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71 events for the month beginning 2018-07-01 by user drh

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2018-07-29
18:56
In the command-line shell, always exit if realloc() fails. (check-in: e390023c8e user: drh tags: trunk)
2018-07-28
21:01
Add a small cost penalty to sorting to bias the query planner in favor of plans that do not require a final sorting pass. (check-in: 85b9beb460 user: drh tags: trunk)
16:24
Do not allow a column reference that is converted into a constant by the WHERE-clause constant propagation optimization to be moved to the init-time constant expression list, as the table reference will not work there. This fixes a problem found by OSSFuzz. (check-in: d30b2a9473 user: drh tags: trunk)
14:56
Fix an assert() statement that was made obsolete by the constant propagation enhancement. Problem discovered by OSSFuzz. (check-in: e4b4737e34 user: drh tags: trunk)
14:34
Improved debugging output when the ".selecttrace" option is used in the shell. (check-in: fcb88dd6b0 user: drh tags: trunk)
13:37
An early attempt at refactoring Expr (Closed-Leaf check-in: fc90a53de7 user: drh tags: expr-simplify-branch1)
01:30
Add assert() statements to sqlite3ExprDelete() that prove various symmetry properties of the Expr object that might be exploited to make the Expr object smaller and faster. (check-in: 81f25d5c84 user: drh tags: expr-simplify)
2018-07-27
23:33
Improvements to the parser to increase coverage. Fix the parser so that at least one expresssion is required after PARTITION BY and within the list of expressions on VALUES(). (check-in: 02204f8b24 user: drh tags: trunk)
22:55
When doing a DROP VIEW do not try to delete entries from the sqlite_stat1 table as there are none. (check-in: 7efdba2bbc user: drh tags: trunk)
22:14
Minor grammar changes that help the parser run faster by reducing the number of NUL rule reductions. (check-in: cfd1b00592 user: drh tags: trunk)
20:37
The WHERE-clause constant propagation optimization attempts to use transitive laws to replace column values with constants in the WHERE clause in order to help to query planner make more aggressive optimizations. (check-in: f4229707ac user: drh tags: trunk)
20:01
Reduce the performance cost of the constant propagation optimization to less than 200,000 cycles. (Closed-Leaf check-in: 865249de68 user: drh tags: propagate-const-opt)
18:19
Performance improvement to sqlite3ExprCollSeq(). With this change, the performance of speed-check.sh is within 400,000 cycles of trunk. (check-in: a5f86f49b7 user: drh tags: propagate-const-opt)
18:12
Faster implementation of sqlite3IsBinary(). (check-in: be05d0db09 user: drh tags: propagate-const-opt)
17:51
Only run the constant propagation optimization on joins since that is the only scenario where it is useful. This saves prepare time for the common case of a simple query. (check-in: 598d608359 user: drh tags: propagate-const-opt)
16:57
Constant propagation is now restricted to just the WHERE clause. The mechanism is changed to take affinity and collation into account. This seems to give correct answers. But the search for constant propagation costs 4 million cycles in the speed test. (check-in: 82c67efb72 user: drh tags: propagate-const-opt)
2018-07-26
23:54
Add a test case demonstrating the collation problem with constant propagation. (check-in: 50add839fd user: drh tags: propagate-const-opt)
23:47
Generalize the constant propagation optimization so that it applies on every WHERE close, not just those that contain a subquery. This then demonstrates that the current implementation is inadequate since it does not take into account collating sequences. (check-in: 57eb2abd5b user: drh tags: propagate-const-opt)
