Tweak comments in pg_stat_plans_explain().
Fix install bug from commit 261241

the recent change in Makefile was synced with the extension.control
file.

The same commit also breaks debian build, this will be fixed in
another patch
Merge pull request #10 from klando/fix_control

Fix install bug from commit 261241
Tweak comments on where module must be created.
Make available 9.2 track_io_timing stats at the plan granularity.

This commit adds the blk_read_time and blk_write_time columns that are available
with pg_stat_statements on Postgres 9.2. These columns are present no matter
what supported version of Postgres pg_stat_plans is installed on, though on
versions prior to 9.2, they are always NULL. Even on 9.2, they'll generally
always be zero unless track_io_timing is enabled on the server.

This change necessitated bumping PGSP_FILE_HEADER, since the on-disk
representation of plan costs will have changed on some Postgres versions.
Minor tweaks to Makefile comments.
Tweak to setting up PostgreSQL docs.
Clean-up pg_stat_plans_queries documentation.
Tweak the query_valid column to indicate query explainability generally.

The query_valid column has been renamed to query_explainable, and has been
broadened in what it indicates; it now indicates if an entry's query text is
expected to be explainable (or rather, not explainable) for any reason, not just
whether or not the text is currently considered valid.

This has been done for the convenience of third-party analysis tools, that might
otherwise be forced to continually speculatively run pg_stat_plans_explain() on
the same entry. With an application that uses prepared queries selectively, such
as an application with some number of stored functions, the third party analysis
tool could produce an unreasonable level of server log noise. It seems unlikely
that the distinction between query text validity (i.e that a query text is
thought to currently produce the plan for its entry when explained) and general
entry text explainability is a useful enough one to expose to the user.
Fix some regressions in PostgreSQL 9.0.

The standard_conforming_strings = off case was always completely broken, and has
been fixed, while improving the normalize_query() function in a few other minor
ways.

This commit also fixes a compatibility regression with Postgres 9.0, due to the
function str_tolower() having an incompatible interface on that version.

Switched to lower-case SQL within pg_stat_plans.sql. That is the standard for
pg_stat_plans going forward.
Add pg_find_plans submodule.

pg_find_plans is an experimental extension with a dependency on pg_stat_plans,
that facilitates materializing JSON explain texts to a table, and subsequently
querying the texts using SQL, to answer arbitrary questions about their
structure.
Fix pg_find_plans uninstall signatures.
Stamp release 1.0 beta 3.
Tweak join_count function's signature in docs.
Remove superfluous imports.
Standardize headers within SQL files.
Add mention of custom_variable_classes to GUC documentation
Merge pull request #14 from terrorobe/patch-3

Add mention of custom_variable_classes to GUC documentation
Fix broken "Is query text explainable?" logic
Change order of pg_stat_plans columns.

For consistency between the pg_stat_plans view and the pg_stat_plans_explain
function, place planid column first within said view.

PGSP_FILE_HEADER bumped due to change in on-disk representation of entry
statistics.