Many hyperlinks are disabled.
Use anonymous login
to enable hyperlinks.
Overview
| Comment: | Performance optimizations in sqlite3PcacheFetch(). |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
b60cc11ef775c23a2245d9e7a00dab34 |
| User & Date: | drh 2014-02-03 17:04:29 |
Context
|
2014-02-04
| ||
| 15:55 | Rearrange fields in the Parse object for a tighter packing, resulting in an 8% size reduction on x64. (check-in: 3e1a3f68 user: drh tags: trunk) | |
|
2014-02-03
| ||
| 17:04 | Performance optimizations in sqlite3PcacheFetch(). (check-in: b60cc11e user: drh tags: trunk) | |
| 14:04 | Provide hints to the btree layer Next and Previous primitives to let them know if they can be no-ops if the underlying index is unique. (check-in: 6c643e45 user: drh tags: trunk) | |
Changes
Changes to src/pcache.c.
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 .. 86 87 88 89 90 91 92 93 94 95 96 97 98 99 ... 106 107 108 109 110 111 112 113 114 115 116 117 118 119 ... 175 176 177 178 179 180 181 182 183 184 185 186 187 188 ... 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 |
struct PCache {
PgHdr *pDirty, *pDirtyTail; /* List of dirty pages in LRU order */
PgHdr *pSynced; /* Last synced page in dirty page list */
int nRef; /* Number of referenced pages */
int szCache; /* Configured cache size */
int szPage; /* Size of every page in this cache */
int szExtra; /* Size of extra space for each page */
int bPurgeable; /* True if pages are on backing store */
int (*xStress)(void*,PgHdr*); /* Call to try make a page clean */
void *pStress; /* Argument to xStress */
sqlite3_pcache *pCache; /* Pluggable cache module */
PgHdr *pPage1; /* Reference to page 1 */
};
/*
................................................................................
p->pDirtyTail = pPage->pDirtyPrev;
}
if( pPage->pDirtyPrev ){
pPage->pDirtyPrev->pDirtyNext = pPage->pDirtyNext;
}else{
assert( pPage==p->pDirty );
p->pDirty = pPage->pDirtyNext;
}
pPage->pDirtyNext = 0;
pPage->pDirtyPrev = 0;
expensive_assert( pcacheCheckSynced(p) );
}
................................................................................
assert( pPage->pDirtyNext==0 && pPage->pDirtyPrev==0 && p->pDirty!=pPage );
pPage->pDirtyNext = p->pDirty;
if( pPage->pDirtyNext ){
assert( pPage->pDirtyNext->pDirtyPrev==0 );
pPage->pDirtyNext->pDirtyPrev = pPage;
}
p->pDirty = pPage;
if( !p->pDirtyTail ){
p->pDirtyTail = pPage;
}
if( !p->pSynced && 0==(pPage->flags&PGHDR_NEED_SYNC) ){
p->pSynced = pPage;
................................................................................
void *pStress, /* Argument to xStress */
PCache *p /* Preallocated space for the PCache */
){
memset(p, 0, sizeof(PCache));
p->szPage = szPage;
p->szExtra = szExtra;
p->bPurgeable = bPurgeable;
p->xStress = xStress;
p->pStress = pStress;
p->szCache = 100;
}
/*
** Change the page size for PCache object. The caller must ensure that there
................................................................................
*/
int sqlite3PcacheFetch(
PCache *pCache, /* Obtain the page from this cache */
Pgno pgno, /* Page number to obtain */
int createFlag, /* If true, create page if it does not exist already */
PgHdr **ppPage /* Write the page here */
){
sqlite3_pcache_page *pPage = 0;
PgHdr *pPgHdr = 0;
int eCreate;
assert( pCache!=0 );
assert( createFlag==1 || createFlag==0 );
assert( pgno>0 );
