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Overview
| Comment: | Comment fix. No changes to code. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | pcache-bulk-local |
| Files: | files | file ages | folders |
| SHA1: | c1e2ed0ef4d3436d19d3203c5fb553ca |
| User & Date: | drh 2015-07-08 14:13:44 |
Context
|
2015-07-08
| ||
| 16:22 | Enhance the pcache1 page cache so that it tries to allocate a block of SQLITE_DEFAULT_PCACHE_INITSZ pages from malloc() on startup, and uses those preallocated pages when possible rather than going to malloc() for each individual page. About a 5% performance increase for some workloads. check-in: 5348ffc3 user: drh tags: trunk | |
| 14:13 | Comment fix. No changes to code. Closed-Leaf check-in: c1e2ed0e user: drh tags: pcache-bulk-local | |
| 13:40 | Do not do the bulk pcache1 allocations if SQLITE_CONFIG_PAGECACHE specifies a global page cache buffer. check-in: 75d98dae user: drh tags: pcache-bulk-local | |
Changes
Changes to src/pcache1.c.
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** runtime using sqlite3_config(SQLITE_CONFIG_PCACHE_HDRSZ, &size). The ** sizes of the extensions sum to 272 bytes on x64 for 3.8.10, but this ** size can vary according to architecture, compile-time options, and ** SQLite library version number. ** ** If SQLITE_PCACHE_SEPARATE_HEADER is defined, then the extension is obtained ** using a separate memory allocation from the database page content. This ** seeks to overcome the "clownfoot" problem of allocating a few bytes more ** than a power of two with the memory allocator rounding up to the next ** power of two, and leaving the rounded-up space unused. ** ** This module tracks pointers to PgHdr1 objects. Only pcache.c communicates ** with this module. Information is passed back and forth as PgHdr1 pointers. ** ** The pcache.c and pager.c modules deal pointers to PgHdr objects. |
| > |
37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 |
** runtime using sqlite3_config(SQLITE_CONFIG_PCACHE_HDRSZ, &size). The ** sizes of the extensions sum to 272 bytes on x64 for 3.8.10, but this ** size can vary according to architecture, compile-time options, and ** SQLite library version number. ** ** If SQLITE_PCACHE_SEPARATE_HEADER is defined, then the extension is obtained ** using a separate memory allocation from the database page content. This ** seeks to overcome the "clownshoe" problem (also called "internal ** fragmentation" in academic literature) of allocating a few bytes more ** than a power of two with the memory allocator rounding up to the next ** power of two, and leaving the rounded-up space unused. ** ** This module tracks pointers to PgHdr1 objects. Only pcache.c communicates ** with this module. Information is passed back and forth as PgHdr1 pointers. ** ** The pcache.c and pager.c modules deal pointers to PgHdr objects. |