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Typo in perform.sgml? 7+ messages / 3 participants [nested] [flat]
* Typo in perform.sgml? @ 2019-12-07 11:05 Tatsuo Ishii <[email protected]> 0 siblings, 1 reply; 7+ messages in thread From: Tatsuo Ishii @ 2019-12-07 11:05 UTC (permalink / raw) To: [email protected] Around line 904 of perform.sgml "These node types have the ability to discard subnodes which they are able to determine won't contain any records required by the query." I was not able to parse this. Maybe "that they " is needed after "determine"? Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp ^ permalink raw reply [nested|flat] 7+ messages in thread
* Re: Typo in perform.sgml? @ 2019-12-07 13:01 Julien Rouhaud <[email protected]> parent: Tatsuo Ishii <[email protected]> 0 siblings, 1 reply; 7+ messages in thread From: Julien Rouhaud @ 2019-12-07 13:01 UTC (permalink / raw) To: Tatsuo Ishii <[email protected]>; +Cc: [email protected] On Sat, Dec 7, 2019 at 12:05 PM Tatsuo Ishii <[email protected]> wrote: > > Around line 904 of perform.sgml > > "These node types have the ability to discard subnodes which they are > able to determine won't contain any records required by the query." > > I was not able to parse this. Maybe "that they " is needed after > "determine"? Agreed. Also, I'm not a native english speaker either, but the "which" sounds weird too. How about: These node types have the ability to discard subnodes for which they are able to determine that won't contain any records required by the query. ^ permalink raw reply [nested|flat] 7+ messages in thread
* Re: Typo in perform.sgml? @ 2019-12-07 16:46 Tom Lane <[email protected]> parent: Julien Rouhaud <[email protected]> 0 siblings, 1 reply; 7+ messages in thread From: Tom Lane @ 2019-12-07 16:46 UTC (permalink / raw) To: Julien Rouhaud <[email protected]>; +Cc: Tatsuo Ishii <[email protected]>; [email protected] Julien Rouhaud <[email protected]> writes: > On Sat, Dec 7, 2019 at 12:05 PM Tatsuo Ishii <[email protected]> wrote: >> Around line 904 of perform.sgml >> "These node types have the ability to discard subnodes which they are >> able to determine won't contain any records required by the query." >> >> I was not able to parse this. Maybe "that they " is needed after >> "determine"? > Agreed. Also, I'm not a native english speaker either, but the > "which" sounds weird too. How about: > These node types have the ability to discard subnodes for which they > are able to determine that won't contain any records required by the > query. Hm. A grammar purist would say that the "which" should be "that", because it's introducing a restrictive clause. But I think the real problem here is that "contain" is a crummy choice of verb: the notion of a plan node "containing" records is what seems weird to me. I think "produce" might work better. Also, there's a lot of unnecessary words here; I think we should be trying to make the sentence shorter not longer. How about something like "These node types will discard subnodes when they detect that a particular subnode won't produce any records required by the query." Actually, that whole para could do with a rewrite; whoever wrote it was obviously not familiar with Strunk & White's dictum "Omit needless words". regards, tom lane ^ permalink raw reply [nested|flat] 7+ messages in thread
* Re: Typo in perform.sgml? @ 2019-12-07 20:56 Tom Lane <[email protected]> parent: Tom Lane <[email protected]> 0 siblings, 1 reply; 7+ messages in thread From: Tom Lane @ 2019-12-07 20:56 UTC (permalink / raw) To: Julien Rouhaud <[email protected]>; +Cc: Tatsuo Ishii <[email protected]>; [email protected] I wrote: > Actually, that whole para could do with a rewrite; whoever wrote > it was obviously not familiar with Strunk & White's dictum > "Omit needless words". Looking closer, there were also some unnecessary inconsistencies with the rest of the section, such as use of "records" rather than "rows", and different markup choices. I propose the attached ... it's actually a bit longer than the original, but that's because it offers more details. regards, tom lane Attachments: [text/x-diff] improve-subplan-pruning-docs.patch (1.6K, 2-improve-subplan-pruning-docs.patch) download | inline diff: diff --git a/doc/src/sgml/perform.sgml b/doc/src/sgml/perform.sgml index 715aff6..0f61b09 100644 --- a/doc/src/sgml/perform.sgml +++ b/doc/src/sgml/perform.sgml @@ -896,15 +896,16 @@ EXPLAIN ANALYZE SELECT * FROM tenk1 WHERE unique1 < 100 AND unique2 > 9000 </para> <para> - Generally, the <command>EXPLAIN</command> output will display details for - every plan node which was generated by the query planner. However, there - are cases where the executor is able to determine that certain nodes are - not required; currently, the only node types to support this are the - <literal>Append</literal> and <literal>MergeAppend</literal> nodes. These - node types have the ability to discard subnodes which they are able to - determine won't contain any records required by the query. It is possible - to determine that nodes have been removed in this way by the presence of a - "Subplans Removed" property in the <command>EXPLAIN</command> output. + Normally, <command>EXPLAIN</command> will display every plan node + created by the planner. However, there are cases where the executor + can determine that certain nodes need not be executed because they + cannot produce any rows, based on parameter values that were not + available at planning time. (Currently this can only happen for child + nodes of an Append or MergeAppend node that is scanning a partitioned + table.) When this happens, those plan nodes are omitted from + the <command>EXPLAIN</command> output and a <literal>Subplans + Removed: <replaceable>N</replaceable></literal> annotation appears + instead. </para> </sect2> ^ permalink raw reply [nested|flat] 7+ messages in thread
* Re: Typo in perform.sgml? @ 2019-12-08 02:51 Tatsuo Ishii <[email protected]> parent: Tom Lane <[email protected]> 0 siblings, 1 reply; 7+ messages in thread From: Tatsuo Ishii @ 2019-12-08 02:51 UTC (permalink / raw) To: [email protected]; +Cc: [email protected]; [email protected] > I wrote: >> Actually, that whole para could do with a rewrite; whoever wrote >> it was obviously not familiar with Strunk & White's dictum >> "Omit needless words". > > Looking closer, there were also some unnecessary inconsistencies with > the rest of the section, such as use of "records" rather than "rows", > and different markup choices. I propose the attached ... it's > actually a bit longer than the original, but that's because it > offers more details. Thanks for looking into this. The patch looks much cleaner than before. Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp ^ permalink raw reply [nested|flat] 7+ messages in thread
* Re: Typo in perform.sgml? @ 2019-12-08 08:07 Julien Rouhaud <[email protected]> parent: Tatsuo Ishii <[email protected]> 0 siblings, 1 reply; 7+ messages in thread From: Julien Rouhaud @ 2019-12-08 08:07 UTC (permalink / raw) To: Tatsuo Ishii <[email protected]>; +Cc: Tom Lane <[email protected]>; [email protected] On Sun, Dec 8, 2019 at 3:51 AM Tatsuo Ishii <[email protected]> wrote: > > > I wrote: > >> Actually, that whole para could do with a rewrite; whoever wrote > >> it was obviously not familiar with Strunk & White's dictum > >> "Omit needless words". > > > > Looking closer, there were also some unnecessary inconsistencies with > > the rest of the section, such as use of "records" rather than "rows", > > and different markup choices. I propose the attached ... it's > > actually a bit longer than the original, but that's because it > > offers more details. > > Thanks for looking into this. The patch looks much cleaner than > before. I agree this is way better! ^ permalink raw reply [nested|flat] 7+ messages in thread
* Re: Typo in perform.sgml? @ 2019-12-08 15:37 Tom Lane <[email protected]> parent: Julien Rouhaud <[email protected]> 0 siblings, 0 replies; 7+ messages in thread From: Tom Lane @ 2019-12-08 15:37 UTC (permalink / raw) To: Julien Rouhaud <[email protected]>; +Cc: Tatsuo Ishii <[email protected]>; [email protected] Julien Rouhaud <[email protected]> writes: > On Sun, Dec 8, 2019 at 3:51 AM Tatsuo Ishii <[email protected]> wrote: >> Thanks for looking into this. The patch looks much cleaner than >> before. > I agree this is way better! Pushed like that, then. regards, tom lane ^ permalink raw reply [nested|flat] 7+ messages in thread
end of thread, other threads:[~2019-12-08 15:37 UTC | newest] Thread overview: 7+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2019-12-07 11:05 Typo in perform.sgml? Tatsuo Ishii <[email protected]> 2019-12-07 13:01 ` Julien Rouhaud <[email protected]> 2019-12-07 16:46 ` Tom Lane <[email protected]> 2019-12-07 20:56 ` Tom Lane <[email protected]> 2019-12-08 02:51 ` Tatsuo Ishii <[email protected]> 2019-12-08 08:07 ` Julien Rouhaud <[email protected]> 2019-12-08 15:37 ` Tom Lane <[email protected]>
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