the soft heap limit.
** But if the soft heap limit cannot be honored, execution will
** continue without error or notification.)^  This is why the limit is
** called a "soft" limit.  It is advisory only.
**

** Prior to SQLite version 3.5.0, this routine only constrained the memory
** allocated by a single thread - the same thread in which this routine
** runs.  Beginning with SQLite version 3.5.0, the soft heap limit is
** applied to all threads. The value specified for the soft heap limit
** is an upper bound on the total memory allocation for all threads. In
** version 3.5.0 there is no mechanism for limiting the heap usage for
** individual threads.



















*/











void sqlite3_soft_heap_limit(int);


/*
** CAPI3REF: Extract Metadata About A Column Of A Table
**
** ^This routine returns metadata about a specific column of a specific
** database table accessible using the [database connection] handle
** passed as the first function argument.







|







 







|


|

|



|
>
>
>







 







|
|
|
|
|
|
|
|
|

|
|
|
>
>

<
<
|
<

>
|
|
|
|
|
|
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>

>
>
>
>
>
>
>
>
>
>
>
|
>







1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
....
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
....
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157


4158

4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
** <dd> ^This option takes single argument of type int, interpreted as a 
** boolean, which enables or disables the collection of memory allocation 
** statistics. ^(When memory allocation statistics are disabled, the 
** following SQLite interfaces become non-operational:
**   <ul>
**   <li> [sqlite3_memory_used()]
**   <li> [sqlite3_memory_highwater()]
**   <li> [sqlite3_soft_heap_limit64()]
**   <li> [sqlite3_status()]
**   </ul>)^
** ^Memory allocation statistics are enabled by default unless SQLite is
** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
** allocation statistics are disabled by default.
** </dd>
**
................................................................................
  const char *zPassPhrase        /* Activation phrase */
);
#endif

/*
** CAPI3REF: Suspend Execution For A Short Time
**
** The sqlite3_sleep() function causes the current thread to suspend execution
** for at least a number of milliseconds specified in its parameter.
**
** If the operating system does not support sleep requests with
** millisecond time resolution, then the time will be rounded up to
** the nearest second. The number of milliseconds of sleep actually
** requested from the operating system is returned.
**
** ^SQLite implements this interface by calling the xSleep()
** method of the default [sqlite3_vfs] object.  If the xSleep() method
** of the default VFS is not implemented correctly, or not implemented at
** all, then the behavior of sqlite3_sleep() may deviate from the description
** in the previous paragraphs.
*/
int sqlite3_sleep(int);

/*
** CAPI3REF: Name Of The Folder Holding Temporary Files
**
** ^(If this global variable is made to point to a string which is
................................................................................
** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
*/
int sqlite3_release_memory(int);

/*
** CAPI3REF: Impose A Limit On Heap Size
**
** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
** soft limit on the amount of heap memory that may be allocated by SQLite.
** ^SQLite strives to keep heap memory utilization below the soft heap
** limit by reducing the number of pages held in the page cache
** as heap memory usages approaches the limit.
** ^The soft heap limit is "soft" because even though SQLite strives to stay
** below the limit, it will exceed the limit rather than generate
** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
** is advisory only.
**
** ^The return value from sqlite3_soft_heap_limit64() is the size of
** the soft heap limit prior to the call.  ^If the argument N is negative
** then no change is made to the soft heap limit.  Hence, the current
** size of the soft heap limit can be determined by invoking
** sqlite3_soft_heap_limit64() with a negative argument.
**


** ^If the argument N is zero then the soft heap limit is disabled.

**
** ^(The soft heap limit is not enforced in the current implementation
** if one or more of following conditions are true:
**
** <ul>
** <li> The soft heap limit is set to zero.
** <li> Memory accounting is disabled using a combination of the
**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
** <li> An alternative page cache implementation is specifed using
**      [sqlite3_config]([SQLITE_CONFIG_PCACHE],...).
** <li> The page cache allocates from its own memory pool supplied
**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
**      from the heap.
** </ul>)^
**
** Beginning with SQLite version 3.7.3, the soft heap limit is enforced
** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
** the soft heap limit is enforced on every memory allocation.  Without
** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
** when memory is allocated by the page cache.  Testing suggests that because
** the page cache is the predominate memory user in SQLite, most
** applications will achieve adequate soft heap limit enforcement without
** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
**
** The circumstances under which SQLite will enforce the soft heap limit may
** changes in future releases of SQLite.
*/
sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);

