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Overview
| Comment: | Add additional DBSTATUS options for measuring the hit and miss rates against the lookaside memory pool - information useful in tuning the lookaside size. Currently experimental pending analysis of performance impact. |
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| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | experimental |
| Files: | files | file ages | folders |
| SHA1: |
34613f1dc54c638531ca2f5907b71fbe |
| User & Date: | drh 2010-12-20 15:51:59 |
| Original Comment: | Add additional DBSTATUS options for measuring the hit and miss rates against the lookaside memory pool - information useful in tuning the lookaside size. Currently experimental pending analysis of performance impact. |
Context
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2010-12-21
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| 20:36 | Merge into the trunk the experimental enhancements to sqlite3_db_status() for measuring lookaside memory allocator performance. check-in: 8c3b06c2 user: drh tags: trunk | |
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2010-12-20
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| 15:51 | Add additional DBSTATUS options for measuring the hit and miss rates against the lookaside memory pool - information useful in tuning the lookaside size. Currently experimental pending analysis of performance impact. Closed-Leaf check-in: 34613f1d user: drh tags: experimental | |
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2010-12-17
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| 14:03 | Add the "-heap" option to the command-line shell - to allocate a fixed heap for use with SQLITE_ENABLE_MEMSYS5. check-in: 74fff692 user: drh tags: trunk | |
Changes
Changes to src/malloc.c.
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assert( db==0 || db->pnBytesFreed==0 );
#ifndef SQLITE_OMIT_LOOKASIDE
if( db ){
LookasideSlot *pBuf;
if( db->mallocFailed ){
return 0;
}
if( db->lookaside.bEnabled && n<=db->lookaside.sz
&& (pBuf = db->lookaside.pFree)!=0 ){
db->lookaside.pFree = pBuf->pNext;
db->lookaside.nOut++;
if( db->lookaside.nOut>db->lookaside.mxOut ){
db->lookaside.mxOut = db->lookaside.nOut;
}
return (void*)pBuf;
}
}
#else
if( db && db->mallocFailed ){
return 0;
}
#endif
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assert( db==0 || db->pnBytesFreed==0 );
#ifndef SQLITE_OMIT_LOOKASIDE
if( db ){
LookasideSlot *pBuf;
if( db->mallocFailed ){
return 0;
}
if( db->lookaside.bEnabled ){
if( n>db->lookaside.sz ){
db->lookaside.anStat[1]++;
}else if( (pBuf = db->lookaside.pFree)==0 ){
db->lookaside.anStat[2]++;
}else{
db->lookaside.pFree = pBuf->pNext;
db->lookaside.nOut++;
db->lookaside.anStat[0]++;
if( db->lookaside.nOut>db->lookaside.mxOut ){
db->lookaside.mxOut = db->lookaside.nOut;
}
return (void*)pBuf;
}
}
}
#else
if( db && db->mallocFailed ){
return 0;
}
#endif
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Changes to src/sqlite.h.in.
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** The [sqlite3_db_status()] interface will return a non-zero error code ** if a discontinued or unsupported verb is invoked. ** ** <dl> ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> ** <dd>This parameter returns the number of lookaside memory slots currently ** checked out.</dd>)^ ** ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> ** <dd>This parameter returns the approximate number of of bytes of heap ** memory used by all pager caches associated with the database connection.)^ ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. ** ** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> ................................................................................ ** <dd>This parameter returns the approximate number of of bytes of heap ** and lookaside memory used by all prepared statements associated with ** the database connection.)^ ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. ** </dd> ** </dl> */ #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 #define SQLITE_DBSTATUS_CACHE_USED 1 #define SQLITE_DBSTATUS_SCHEMA_USED 2 #define SQLITE_DBSTATUS_STMT_USED 3 #define SQLITE_DBSTATUS_MAX 3 /* Largest defined DBSTATUS */ /* ** CAPI3REF: Prepared Statement Status ** ** ^(Each prepared statement maintains various ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number |
