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| author | dan <dan@noemail.net> | 2016-05-04 11:28:03 +0000 |
|---|---|---|
| committer | dan <dan@noemail.net> | 2016-05-04 11:28:03 +0000 |
| commit | c88ae52d868d8da91931ef3863e96ca661b4356d (patch) | |
| tree | 430e14234af4fd6e4ae8f4816c56803c740b4f6a /src | |
| parent | 12b35ea980c777c5c76f7e528567d799f8eade9c (diff) | |
| download | sqlite-c88ae52d868d8da91931ef3863e96ca661b4356d.tar.gz sqlite-c88ae52d868d8da91931ef3863e96ca661b4356d.zip | |
Disable the PagerDontWrite() optimization for temp tables. It can cause database corruption if a page passed to PagerDontWrite() is dirty at the start of a transaction that is subsequently rolled back.
FossilOrigin-Name: 6341ab2ffef298ca16b323358afbea4a4c1fb0e1
Diffstat (limited to 'src')
| -rw-r--r-- | src/pager.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/src/pager.c b/src/pager.c index d24337cd5..8ef0492e5 100644 --- a/src/pager.c +++ b/src/pager.c @@ -6008,10 +6008,16 @@ int sqlite3PagerIswriteable(DbPage *pPg){ ** ** Tests show that this optimization can quadruple the speed of large ** DELETE operations. +** +** This optimization cannot be used with a temp-file, as the page may +** have been dirty at the start of the transaction. In that case, if +** memory pressure forces page pPg out of the cache, the data does need +** to be written out to disk so that it may be read back in if the +** current transaction is rolled back. */ void sqlite3PagerDontWrite(PgHdr *pPg){ Pager *pPager = pPg->pPager; - if( (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){ + if( !pPager->tempFile && (pPg->flags&PGHDR_DIRTY) && pPager->nSavepoint==0 ){ PAGERTRACE(("DONT_WRITE page %d of %d\n", pPg->pgno, PAGERID(pPager))); IOTRACE(("CLEAN %p %d\n", pPager, pPg->pgno)) pPg->flags |= PGHDR_DONT_WRITE; |