/*
** CAPI3REF: Deprecated Soft Heap Limit Interface
** DEPRECATED
**
** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
** interface.  This routine is provided for historical compatibility
** only.  All new applications should use the
** [sqlite3_soft_heap_limit64()] interface rather than this one.
*/
SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);


/*
** CAPI3REF: Extract Metadata About A Column Of A Table
**
** ^This routine returns metadata about a specific column of a specific
** database table accessible using the [database connection] handle
** passed as the first function argument.

Changes to src/sqliteInt.h.

2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
int sqlite3DbMallocSize(sqlite3*, void*);
void *sqlite3ScratchMalloc(int);
void sqlite3ScratchFree(void*);
void *sqlite3PageMalloc(int);
void sqlite3PageFree(void*);
void sqlite3MemSetDefault(void);
void sqlite3BenignMallocHooks(void (*)(void), void (*)(void));
int sqlite3MemoryAlarm(void (*)(void*, sqlite3_int64, int), void*, sqlite3_int64);
int sqlite3HeapNearlyFull(void);

/*
** On systems with ample stack space and that support alloca(), make
** use of alloca() to obtain space for large automatic objects.  By default,
** obtain space from malloc().
**







<







2526
2527
2528
2529
2530
2531
2532

2533
2534
2535
2536
2537
2538
2539
int sqlite3DbMallocSize(sqlite3*, void*);
void *sqlite3ScratchMalloc(int);
void sqlite3ScratchFree(void*);
void *sqlite3PageMalloc(int);
void sqlite3PageFree(void*);
void sqlite3MemSetDefault(void);
void sqlite3BenignMallocHooks(void (*)(void), void (*)(void));

int sqlite3HeapNearlyFull(void);

/*
** On systems with ample stack space and that support alloca(), make
** use of alloca() to obtain space for large automatic objects.  By default,
** obtain space from malloc().
**

Changes to src/test1.c.

4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405

4406
4407
4408
4409
4410
4411
4412
4413
*/
static int test_soft_heap_limit(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  static int softHeapLimit = 0;
  int amt;
  if( objc!=1 && objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?N?");
    return TCL_ERROR;
  }
  amt = softHeapLimit;
  if( objc==2 ){
    int N;
    if( Tcl_GetIntFromObj(interp, objv[1], &N) ) return TCL_ERROR;
    sqlite3_soft_heap_limit(N);
    softHeapLimit = N;
  }

  Tcl_SetObjResult(interp, Tcl_NewIntObj(amt));
  return TCL_OK;
}

/*
** Usage:   sqlite3_thread_cleanup
**
** Call the sqlite3_thread_cleanup API.







|
|




<

<
|
<
<

>
|







4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398

4399

4400


4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
*/
static int test_soft_heap_limit(
  void * clientData,
  Tcl_Interp *interp,
  int objc,
  Tcl_Obj *CONST objv[]
){
  sqlite3_int64 amt;
  sqlite3_int64 N = -1;
  if( objc!=1 && objc!=2 ){
    Tcl_WrongNumArgs(interp, 1, objv, "?N?");
    return TCL_ERROR;
  }

  if( objc==2 ){

    if( Tcl_GetWideIntFromObj(interp, objv[1], &N) ) return TCL_ERROR;


  }
  amt = sqlite3_soft_heap_limit64(N);
  Tcl_SetObjResult(interp, Tcl_NewWideIntObj(amt));
  return TCL_OK;
}

/*
** Usage:   sqlite3_thread_cleanup
**
** Call the sqlite3_thread_cleanup API.