OBJS = pg_stat_statements.o
EXTENSION = pg_stat_statements
-DATA = pg_stat_statements--1.1.sql pg_stat_statements--1.0--1.1.sql \
- pg_stat_statements--unpackaged--1.0.sql
+DATA = pg_stat_statements--1.2.sql pg_stat_statements--1.1--1.2.sql \
+ pg_stat_statements--1.0--1.1.sql pg_stat_statements--unpackaged--1.0.sql
ifdef USE_PGXS
PG_CONFIG = pg_config
--- /dev/null
+/* contrib/pg_stat_statements/pg_stat_statements--1.1--1.2.sql */
+
+-- complain if script is sourced in psql, rather than via ALTER EXTENSION
+\echo Use "ALTER EXTENSION pg_stat_statements UPDATE TO '1.2'" to load this file. \quit
+
+/* First we have to remove them from the extension */
+ALTER EXTENSION pg_stat_statements DROP VIEW pg_stat_statements;
+ALTER EXTENSION pg_stat_statements DROP FUNCTION pg_stat_statements();
+
+/* Then we can drop them */
+DROP VIEW pg_stat_statements;
+DROP FUNCTION pg_stat_statements();
+
+/* Now redefine */
+CREATE FUNCTION pg_stat_statements(
+ OUT userid oid,
+ OUT dbid oid,
+ OUT queryid bigint,
+ OUT query text,
+ OUT calls int8,
+ OUT total_time float8,
+ OUT rows int8,
+ OUT shared_blks_hit int8,
+ OUT shared_blks_read int8,
+ OUT shared_blks_dirtied int8,
+ OUT shared_blks_written int8,
+ OUT local_blks_hit int8,
+ OUT local_blks_read int8,
+ OUT local_blks_dirtied int8,
+ OUT local_blks_written int8,
+ OUT temp_blks_read int8,
+ OUT temp_blks_written int8,
+ OUT blk_read_time float8,
+ OUT blk_write_time float8
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME'
+LANGUAGE C;
+
+CREATE VIEW pg_stat_statements AS
+ SELECT * FROM pg_stat_statements();
+
+GRANT SELECT ON pg_stat_statements TO PUBLIC;
-/* contrib/pg_stat_statements/pg_stat_statements--1.1.sql */
-
--- complain if script is sourced in psql, rather than via CREATE EXTENSION
-\echo Use "CREATE EXTENSION pg_stat_statements" to load this file. \quit
-
--- Register functions.
-CREATE FUNCTION pg_stat_statements_reset()
-RETURNS void
-AS 'MODULE_PATHNAME'
-LANGUAGE C;
-
-CREATE FUNCTION pg_stat_statements(
- OUT userid oid,
- OUT dbid oid,
- OUT query text,
- OUT calls int8,
- OUT total_time float8,
- OUT rows int8,
- OUT shared_blks_hit int8,
- OUT shared_blks_read int8,
- OUT shared_blks_dirtied int8,
- OUT shared_blks_written int8,
- OUT local_blks_hit int8,
- OUT local_blks_read int8,
- OUT local_blks_dirtied int8,
- OUT local_blks_written int8,
- OUT temp_blks_read int8,
- OUT temp_blks_written int8,
- OUT blk_read_time float8,
- OUT blk_write_time float8
-)
-RETURNS SETOF record
-AS 'MODULE_PATHNAME'
-LANGUAGE C;
-
--- Register a view on the function for ease of use.
-CREATE VIEW pg_stat_statements AS
- SELECT * FROM pg_stat_statements();
-
-GRANT SELECT ON pg_stat_statements TO PUBLIC;
-
--- Don't want this to be available to non-superusers.
-REVOKE ALL ON FUNCTION pg_stat_statements_reset() FROM PUBLIC;
--- /dev/null
+/* contrib/pg_stat_statements/pg_stat_statements--1.2.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION pg_stat_statements" to load this file. \quit
+
+-- Register functions.
+CREATE FUNCTION pg_stat_statements_reset()
+RETURNS void
+AS 'MODULE_PATHNAME'
+LANGUAGE C;
+
+CREATE FUNCTION pg_stat_statements(
+ OUT userid oid,
+ OUT dbid oid,
+ OUT queryid bigint,
+ OUT query text,
+ OUT calls int8,
+ OUT total_time float8,
+ OUT rows int8,
+ OUT shared_blks_hit int8,
+ OUT shared_blks_read int8,
+ OUT shared_blks_dirtied int8,
+ OUT shared_blks_written int8,
+ OUT local_blks_hit int8,
+ OUT local_blks_read int8,
+ OUT local_blks_dirtied int8,
+ OUT local_blks_written int8,
+ OUT temp_blks_read int8,
+ OUT temp_blks_written int8,
+ OUT blk_read_time float8,
+ OUT blk_write_time float8
+)
+RETURNS SETOF record
+AS 'MODULE_PATHNAME'
+LANGUAGE C;
+
+-- Register a view on the function for ease of use.
