需要帮助在 12c 中优化 Oracle 查询
Posted
技术标签:
【中文标题】需要帮助在 12c 中优化 Oracle 查询【英文标题】：Need help to optimize Oracle query in 12c 【发布时间】：2016-03-07 20:09:50 【问题描述】：在我们进入 11i 之前，这个特定的查询运行良好，但一旦我们切换到 12c，查询的表现就非常糟糕。 我试图删除提示，它似乎做得更好，但我们的 DBA 希望我们删除所有导致各种子步骤序列化的多个子查询。我不知道如何改变它。 关于我可以做什么或开始做什么的任何指示？
WITH
-- Get all active accounts that have not been suspended and the suspension rules
-- apply for the account
TT1 AS (SELECT
pl.employer_id,
ma.employee_id,
ma.member_account_id,
pl.plan_id
FROM sa_plans pl,
sa_accounts ma
WHERE TRUNC(SYSDATE) BETWEEN pl.start_date AND NVL(pl.end_date, TRUNC(SYSDATE))
AND pl.employer_id = 23
AND pl.plan_type_id NOT IN (4
,1)
AND pl.plan_id = ma.plan_id
AND sa_mc_info.fn_ee_susp_exempt(ma.employee_id, DECODE(pl.plan_type_id, 1, 6 ,5 )) = 0
AND p_outstanding_threshold_perc > 0
AND NVL(ma.auto_suspension_flag, 0) = 0
AND TRUNC(SYSDATE) BETWEEN ma.account_effective_date AND NVL(ma.account_end_date, TRUNC(SYSDATE))
AND ma.account_effective_date != NVL(ma.account_end_date, ma.account_effective_date + 1)
),
-- Get all accounts that were active during the plan year for the current accounts
-- and the outstanding transactions
TT2 AS (SELECT /*+ MATERIALIZE */
ma1.member_account_id,
ma1.plan_id,
ma1.employee_id ,
wwsa.sa_mc_info.fn_acnt_unverified_txns(ma1.member_account_id) outstd_amount
FROM sa_accounts ma1,
TT1 ma
WHERE ma1.account_effective_date != NVL(ma1.account_end_date, ma1.account_effective_date + 1)
AND ma1.plan_id = ma.plan_id
AND ma1.employee_id = ma.employee_id
AND ma1.member_account_id = TT1.member_account_id),
-- Sum the outstanding transactions for the EE and plan
TT3 AS (SELECT /*+ MATERIALIZE ORDERED */
TT1.member_account_id,
SUM(TT2.outstd_amount) outstd_amount
FROM TT1,
TT2
WHERE TT1.employee_id = TT2.employee_id
AND TT1.plan_id = TT2.plan_id
GROUP BY TT1.member_account_id
HAVING SUM(TT2.outstd_amount) > 0),
-- Get the current account balance for accounts with outstanding transactions
TT4 AS (SELECT /*+ MATERIALIZE ORDERED */
TT1.*,
sa_bal_info.fn_account_balance(TT1.member_account_id) balance,
TT3.outstd_amount
FROM TT1,
TT3
WHERE TT1.member_account_id = TT3.member_account_id),
-- Get the list of accounts that need to be suspended
TT5 as (SELECT /*+ MATERIALIZE */
member_account_id,
employee_id
FROM TT4
WHERE outstd_amount > balance * p_outstanding_threshold_perc
AND outstd_amount > NVL(p_minimum_threshold_amount, 0) )
SELECT *
FROM TT5
ORDER BY employee_id;
这是解释计划
-----------------------------------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-----------------------------------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 26 | 8622 (1)| 00:00:01 |
| 1 | TEMP TABLE TRANSFORMATION | | | | | |
| 2 | LOAD AS SELECT | SYS_TEMP_0FD9D666F_DCBC1560 | | | | |
| 3 | NESTED LOOPS | | 4 | 252 | 8600 (1)| 00:00:01 |
| 4 | NESTED LOOPS | | 1707 | 252 | 8600 (1)| 00:00:01 |
|* 5 | TABLE ACCESS BY INDEX ROWID BATCHED| SA_PLANS | 3 | 84 | 8452 (1)| 00:00:01 |
| 6 | INDEX FULL SCAN | SA_PLANS_PK | 19218 | | 75 (2)| 00:00:01 |
