# aurora\$1stat\$1dml\$1activity
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)
```
## 参数
*database\$1oid*
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](https://www.postgresql.org/docs/9.1/monitoring-stats.html)。
## 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
```