+CREATE VIEW pg_stat_statements AS
+ SELECT * FROM pg_stat_statements();
+
+GRANT SELECT ON pg_stat_statements TO PUBLIC;
+
+-- Don't want this to be available to non-superusers.
+REVOKE ALL ON FUNCTION pg_stat_statements_reset() FROM PUBLIC;
#define PGSS_DUMP_FILE "global/pg_stat_statements.stat"
/* This constant defines the magic number in the stats file header */
-static const uint32 PGSS_FILE_HEADER = 0x20120328;
+static const uint32 PGSS_FILE_HEADER = 0x20131115;
+/* PostgreSQL major version number, changes in which invalidate all entries */
+static const uint32 PGSS_PG_MAJOR_VERSION = PG_VERSION_NUM / 100;
/* XXX: Should USAGE_EXEC reflect execution time and/or buffer usage? */
#define USAGE_EXEC(duration) (1.0)
#define JUMBLE_SIZE 1024 /* query serialization buffer size */
+/*
+ * Extension version number, for supporting older extension versions' objects
+ */
+typedef enum pgssVersion
+{
+ PGSS_V1_0 = 0,
+ PGSS_V1_1,
+ PGSS_V1_2
+} pgssVersion;
+
/*
* Hashtable key that defines the identity of a hashtable entry. We separate
* queries by user and by database even if they are otherwise identical.
FILE *file;
uint32 header;
int32 num;
+ int32 pgver;
int32 i;
int query_size;
int buffer_size;
if (fread(&header, sizeof(uint32), 1, file) != 1 ||
header != PGSS_FILE_HEADER ||
+ fread(&pgver, sizeof(uint32), 1, file) != 1 ||
+ pgver != PGSS_PG_MAJOR_VERSION ||
fread(&num, sizeof(int32), 1, file) != 1)
goto error;
if (fwrite(&PGSS_FILE_HEADER, sizeof(uint32), 1, file) != 1)
goto error;
+ if (fwrite(&PGSS_PG_MAJOR_VERSION, sizeof(uint32), 1, file) != 1)
+ goto error;
num_entries = hash_get_num_entries(pgss_hash);
if (fwrite(&num_entries, sizeof(int32), 1, file) != 1)
goto error;
}
#define PG_STAT_STATEMENTS_COLS_V1_0 14
-#define PG_STAT_STATEMENTS_COLS 18
+#define PG_STAT_STATEMENTS_COLS_V1_1 18
+#define PG_STAT_STATEMENTS_COLS 19
/*
* Retrieve statement statistics.
bool is_superuser = superuser();
HASH_SEQ_STATUS hash_seq;
pgssEntry *entry;
- bool sql_supports_v1_1_counters = true;
+ pgssVersion detected_version;
if (!pgss || !pgss_hash)
ereport(ERROR,
/* 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)
- sql_supports_v1_1_counters = false;
+
+ switch (tupdesc->natts)
+ {
+ case PG_STAT_STATEMENTS_COLS_V1_0:
+ detected_version = PGSS_V1_0;
+ break;
+ case PG_STAT_STATEMENTS_COLS_V1_1:
+ detected_version = PGSS_V1_1;
+ break;
+ case PG_STAT_STATEMENTS_COLS:
+ detected_version = PGSS_V1_2;
+ break;
+ default:
+ elog(ERROR, "pgss version unrecognized from tuple descriptor");
+ }
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
{
char *qstr;
+ if (detected_version >= PGSS_V1_2)
+ values[i++] = Int64GetDatumFast((int64) entry->key.queryid);
+
qstr = (char *)
pg_do_encoding_conversion((unsigned char *) entry->query,
entry->query_len,
pfree(qstr);
}
else
+ {
+ if (detected_version >= PGSS_V1_2)
+ nulls[i++] = true;
+
values[i++] = CStringGetTextDatum("<insufficient privilege>");
+ }
/* copy counters to a local variable to keep locking time short */
{
values[i++] = Int64GetDatumFast(tmp.rows);
values[i++] = Int64GetDatumFast(tmp.shared_blks_hit);
values[i++] = Int64GetDatumFast(tmp.shared_blks_read);
- if (sql_supports_v1_1_counters)
+ if (detected_version >= PGSS_V1_1)
values[i++] = Int64GetDatumFast(tmp.shared_blks_dirtied);
values[i++] = Int64GetDatumFast(tmp.shared_blks_written);
values[i++] = Int64GetDatumFast(tmp.local_blks_hit);
values[i++] = Int64GetDatumFast(tmp.local_blks_read);
- if (sql_supports_v1_1_counters)
+ if (detected_version >= PGSS_V1_1)
values[i++] = Int64GetDatumFast(tmp.local_blks_dirtied);
values[i++] = Int64GetDatumFast(tmp.local_blks_written);
values[i++] = Int64GetDatumFast(tmp.temp_blks_read);
values[i++] = Int64GetDatumFast(tmp.temp_blks_written);
- if (sql_supports_v1_1_counters)
+ if (detected_version >= PGSS_V1_1)
{
values[i++] = Float8GetDatumFast(tmp.blk_read_time);
values[i++] = Float8GetDatumFast(tmp.blk_write_time);
}
- Assert(i == (sql_supports_v1_1_counters ?
