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Overview
Comment: | Improvements to the SQLITE_CONFIG_PAGECACHE documentation. Enhance the command-line shell to be able to take advantage of the full range of SQLITE_CONFIG_PAGECACHE capabilities, such as setting pMem==NULL and N<0. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
2518d5c971c4b32d9227b3bb7259162e |
User & Date: | drh 2015-11-11 15:28:52.898 |
Context
2015-11-12
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14:57 | First attempt at enhancing the "PRAGMA cache_spill" statement to accept a cache threashold size. (check-in: 549d42be0d user: drh tags: cache_spill=N) | |
2015-11-11
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18:43 | Fix missing word in a documentation comment. No changes to code. (check-in: ed24d30265 user: mistachkin tags: trunk) | |
18:08 | Add a hack to debug out a description of the WHERE clause of a SELECT (or other) statement. Use this in script tool/schemalint.tcl to automatically recommend indexes that might speed up specific queries. (check-in: c6fa01c28e user: dan tags: schemalint) | |
15:28 | Improvements to the SQLITE_CONFIG_PAGECACHE documentation. Enhance the command-line shell to be able to take advantage of the full range of SQLITE_CONFIG_PAGECACHE capabilities, such as setting pMem==NULL and N<0. (check-in: 2518d5c971 user: drh tags: trunk) | |
2015-11-10
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14:51 | Improved output formatting for "PRAGMA parser_trace=ON;". (check-in: e43e1171fd user: drh tags: trunk) | |
Changes
Changes to src/shell.c.
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4597 4598 4599 4600 4601 4602 4603 | if( n<1 ) n = 1; sqlite3_config(SQLITE_CONFIG_SCRATCH, malloc(n*sz+1), sz, n); data.shellFlgs |= SHFLG_Scratch; }else if( strcmp(z,"-pagecache")==0 ){ int n, sz; sz = (int)integerValue(cmdline_option_value(argc,argv,++i)); if( sz>70000 ) sz = 70000; | | < | > | 4597 4598 4599 4600 4601 4602 4603 4604 4605 4606 4607 4608 4609 4610 4611 4612 4613 4614 | if( n<1 ) n = 1; sqlite3_config(SQLITE_CONFIG_SCRATCH, malloc(n*sz+1), sz, n); data.shellFlgs |= SHFLG_Scratch; }else if( strcmp(z,"-pagecache")==0 ){ int n, sz; sz = (int)integerValue(cmdline_option_value(argc,argv,++i)); if( sz>70000 ) sz = 70000; if( sz<0 ) sz = 0; n = (int)integerValue(cmdline_option_value(argc,argv,++i)); sqlite3_config(SQLITE_CONFIG_PAGECACHE, (n>0 && sz>0) ? malloc(n*sz) : 0, sz, n); data.shellFlgs |= SHFLG_Pagecache; }else if( strcmp(z,"-lookaside")==0 ){ int n, sz; sz = (int)integerValue(cmdline_option_value(argc,argv,++i)); if( sz<0 ) sz = 0; n = (int)integerValue(cmdline_option_value(argc,argv,++i)); if( n<0 ) n = 0; |
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Changes to src/sqlite.h.in.
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1595 1596 1597 1598 1599 1600 1601 | ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large ** [sqlite3_malloc|heap allocations]. ** This can help [Robson proof|prevent memory allocation failures] due to heap ** fragmentation in low-memory embedded systems. ** </dd> ** ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> | | | | < | | | < | > | | > > > | > | > | | | > | 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 | ** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large ** [sqlite3_malloc|heap allocations]. ** This can help [Robson proof|prevent memory allocation failures] due to heap ** fragmentation in low-memory embedded systems. ** </dd> ** ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> ** <dd> ^The SQLITE_CONFIG_PAGECACHE option a memory pool ** that SQLite can use for the database page cache with the default page ** cache implementation. ** This configuration option is a no-op if an application-define page ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to ** 8-byte aligned memory (pMem), the size of each page cache line (sz), ** and the number of cache lines (N). ** The sz argument should be the size of the largest database page ** (a power of two between 512 and 65536) plus some extra bytes for each ** page header. ^The number of extra bytes needed by the page header ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. ** ^It is harmless, apart from the wasted memory, ** for the sz parameter to be larger than necessary. The pMem ** argument must be either a NULL pointer or a pointer to an 8-byte ** aligned block of memory of at least sz*N bytes, otherwise ** subsequent behavior is undefined. ** ^When pMem is not NULL, SQLite will strive to use the memory provided ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if ** a page cache line is larger than sz bytes or if all of the pMem buffer ** is exhausted. ** ^If pMem is NULL and N is non-zero, then each database connection ** does an initial bulk allocation for page cache memory ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or ** of -1024*N bytes if N is negative, . ^If additional ** page cache memory is needed beyond what is provided by the initial ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each ** additional cache line. </dd> ** ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer ** that SQLite will use for all of its dynamic memory allocation needs ** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and ** [SQLITE_CONFIG_PAGECACHE]. ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled |
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