aurora_stat_dml_activity
报告 Aurora PostgreSQL 集群中数据库上每种类型的数据操作语言（DML）操作的累积活动。
语法
aurora_stat_dml_activity(database_oid)Arguments
- database_oid
-
Aurora PostgreSQL 集群中数据库的对象 ID（OID）。
返回类型
SETOF 记录
使用说明
aurora_stat_dml_activity 函数仅适用于 Aurora PostgreSQL 版本 3.1，与 PostgreSQL 引擎 11.6 及更高版本兼容。
在具有大量数据库的 Aurora PostgreSQL 集群上使用此函数，以确定哪些数据库具有更多或更慢的 DML 活动，或两者兼有。
aurora_stat_dml_activity 函数返回运行操作的次数以及选择、插入、更新和删除操作的累积延迟（以微秒为单位）。该报告仅包括成功的 DML 操作。
您可以使用 PostgreSQL 统计信息访问函数 pg_stat_reset 重置此统计信息。您可以使用 pg_stat_get_db_stat_reset_time 函数检查上次重置此统计信息的时间。有关 PostgreSQL 统计访问函数的更多信息，请参阅 PostgreSQL 文档中的统计收集器
示例
以下示例说明如何报告连接的数据库的 DML 活动统计数据库。
––Define the oid variable from connected database by using \gset=>SELECT oid, datname FROM pg_database WHERE datname=(select current_database()) \gset=>SELECT * FROM aurora_stat_dml_activity(:oid);select_count | select_latency_microsecs | insert_count | insert_latency_microsecs | update_count | update_latency_microsecs | delete_count | delete_latency_microsecs --------------+--------------------------+--------------+--------------------------+--------------+--------------------------+--------------+-------------------------- 178957 | 66684115 | 171065 | 28876649 | 519538 | 1454579206167 | 1 | 53027–– Showing the same results with expanded display on=>SELECT * FROM aurora_stat_dml_activity(:oid);-[ RECORD 1 ]------------+-------------- select_count | 178957 select_latency_microsecs | 66684115 insert_count | 171065 insert_latency_microsecs | 28876649 update_count | 519538 update_latency_microsecs | 1454579206167 delete_count | 1 delete_latency_microsecs | 53027
以下示例显示了 Aurora PostgreSQL 集群中所有数据库的 DML 活动统计信息。该集群有两个数据库 postgres 和 mydb。逗号分隔的列表对应 select_count、select_latency_microsecs、insert_count、insert_latency_microsecs、update_count、update_latency_microsecs、delete_count 和 delete_latency_microsecs 字段。
Aurora PostgreSQL 创建并使用名为 rdsadmin 的系统数据库来支持管理操作，例如备份、还原、运行状况检查、复制等。这些 DML 操作对您的 Aurora PostgreSQL 集群没有任何影响。
=>SELECT oid, datname, aurora_stat_dml_activity(oid) FROM pg_database;oid | datname | aurora_stat_dml_activity -------+----------------+----------------------------------------------------------------- 14006 | template0 | (,,,,,,,) 16384 | rdsadmin | (2346623,1211703821,4297518,817184554,0,0,0,0) 1 | template1 | (,,,,,,,) 14007 | postgres | (178961,66716329,171065,28876649,519538,1454579206167,1,53027) 16401 | mydb | (200246,64302436,200036,107101855,600000,83659417514,0,0)
以下示例显示了所有数据库的 DML 活动统计信息，这些统计信息按列进行组织，以提高可读性。
SELECT db.datname, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 1), '()') AS select_count, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 2), '()') AS select_latency_microsecs, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 3), '()') AS insert_count, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 4), '()') AS insert_latency_microsecs, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 5), '()') AS update_count, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 6), '()') AS update_latency_microsecs, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 7), '()') AS delete_count, BTRIM(SPLIT_PART(db.asdmla::TEXT, ',', 8), '()') AS delete_latency_microsecs FROM (SELECT datname, aurora_stat_dml_activity(oid) AS asdmla FROM pg_database ) AS db;datname | select_count | select_latency_microsecs | insert_count | insert_latency_microsecs | update_count | update_latency_microsecs | delete_count | delete_latency_microsecs ----------------+--------------+--------------------------+--------------+--------------------------+--------------+--------------------------+--------------+-------------------------- template0 | | | | | | | | rdsadmin | 4206523 | 2478812333 | 7009414 | 1338482258 | 0 | 0 | 0 | 0 template1 | | | | | | | | fault_test | 66 | 452099 | 0 | 0 | 0 | 0 | 0 | 0 db_access_test | 1 | 5982 | 0 | 0 | 0 | 0 | 0 | 0 postgres | 42035 | 95179203 | 5752 | 2678832898 | 21157 | 441883182488 | 2 | 1520 mydb | 71 | 453514 | 0 | 0 | 1 | 190 | 1 | 152
以下示例显示具有 OID 16401 的数据库每个 DML 操作的平均累积延迟时间（累积延迟除以计数）。
=>SELECT select_count, select_latency_microsecs, select_latency_microsecs/NULLIF(select_count,0) select_latency_per_exec, insert_count, insert_latency_microsecs, insert_latency_microsecs/NULLIF(insert_count,0) insert_latency_per_exec, update_count, update_latency_microsecs, update_latency_microsecs/NULLIF(update_count,0) update_latency_per_exec, delete_count, delete_latency_microsecs, delete_latency_microsecs/NULLIF(delete_count,0) delete_latency_per_exec FROM aurora_stat_dml_activity(16401);-[ RECORD 1 ]------------+------------- select_count | 451312 select_latency_microsecs | 80205857 select_latency_per_exec | 177 insert_count | 451001 insert_latency_microsecs | 123667646 insert_latency_per_exec | 274 update_count | 1353067 update_latency_microsecs | 200900695615 update_latency_per_exec | 148478 delete_count | 12 delete_latency_microsecs | 448 delete_latency_per_exec | 37