Documentation Source Text

Check-in [d324d1a30e]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Mention the cell-overwrite optimization on the change log.
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA3-256:d324d1a30ebf3c711a53a8e889346dd04e45713b23c2072aaa3b96fdbfe5fef5
User & Date: drh 2018-05-08 13:35:00
Context
2018-05-08
14:32
More details on the UPSERT documentation. check-in: 7ca811b29f user: drh tags: trunk
13:35
Mention the cell-overwrite optimization on the change log. check-in: d324d1a30e user: drh tags: trunk
2018-05-04
16:43
Documentation for SQLITE_ENABLE_SORTER_REFERENCES. check-in: 183931a121 user: drh tags: trunk
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Changes to pages/changes.in.

36
37
38
39
40
41
42





43
44
45
46
47
48
49
<li> The [CLI] automatically intercepts the raw [EXPLAIN QUERY PLAN] 
     output an reformats it into an ASCII-art graph.
<li> Enhance the query planner to allow the [OR optimization] to proceed
     even if the OR expression has also been converted into an IN
     expression.  Uses of the OR optimization are now also 
     [eqp-or-opt|more clearly shown] in the [EXPLAIN QUERY PLAN] output.
<p><b>Performance:</b>





<li> Queries that use ORDER BY and LIMIT now try to avoid computing
     rows that cannot possibly come in under the LIMIT. This can greatly
     improve performance of ORDER BY LIMIT queries, especially when the
     LIMIT is small relative to the number of unrestricted output rows.
<li> Performance improvements in the LEMON-generated parser.
<p><b>Bug fixes:</b>
<li> For the right-hand table of a LEFT JOIN, compute the values







>
>
>
>
>







36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
<li> The [CLI] automatically intercepts the raw [EXPLAIN QUERY PLAN] 
     output an reformats it into an ASCII-art graph.
<li> Enhance the query planner to allow the [OR optimization] to proceed
     even if the OR expression has also been converted into an IN
     expression.  Uses of the OR optimization are now also 
     [eqp-or-opt|more clearly shown] in the [EXPLAIN QUERY PLAN] output.
<p><b>Performance:</b>
<li> [UPDATE] avoids writing database pages that do not actually change.
     For example, "UPDATE t1 SET x=25 WHERE y=?" becomes a no-op if the
     value in column x is already 25.  Similarly, 
     when doing [UPDATE] on records that span multiple pages, only write
     the subset of pages that contain the changed value(s).
<li> Queries that use ORDER BY and LIMIT now try to avoid computing
     rows that cannot possibly come in under the LIMIT. This can greatly
     improve performance of ORDER BY LIMIT queries, especially when the
     LIMIT is small relative to the number of unrestricted output rows.
<li> Performance improvements in the LEMON-generated parser.
<p><b>Bug fixes:</b>
<li> For the right-hand table of a LEFT JOIN, compute the values