/* If the pluggable cache (sqlite3_pcache*) has not been allocated,
** allocate it now.
*/
if( !pCache->pCache && createFlag ){
sqlite3_pcache *p;
p = sqlite3GlobalConfig.pcache2.xCreate(
pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
);
if( !p ){
return SQLITE_NOMEM;
}
sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
pCache->pCache = p;
}
eCreate = createFlag * (1 + (!pCache->bPurgeable || !pCache->pDirty));
if( pCache->pCache ){
pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
}
if( !pPage && eCreate==1 ){
PgHdr *pPg;
/* Find a dirty page to write-out and recycle. First try to find a
** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
** cleared), but if that is not possible settle for any other
** unreferenced dirty page.
|
| > > > > > > > > > | | > > > > | | > > > > > > > | < < |
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 .. 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 ... 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 ... 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 ... 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 |
struct PCache {
PgHdr *pDirty, *pDirtyTail; /* List of dirty pages in LRU order */
PgHdr *pSynced; /* Last synced page in dirty page list */
int nRef; /* Number of referenced pages */
int szCache; /* Configured cache size */
int szPage; /* Size of every page in this cache */
int szExtra; /* Size of extra space for each page */
u8 bPurgeable; /* True if pages are on backing store */
u8 eCreate; /* eCreate value for for xFetch() */
int (*xStress)(void*,PgHdr*); /* Call to try make a page clean */
void *pStress; /* Argument to xStress */
sqlite3_pcache *pCache; /* Pluggable cache module */
PgHdr *pPage1; /* Reference to page 1 */
};
/*
................................................................................
p->pDirtyTail = pPage->pDirtyPrev;
}
if( pPage->pDirtyPrev ){
pPage->pDirtyPrev->pDirtyNext = pPage->pDirtyNext;
}else{
assert( pPage==p->pDirty );
p->pDirty = pPage->pDirtyNext;
if( p->pDirty==0 && p->bPurgeable ){
assert( p->eCreate==1 );
p->eCreate = 2;
}
}
pPage->pDirtyNext = 0;
pPage->pDirtyPrev = 0;
expensive_assert( pcacheCheckSynced(p) );
}
................................................................................
assert( pPage->pDirtyNext==0 && pPage->pDirtyPrev==0 && p->pDirty!=pPage );
pPage->pDirtyNext = p->pDirty;
if( pPage->pDirtyNext ){
assert( pPage->pDirtyNext->pDirtyPrev==0 );
pPage->pDirtyNext->pDirtyPrev = pPage;
}else if( p->bPurgeable ){
assert( p->eCreate==2 );
p->eCreate = 1;
}
p->pDirty = pPage;
if( !p->pDirtyTail ){
p->pDirtyTail = pPage;
}
if( !p->pSynced && 0==(pPage->flags&PGHDR_NEED_SYNC) ){
p->pSynced = pPage;
................................................................................
void *pStress, /* Argument to xStress */
PCache *p /* Preallocated space for the PCache */
){
memset(p, 0, sizeof(PCache));
p->szPage = szPage;
p->szExtra = szExtra;
p->bPurgeable = bPurgeable;
p->eCreate = 2;
p->xStress = xStress;
p->pStress = pStress;
p->szCache = 100;
}
/*
** Change the page size for PCache object. The caller must ensure that there
................................................................................
*/
int sqlite3PcacheFetch(
PCache *pCache, /* Obtain the page from this cache */
Pgno pgno, /* Page number to obtain */
int createFlag, /* If true, create page if it does not exist already */
PgHdr **ppPage /* Write the page here */
){
sqlite3_pcache_page *pPage;
PgHdr *pPgHdr = 0;
int eCreate;
assert( pCache!=0 );
assert( createFlag==1 || createFlag==0 );
assert( pgno>0 );
/* If the pluggable cache (sqlite3_pcache*) has not been allocated,
** allocate it now.
*/
if( !pCache->pCache ){
sqlite3_pcache *p;
if( !createFlag ){
*ppPage = 0;
return SQLITE_OK;
}
p = sqlite3GlobalConfig.pcache2.xCreate(
pCache->szPage, pCache->szExtra + sizeof(PgHdr), pCache->bPurgeable
);
if( !p ){
return SQLITE_NOMEM;
}
sqlite3GlobalConfig.pcache2.xCachesize(p, numberOfCachePages(pCache));
pCache->pCache = p;
}
/* eCreate defines what to do if the page does not exist.
** 0 Do not allocate a new page. (createFlag==0)
** 1 Allocate a new page if doing so is inexpensive.
** (createFlag==1 AND bPurgeable AND pDirty)
** 2 Allocate a new page even it doing so is difficult.
** (createFlag==1 AND !(bPurgeable AND pDirty)
*/
eCreate = createFlag==0 ? 0 : pCache->eCreate;
assert( (createFlag*(1+(!pCache->bPurgeable||!pCache->pDirty)))==eCreate );
pPage = sqlite3GlobalConfig.pcache2.xFetch(pCache->pCache, pgno, eCreate);
if( !pPage && eCreate==1 ){
PgHdr *pPg;
/* Find a dirty page to write-out and recycle. First try to find a
** page that does not require a journal-sync (one with PGHDR_NEED_SYNC
** cleared), but if that is not possible settle for any other
** unreferenced dirty page.
|