21:48
In the unix VFS, give every unixInodeInfo object its own mutex, rather than using the global VFS mutex, to improve concurrency in cases where there are many threads operating on separate database files. (check-in: 22f47cf430 user: drh tags: trunk)
21:16
Initial implementation of the WHERE-clause constant propagation optimization. (check-in: 2fb82ad8eb user: drh tags: propagate-const-opt)
2018-07-24
22:02 Fixed ticket [c694113e50]: Unnecessary ABORT with unhelpful error message plus 5 other changes (artifact: 21658c4e66 user: drh)
22:02
Do not abort running queries due to a CREATE INDEX statement. Allow them to run to completion before being reprepared. Fix for ticket [c694113e50321afdf9]. (check-in: 2bd593332d user: drh tags: trunk)
20:57 New ticket [c694113e50] Unnecessary ABORT with unhelpful error message. (artifact: b1a19bff7c user: drh)
2018-07-23
22:55
Return an SQLITE_NOMEM error if the locking mutex fails to allocate. (Closed-Leaf check-in: 1c94834879 user: drh tags: separate-lock-mutex)
21:10
First attempt at reducing mutex contention in the unix VFS by providing a separate mutex for each unixInodeInfo object. (check-in: f69afaf00a user: drh tags: separate-lock-mutex)
18:32
Attempt to improve the documentation for snapshots. No changes to code. (check-in: 46dd076af5 user: drh tags: trunk)
2018-07-22
00:45
Remove an unused branch in the FK logic. (Closed-Leaf check-in: 523ff77925 user: drh tags: dropViewNoStat)
2018-07-20
19:24
Change the SQLITE_Stat34 bit of the optimization test-control so that it prevents STAT4 data from being used but allows it to be loaded into the Index objects. This permits STAT4 to be turned on and off on a per-statement basis. (check-in: 489f3caf5d user: drh tags: trunk)
18:01
Experimental change to ANALYZE so that when computing values for sqlite_stat1, it uses the maximum number for the number of rows having equivalent values, rather than the average. (Leaf check-in: 085f17e124 user: drh tags: stat1-max)
16:51 Edit [a4663f09c91d1381|a4663f09c9]: Edit check-in comment. (artifact: 132071665c user: drh)
15:44
New checks in PRAGMA integrity_check to validate the autovacuum settings in the header. (check-in: a4663f09c9 user: drh tags: trunk)
13:39
Enhanced detection of problems on the freelist and on overflow list in PRAGMA integrity_check. (check-in: 11e58f5b37 user: drh tags: trunk)
2018-07-19
15:27
Avoid a branch in the commit logic that is unreachable when compiled without SQLITE_ENABLE_BATCH_ATOMIC_WRITE. (check-in: 271b8980c3 user: drh tags: trunk)
14:40
Allow the VACUUM following SQLITE_DBCONFIG_RESET_DATABASE to proceed even if the write-version in the header indicates that the database file is not writable. (check-in: 3dca8b9d5a user: drh tags: trunk)
2018-07-18
19:09
Add the SQLITE_FCNTL_DATA_VERSION file control (check-in: a5087c5c87 user: drh tags: trunk)
17:37
Fix a harmless compiler warning in the pager. Enhance the docs for sqlite3_changes() and sqlite3_total_changes() to refer to the data_version pragma. (check-in: 4c70ea5b0e user: drh tags: trunk)
2018-07-16
11:32
Minor simplification to sqlite3RollbackAll(). (check-in: 432fdc2215 user: drh tags: trunk)
2018-07-11
13:37 Fixed ticket [79cad5e4b2]: UPSERT results in a corrupt database plus 4 other changes (artifact: 2f1cb38602 user: drh)
13:34
On an UPSERT when the order of constraint checks is rearranged, make sure that the affinity transformations on the inserted content occur before any of the constraint checks. Fix for ticket [79cad5e4b2e219dd197242e9e5f4e]. (check-in: d120c45f3d user: drh tags: trunk)
12:50 Ticket [79cad5e4b2] UPSERT results in a corrupt database status still Open with 3 other changes (artifact: 131ac5b232 user: drh) ... 2 similar events omitted.
