Here is an updated patch per discussion.
* Counters are accumulative. They contain I/Os by child nodes.
* Text format shows all counters.
* Add "shared_" prefix to variables representing shared buffers/blocks.
Euler Taveira de Oliveira <euler@timbira.com> wrote:
> Itagaki Takahiro escreveu:
> > I think the current output is enough and useful in normal use.
> > We can use XML or JSON format for more details.
> >
> I don't think it is a good idea to have different information in different
> formats. I'm with Robert; *don't* do that.
I'm afraid of the human-unreadability of the text format, that is discussed
in the YAML format thread. ...but I found we say the following in the docs.
XML or JSON output contains the same information as the text output format
http://developer.postgresql.org/pgdocs/postgres/sql-explain.html
Obviously I should not hide any information only in the text format.
The new output will be: (in one line)
Shared Blocks: (hit=2 read=1641 written=0) Local Blocks: (hit=0 read=0 written=0) Temp Blocks: (read=1443
written=1443)
> There are nodes that don't read or write blocks.
This will be impossible now because we re-defined the meaning of counters
as "accumulated number of I/O". Even if the node never read or write blocks,
it might contain some child nodes with I/O.
Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center