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** The [sqlite3_db_status()] interface will return a non-zero error code ** if a discontinued or unsupported verb is invoked. ** ** <dl> ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> ** <dd>This parameter returns the number of lookaside memory slots currently ** checked out.</dd>)^ ** ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> ** <dd>This parameter returns the number malloc attempts that were ** satisfied using lookaside memory. Only the high-water value is meaningful; ** the current value is always zero. ** checked out.</dd>)^ ** ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> ** <dd>This parameter returns the number malloc attempts that might have ** been satisfied using lookaside memory but failed due to the amount of ** memory requested being larger than the lookaside slot size. ** Only the high-water value is meaningful; ** the current value is always zero. ** checked out.</dd>)^ ** ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> ** <dd>This parameter returns the number malloc attempts that might have ** been satisfied using lookaside memory but failed due to all lookaside ** memory already being in use. ** Only the high-water value is meaningful; ** the current value is always zero. ** checked out.</dd>)^ ** ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> ** <dd>This parameter returns the approximate number of of bytes of heap ** memory used by all pager caches associated with the database connection.)^ ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. ** ** ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> ................................................................................ ** <dd>This parameter returns the approximate number of of bytes of heap ** and lookaside memory used by all prepared statements associated with ** the database connection.)^ ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. ** </dd> ** </dl> */ #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 #define SQLITE_DBSTATUS_CACHE_USED 1 #define SQLITE_DBSTATUS_SCHEMA_USED 2 #define SQLITE_DBSTATUS_STMT_USED 3 #define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 #define SQLITE_DBSTATUS_MAX 6 /* Largest defined DBSTATUS */ /* ** CAPI3REF: Prepared Statement Status ** ** ^(Each prepared statement maintains various ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number |
Changes to src/sqliteInt.h.
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*/
struct Lookaside {
u16 sz; /* Size of each buffer in bytes */
u8 bEnabled; /* False to disable new lookaside allocations */
u8 bMalloced; /* True if pStart obtained from sqlite3_malloc() */
int nOut; /* Number of buffers currently checked out */
int mxOut; /* Highwater mark for nOut */
LookasideSlot *pFree; /* List of available buffers */
void *pStart; /* First byte of available memory space */
void *pEnd; /* First byte past end of available space */
};
struct LookasideSlot {
LookasideSlot *pNext; /* Next buffer in the list of free buffers */
};
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*/
struct Lookaside {
u16 sz; /* Size of each buffer in bytes */
u8 bEnabled; /* False to disable new lookaside allocations */
u8 bMalloced; /* True if pStart obtained from sqlite3_malloc() */
int nOut; /* Number of buffers currently checked out */
int mxOut; /* Highwater mark for nOut */
int anStat[3]; /* 0: hits. 1: size misses. 2: full misses */
LookasideSlot *pFree; /* List of available buffers */
void *pStart; /* First byte of available memory space */
void *pEnd; /* First byte past end of available space */
};
struct LookasideSlot {
LookasideSlot *pNext; /* Next buffer in the list of free buffers */
};
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Changes to src/status.c.
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*pCurrent = db->lookaside.nOut;
*pHighwater = db->lookaside.mxOut;
if( resetFlag ){
db->lookaside.mxOut = db->lookaside.nOut;
}
break;
}
/*
** Return an approximation for the amount of memory currently used
** by all pagers associated with the given database connection. The
** highwater mark is meaningless and is returned as zero.
*/
case SQLITE_DBSTATUS_CACHE_USED: {
|
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*pCurrent = db->lookaside.nOut;
*pHighwater = db->lookaside.mxOut;
if( resetFlag ){
db->lookaside.mxOut = db->lookaside.nOut;
}
break;
}
case SQLITE_DBSTATUS_LOOKASIDE_HIT:
case SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE:
case SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL: {
testcase( op==SQLITE_DBSTATUS_LOOKASIDE_HIT );
testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE );
testcase( op==SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL );
assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)>=0 );
assert( (op-SQLITE_DBSTATUS_LOOKASIDE_HIT)<3 );
*pCurrent = 0;
*pHighwater = db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT];
if( resetFlag ){
db->lookaside.anStat[op - SQLITE_DBSTATUS_LOOKASIDE_HIT] = 0;
}
break;
}
/*
** Return an approximation for the amount of memory currently used
** by all pagers associated with the given database connection. The
** highwater mark is meaningless and is returned as zero.
*/
case SQLITE_DBSTATUS_CACHE_USED: {
|