03:27
Adjustments to VdbeCoverage macros to deal with byte-code branches that can never be taken in some directions. (check-in: b170c0092b user: drh tags: trunk)
2018-07-10
23:31
Remove incorrect ALWAYS() macros from the window function logic. (check-in: 94ac51cc4e user: drh tags: trunk)
22:24
Add VdbeModuleComment()s on the three main code generators for window functions. (check-in: f7c239e959 user: drh tags: trunk)
20:50
Minor comment changes. Add ALWAYS() macros on some unreachable branches in the xStep() methods of built-in window functions. (check-in: f2057542cf user: drh tags: trunk)
19:48
Identify Select objects within a single statement using small sequential integers rather than "0x%p". This is more readable and yields the same result on successive runs. (check-in: a7cdc5bc85 user: drh tags: trunk)
17:10
Further improvements to bytecode branch testing. Fix cases where the macros said a branch could not be taken when in fact it could be. Alter some window function branch coverage macros to indicate that comparison operands cannot be NULL. (check-in: 76e42b7071 user: drh tags: trunk)
16:04
Enhancements and improved documentation to the byte-code branch coverage testing logic. Provide new macros that allow the code to specify that some branch instructions can never take the NULL path and that the OP_Jump opcode is only interested in equal/not-equal. The SQLITE_TESTCTRL_VDBE_COVERAGE file control callback now works slightly differently (it provides the callback with a bitmask of the branch action, rather than an integer). (check-in: cd2da7e1ba user: drh tags: trunk)
07:39
Fix a harmless warning about comment formatting in the previous check-in. Simplify the ORDER BY dereferencing logic so that it avoids unreachable branches. (check-in: 0f6ec605e1 user: drh tags: trunk)
07:25
Assert that if two functions compare equal in every other way, then they must both have OVER clauses, or neither has an OVER clause. Use this fact to simplify expression comparison. (check-in: 52559ad58c user: drh tags: trunk)
06:47
Enhance the sqlite3ExprCompare() routine so that it knows to compare the OVER clause of window functions. (check-in: 0a7649afeb user: drh tags: trunk)
06:32
Enhance the TreeView mechanism so that it shows the window function data structures as part of the abstract syntax tree. (check-in: a2c0e1bec0 user: drh tags: trunk)
05:11
New VDBE comments and coverage macros. (check-in: a9a307265b user: drh tags: trunk)
2018-07-09
22:49
Fixes for various harmless compiler warnings. (check-in: 5023b1b85b user: drh tags: trunk)
20:58
Add a comment to restriction (6) of the push-down optimization. No changes to code. (check-in: 0c8a2f257f user: drh tags: trunk)
20:41
Add an ALWAYS() around a branch in sqlite3BtreeSkipNext() that we believe must always be true. (check-in: 12be361a53 user: drh tags: trunk)
17:33
Remove redundant branches in window function processing. (check-in: 8fdaf3f37e user: drh tags: trunk)
16:24
Simplification to the grammar rules for window functions. Fix a memory leak that can follow an OOM while parsing a comma-separated list of window definitions. (check-in: a568f9c9db user: drh tags: trunk)
02:37
Simplification to the logic that detects misuse of the application-defined function creation interfaces. (check-in: 8f21d77845 user: drh tags: trunk)
02:02
During WITHOUT ROWID table creation, if the sqlite3CreateTable() call fails due to an authorizer denying the INSERT into the sqlite_master table, then detect this fact and abort the CREATE TABLE early, to avoid an assertion fault. (check-in: 164b1641e3 user: drh tags: trunk)
2018-07-08
01:02
Identify specific FuncDef objects for window functions using the pointer to the function name (FuncDef.zName) rather than the pointer to the xStep method. This allows xStep method pointer to be replaced with a single noopStepFunc() procedure, and thus save having lots of different no-op step functions. (check-in: 410e13b0e0 user: drh tags: trunk)
2018-07-07
20:55
Simplifications to the implementation of the sum() SQL function. (check-in: a8b1300237 user: drh tags: trunk)
20:23
Fix the JSON extension so that it can be compiled separately from the amalgamation. (check-in: 4b8cfe7bfe user: drh tags: trunk)
19:47
Add ALWAYS() macros on results of sqlite3_aggregate_context() calls in xInverse() implements, since they can never fail. (check-in: fdef2a921d user: drh tags: trunk)
19:36
Add an assert() to help verify that OP_AggInverse is never called on an accumulator that has not previously been processed by OP_AggStep. (check-in: 4213889103 user: drh tags: trunk)
2018-07-06
17:19
Try to improve the error messages for misformed frame specifications in window definitions. (check-in: 927b95a081 user: drh tags: trunk)
2018-07-05
21:22
Use separate opcodes, OP_AggValue and OP_AggInverse, for the new callbacks associated with Window Functions, for improved readability of EXPLAIN output. (check-in: fa65380509 user: drh tags: trunk)
20:05
Get the json_group_array() and json_group_object() SQL functions working as window functions. (check-in: 916cdc83f5 user: drh tags: trunk)
17:35
Fix the .dump command in the command-line shell so that it does not show extraneous SELECT statements when ".echo on" is enabled. (check-in: 11763cac33 user: drh tags: trunk)
2018-07-01
16:05
Quick patch to the Lemon parser template to avoid an array overread reported by OSSFuzz. A proper fix involves enhancements to the table generators in Lemon to make the overread impossible. That fix will take longer to implement. The current check-in is a stop-gap. (check-in: 3f6730be4c user: drh tags: trunk)
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