|* 7 | INDEX RANGE SCAN | SA_ACCOUNTS_N03 | 569 | | 2 (0)| 00:00:01 |
|* 8 | TABLE ACCESS BY INDEX ROWID | SA_ACCOUNTS | 1 | 35 | 67 (0)| 00:00:01 |
| 9 | LOAD AS SELECT | SYS_TEMP_0FD9D6670_DCBC1560 | | | | |
| 10 | NESTED LOOPS | | 3 | 177 | 8 (0)| 00:00:01 |
| 11 | NESTED LOOPS | | 3 | 177 | 8 (0)| 00:00:01 |
| 12 | VIEW | | 1 | 26 | 2 (0)| 00:00:01 |
| 13 | TABLE ACCESS FULL | SYS_TEMP_0FD9D666F_DCBC1560 | 1 | 22 | 2 (0)| 00:00:01 |
|* 14 | INDEX RANGE SCAN | SA_ACCOUNTS_N01 | 3 | | 2 (0)| 00:00:01 |
|* 15 | TABLE ACCESS BY INDEX ROWID | SA_ACCOUNTS | 3 | 99 | 6 (0)| 00:00:01 |
| 16 | LOAD AS SELECT | SYS_TEMP_0FD9D6671_DCBC1560 | | | | |
|* 17 | FILTER | | | | | |
| 18 | HASH GROUP BY | | 1 | 41 | 5 (20)| 00:00:01 |
|* 19 | HASH JOIN | | 1 | 41 | 4 (0)| 00:00:01 |
| 20 | VIEW | | 1 | 17 | 2 (0)| 00:00:01 |
| 21 | TABLE ACCESS FULL | SYS_TEMP_0FD9D666F_DCBC1560 | 1 | 22 | 2 (0)| 00:00:01 |
| 22 | VIEW | | 1 | 24 | 2 (0)| 00:00:01 |
| 23 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6670_DCBC1560 | 1 | 30 | 2 (0)| 00:00:01 |
| 24 | LOAD AS SELECT | SYS_TEMP_0FD9D6672_DCBC1560 | | | | |
|* 25 | HASH JOIN | | 1 | 78 | 4 (0)| 00:00:01 |
| 26 | VIEW | | 1 | 52 | 2 (0)| 00:00:01 |
| 27 | TABLE ACCESS FULL | SYS_TEMP_0FD9D666F_DCBC1560 | 1 | 22 | 2 (0)| 00:00:01 |
| 28 | VIEW | | 1 | 26 | 2 (0)| 00:00:01 |
| 29 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6671_DCBC1560 | 1 | 19 | 2 (0)| 00:00:01 |
| 30 | LOAD AS SELECT | SYS_TEMP_0FD9D6673_DCBC1560 | | | | |
|* 31 | VIEW | | 1 | 52 | 2 (0)| 00:00:01 |
| 32 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6672_DCBC1560 | 1 | 48 | 2 (0)| 00:00:01 |
| 33 | SORT ORDER BY | | 1 | 26 | 3 (34)| 00:00:01 |
| 34 | VIEW | | 1 | 26 | 2 (0)| 00:00:01 |
| 35 | TABLE ACCESS FULL | SYS_TEMP_0FD9D6673_DCBC1560 | 1 | 12 | 2 (0)| 00:00:01 |
-----------------------------------------------------------------------------------------------------------------------
【问题讨论】：
之前版本的计划是什么（11i 是 Oracle 应用程序的一个版本，我假设您的意图是说它在之前版本的 Oracle 数据库（如 11g）中运行良好）？您发布的查询仍然有一堆提示，但在您的问题文本中说您删除了令人困惑的“提示”。您发布的查询计划是否来自带有所有提示的查询版本？还是去掉了提示的那个？ 缺少“谓词信息” - 它打印在计划表下，您可以用它补充计划吗？ 我会去掉 MATERIALIZE 和 ORDERED 提示（Oracle 将决定他应该使用什么），我会尝试使用 PARALLEL(8) 提示。优化它的“瞄准射击瞄准射击......”，你应该尝试一些方法，因为它取决于很多事情 该函数是 sa_mc_info.fn_ee_susp_exempt() DETERMINISTIC 吗？如果没有，则将其更改为 您在迁移到 12c 后重新创建了优化器统计信息？ 【参考方案1】：尝试执行 TT1 并评估执行时间。如果没问题，那么继续 TT1+TT2 以此类推。在真正解决问题之前，您需要了解问题出在哪里。
【讨论】：
【参考方案2】：我认为您的问题与一个糟糕的计划有关。
所以，正如你所说，它在 11g 数据库上表现得很好，所以你可以做两件事来尝试在短期内解决你的问题：
检查 12c 版本的 optimizer_features_enable 参数。如果设置为 12.* 或更高版本，请尝试将运行查询的会话降级为旧数据库的 11.* 版本。
假设您在生产环境中启用了 Tuning Pack（许可问题 - 注意），您可以使用 SQL Profiles。如何？您可以手动从 11g 复制计划并将其导入 12c 数据库。看看 dbms_sqltune.import_sql_profile。 https://oracle-randolf.blogspot.com.br/2009/03/plan-stability-in-10g-using-existing.html
正如我之前所说，这些都是短期行动。最好评估一下你的 SQL。
【讨论】：
以上是关于需要帮助在 12c 中优化 Oracle 查询的主要内容，如果未能解决你的问题，请参考以下文章
Oracle12c中SQL性能优化（SQL TUNING）新特性之自动重优化（automatic reoptimization）