- PG_STAT_STATEMENTS_COLS : PG_STAT_STATEMENTS_COLS_V1_0));
+ Assert(i == (detected_version == PGSS_V1_0?
+ PG_STAT_STATEMENTS_COLS_V1_0:
+ detected_version == PGSS_V1_1?
+ PG_STAT_STATEMENTS_COLS_V1_1:
+ PG_STAT_STATEMENTS_COLS));
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}
# pg_stat_statements extension
comment = 'track execution statistics of all SQL statements executed'
-default_version = '1.1'
+default_version = '1.2'
module_pathname = '$libdir/pg_stat_statements'
relocatable = true
<title>The <structname>pg_stat_statements</structname> View</title>
<para>
- The statistics gathered by the module are made available via a system view
- named <structname>pg_stat_statements</>. This view contains one row for
- each distinct query, database ID, and user ID (up to the maximum
- number of distinct statements that the module can track). The columns
- of the view are shown in <xref linkend="pgstatstatements-columns">.
+ The statistics gathered by the module are made available via a
+ system view named <structname>pg_stat_statements</>. This view
+ contains one row for each distinct database ID, user ID and query
+ ID (up to the maximum number of distinct statements that the module
+ can track). The columns of the view are shown in
+ <xref linkend="pgstatstatements-columns">.
</para>
<table id="pgstatstatements-columns">
<entry>OID of database in which the statement was executed</entry>
</row>
- <row>
+ <row>
+ <entry><structfield>queryid</structfield></entry>
+ <entry><type>bigint</type></entry>
+ <entry></entry>
+ <entry>Internal hash identifier, computed from the entry's post-parse-analysis tree</entry>
+ </row>
+
+ <row>
<entry><structfield>query</structfield></entry>
<entry><type>text</type></entry>
<entry></entry>
</para>
<para>
- For security reasons, non-superusers are not allowed to see the text of
- queries executed by other users. They can see the statistics, however,
- if the view has been installed in their database.
+ For security reasons, non-superusers are not allowed to see the SQL
+ text or queryid of queries executed by other users. They can see
+ the statistics, however, if the view has been installed in their
+ database.
</para>
<para>
When a constant's value has been ignored for purposes of matching the
query to other queries, the constant is replaced by <literal>?</literal>
in the <structname>pg_stat_statements</> display. The rest of the query
- text is that of the first query that had the particular hash value
- associated with the <structname>pg_stat_statements</> entry.
+ text is that of the first query that had the particular
+ <structfield>queryid</> hash value associated with the
+ <structname>pg_stat_statements</> entry.
</para>
<para>
</para>
<para>
- Since the hash value is computed on the post-parse-analysis representation
- of the queries, the opposite is also possible: queries with identical texts
- might appear as separate entries, if they have different meanings as a
- result of factors such as different <varname>search_path</> settings.
+ Since the <structfield>queryid</> hash value is computed on the
+ post-parse-analysis representation of the queries, the opposite is
+ also possible: queries with identical texts might appear as
+ separate entries, if they have different meanings as a result of
+ factors such as different <varname>search_path</> settings.
+ </para>
+
+ <para>
+ Consumers of <literal>pg_stat_statements</> may wish to use
+ <structfield>queryid</> (perhaps in composite with
+ <structfield>dbid</> and <structfield>userid</>) as a more stable
+ and reliable identifier for each entry than its query text.
+ However, it is important to understand that there are only limited
+ guarantees around the stability of the <structfield>queryid</> hash
+ value. Since the identifier is derived from the
+ post-parse-analysis tree, its value is a function of, among other
+ things, the internal identifiers that comprise this representation.
+ This has some counterintuitive implications. For example, a query
+ against a table that is fingerprinted by
+ <literal>pg_stat_statements</> will appear distinct to a
+ subsequently executed query that a reasonable observer might judge
+ to be a non-distinct, if in the interim the table was dropped and
+ re-created. The hashing process is sensitive to difference in
+ machine architecture and other facets of the platform.
+ Furthermore, it is not safe to assume that <structfield>queryid</>
+ will be stable across major versions of <productname>PostgreSQL</>.
+ </para>
+
+ <para>
+ As a rule of thumb, an assumption of the stability or comparability
+ of <structfield>querid</> values should be predicated on the the
+ underlying catalog metadata and hash function implementation
+ details exactly matching. Any two servers participating in any
+ variety of replication based on physical WAL-replay can be expected
+ to have identical <structfield>querid</> values for the same query.
+ Logical replication schemes do not have replicas comparable in all
+ relevant regards, and so <structfield>querid</> will not be a
+ useful identifier for accumulating costs for the entire replica
+ set. If in doubt, direct testing is recommended.
</para>
</sect2>
projects / postgresql / commitdiff