PIM/MS Windows/SQLite Folder Indices
< PIM | MS Windows
There are issues with locking index files for KMail folders and mmap()/munmap() operations on Windows. Therefore, SQLite-based indices are in development. This page presents detailed development notes for this task.
Started: jstaniek 11:35, 23 April 2008 (CEST)
Introduction
- we call the new implementation SQLite mode for short
- SQLite 3.5.4 is used, as provided by emerge sqlite module; we should not allow using much older versions of sqlite, e.g. 3.1 because of file format differences
- we are using one .index.db file per account, not folder
- kmfolderindex_sqlite.cpp is created and edited as a copy of kmfolderindex.cpp; kmfolderindex.cpp is not compiled in SQLite mode
- kmfolderindex.h is a common header for both kmfolderindex*.cpp implementations
- kmailprivate links to sqlite library, and KMAIL_SQLITE_INDEX is defined to enable #ifdef'd code
KMFolderIndex
- 2008-04-23
- mIndexId unused - removed as well as serialIndexId()
- indexLocation(): added .db suffix to indicate the index is sqlite-based
- INDEX_VERSION is written and checked using 'PRAGMA user_version = <integer>' command [1]
- we do not use temporary filenames, e.g. in writeIndex(): SQLite takes care about safe storage
- updateIndex() no changes, we're changing implementation of KMMsgBase::syncIndexString() and writeIndex() instead
KMMsgBase
- 2008-04-23
- fixed memory leak in KMMsgBase::asIndexString() by adding K_GLOBAL_STATIC for uchar* ret
Status of porting to SQLite
| TOPIC | PORTED | TESTED | NOTES |
|---|---|---|---|
| QString KMFolderIndex::indexLocation() | yes | added .db suffix to indicate the index is sqlite-based | |
| int KMFolderIndex::updateIndex() | yes | no changes | |
| int KMFolderIndex::writeIndex( bool createEmptyIndex ) | |||
| bool KMFolderIndex::readIndex() | |||
| int KMFolderIndex::count(bool cache) | yes | no changes | |
| bool KMFolderIndex::readIndexHeader(int *gv) | |||
| bool KMFolderIndex::updateIndexStreamPtr(bool) | |||
| KMFolderIndex::IndexStatus KMFolderIndex::indexStatus() | |||
| void KMFolderIndex::truncateIndex() | use "DELETE FROM..." | ||
| void KMFolderIndex::fillMessageDict() | yes | no change as it just inserts messages from KMFolderIndex::mMsgList into KMMsgDict | |
| KMMsgInfo* KMFolderIndex::setIndexEntry( int idx, KMMessage *msg ) | yes | no change as it just sets creates a new KMMsgInfo object and inserts it into KMFolderIndex::mMsgList | |
| bool KMFolderIndex::recreateIndex() | yes | no changes as it just calls createIndexFromContents() and readIndex() | |
| off_t KMFolderIndex::mHeaderOffset | replace its public use (e.g. in KMFolderIndex::truncateIndex()) with additional bool indexOpened() | ||
| FILE* KMFolderIndex::mIndexStream, uchar* mIndexStreamPtr, size_t mIndexStreamPtrLength, bool mIndexSwapByteOrder, int mIndexSizeOfLong | these members are unused for SQLite mode because are related to file strorage; moreover byte order and size of long is handled by SQLite in a portable way | ||
| bool KMMsgBase::syncIndexString() const | use 'UPDATE' SQL command to store the message serialized to a BLOB; KMMsgBase::getStringPart() will read it | ||
| QString KMMsgBase::getStringPart(MsgPartType t) const | use 'SELECT' SQL command, harmonize with syncIndexString() implementation |
Open Questions
- should we port .sorted files to sqlite too? (possibly to the same .db file)