Re: [HACKERS] Request improve pg_stat_statements module
On Fri, Feb 28, 2014 at 8:01 AM, Michael Paquier michael.paqu...@gmail.com wrote: Thanks for your patch! On Fri, Feb 28, 2014 at 4:18 PM, pgsql...@postgresql.kr wrote: I patched to add one column in pg_stat_statements module. and sent to author but I need a last time of query, because I want to analyse order by recent time. Hm... I am not sure that this brings much to pg_stat_statements, which is interested to gather normalized information about the queries run on the server. For example, things like calculating the average time of a query by using total_time/calls or even the total time to guess where is an application bottleneck is interesting on a busy system, while the latest timestamp is not really an information that can be used for query tuning. Getting the latest timestamp when a query has run is particularly not interesting on OLTP-like applications where many short transactions are running. It is more interesting to classify query results by either calls, total_time or the combination of both IMO. FWIW, I think it's a neat idea, but I think this proposal is probably too late for 9.4. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Request improve pg_stat_statements module
Thanks for your patch!
On Fri, Feb 28, 2014 at 4:18 PM, pgsql...@postgresql.kr wrote:
I patched to add one column in pg_stat_statements module.
and sent to author but
I need a last time of query, because I want to analyse order by recent time.
Hm... I am not sure that this brings much to pg_stat_statements, which
is interested to gather normalized information about the queries run
on the server. For example, things like calculating the average time
of a query by using total_time/calls or even the total time to guess
where is an application bottleneck is interesting on a busy system,
while the latest timestamp is not really an information that can be
used for query tuning. Getting the latest timestamp when a query has
run is particularly not interesting on OLTP-like applications where
many short transactions are running. It is more interesting to
classify query results by either calls, total_time or the combination
of both IMO.
this patch code below, review please and
I wish to apply at next version.
When submitting patches, there are a couple of things to know, they
are summarized here.
https://wiki.postgresql.org/wiki/Submitting_a_Patch
One of the things that would be interesting for future contributions
in your case is knowing the code convention used in Postgres code (see
comments below for more details):
http://www.postgresql.org/docs/devel/static/source.html
- if (tupdesc-natts == PG_STAT_STATEMENTS_COLS_V1_0)
+ if (tupdesc-natts == PG_STAT_STATEMENTS_COLS_V1_0){
sql_supports_v1_1_counters = false;
+ sql_supports_v1_2_counters = false;
+ }
This is incorrect style, please create a new like for a bracket, like that:
if (cond)
{
blabla;
blabla2;
}
per_query_ctx = rsinfo-econtext-ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
@@ -1185,8 +1195,15 @@
values[i++] = Float8GetDatumFast(tmp.blk_read_time);
values[i++] = Float8GetDatumFast(tmp.blk_write_time);
}
+ // last_executed_timestamp
Please do not use double-slashes for comments, write them instead like that:
/* my comment is here */
Finally be sure to attach a patch to an email and avoid to simply
copy/paste the content of the patch in your email. This is more
user-friendly :) Context diffs are recommended as well.
Regards,
--
Michael
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[HACKERS] Request improve pg_stat_statements module
I patched to add one column in pg_stat_statements module.
and sent to author but
I recived a reject mail because unknown user :(
so I am posting to this mailling.
I need a last time of query, because I want to analyse order by recent time.
this patch code below,
review please and
I wish to apply at next version.
--- diff begin
--- ../pg_stat_statements.orig/pg_stat_statements.c 2014-02-18
04:29:55.0 +0900
+++ pg_stat_statements.c2014-02-28 15:34:38.0 +0900
@@ -59,6 +59,7 @@
#include storage/spin.h
#include tcop/utility.h
#include utils/builtins.h
+#include utils/timestamp.h
PG_MODULE_MAGIC;
@@ -116,6 +117,7 @@
double blk_read_time; /* time spent reading, in msec */
double blk_write_time; /* time spent writing, in msec */
double usage; /* usage factor */
+ TimestampTz last_executed_timestamp; /* last executed
timestamp of query */
} Counters;
/*
@@ -1043,6 +1045,8 @@
e-counters.blk_read_time +=
INSTR_TIME_GET_MILLISEC(bufusage-blk_read_time);
e-counters.blk_write_time +=
INSTR_TIME_GET_MILLISEC(bufusage-blk_write_time);
e-counters.usage += USAGE_EXEC(total_time);
+ /* last executed timestamp */
+ e-counters.last_executed_timestamp = GetCurrentTimestamp();
SpinLockRelease(e-mutex);
}
@@ -1069,7 +1073,8 @@
}
#define PG_STAT_STATEMENTS_COLS_V1_0 14
-#define PG_STAT_STATEMENTS_COLS18
+#define PG_STAT_STATEMENTS_COLS_V1_1 18
+#define PG_STAT_STATEMENTS_COLS19
/*
* Retrieve statement statistics.
@@ -1087,6 +1092,7 @@
HASH_SEQ_STATUS hash_seq;
pgssEntry *entry;
boolsql_supports_v1_1_counters = true;
+ boolsql_supports_v1_2_counters = true;
if (!pgss || !pgss_hash)
ereport(ERROR,
@@ -1107,8 +1113,12 @@
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, return type must be a row type);
- if (tupdesc-natts == PG_STAT_STATEMENTS_COLS_V1_0)
+ if (tupdesc-natts == PG_STAT_STATEMENTS_COLS_V1_0){
sql_supports_v1_1_counters = false;
+ sql_supports_v1_2_counters = false;
+ }
+ if (tupdesc-natts == PG_STAT_STATEMENTS_COLS_V1_1)
+ sql_supports_v1_2_counters = false;
per_query_ctx = rsinfo-econtext-ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
@@ -1185,8 +1195,15 @@
values[i++] = Float8GetDatumFast(tmp.blk_read_time);
values[i++] = Float8GetDatumFast(tmp.blk_write_time);
}
+ // last_executed_timestamp
+ if (sql_supports_v1_2_counters)
+ values[i++] =
TimestampTzGetDatum(tmp.last_executed_timestamp);
+
- Assert(i == (sql_supports_v1_1_counters ?
+ if(sql_supports_v1_2_counters)
+ Assert(i == PG_STAT_STATEMENTS_COLS);
+ else
+ Assert(i == (sql_supports_v1_1_counters ?
PG_STAT_STATEMENTS_COLS :
PG_STAT_STATEMENTS_COLS_V1_0));
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
-- end of diff
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