Not the answer you're looking for? Can the use of flaps reduce the steady-state turn radius at a given airspeed and angle of bank? warehouses where the overhead of the As this is an undocumented hint, it should not be used by developers! Tom, suppose I did a distinct on the some of the columns of a multi column primary key. long-running query. just guess, but look like your statement not using index on archive_date column Oracle has to fulfill a full table scan for the second (inner) query, build the results and then compare them to the first (outer) query, that's why it's slowing down. The best answers are voted up and rise to the top, Not the answer you're looking for? Can I also say: 'ich tut mir leid' instead of 'es tut mir leid'? I made the same mistake :-) Each order has mutliple tasks, and if one of those tasks has an engineer assigned, the order counts as "allocated". Alternatively is there a simpler/different/better SQL statement I should use? "EUSR_CONN_SETUP_F_CNT" AS "EUSRCONNSETUPFCNT", D1. This approach also forces you to modify the business logic to keep the flag updated, but the queries will be lightning fast. We guess, nothing like this is mentioned in the documentation. Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the community. Group by is a great tool. I tried this but it was still running over a minute later when I cancelled it. I thought of that, too, but I think this query is not the fastest, too. If you don't want/need to group by by the other columns, you should not have them there. Last updated: March 30, 2018 - 4:37 am UTC, NARENDRA GUPTA, February 15, 2018 - 8:52 am UTC, Martin Rose, March 27, 2018 - 3:25 pm UTC, Martin Rose, March 28, 2018 - 3:13 pm UTC, Martin Rose, March 28, 2018 - 3:39 pm UTC, Martin Rose, March 29, 2018 - 3:31 pm UTC. Making statements based on opinion; back them up with references or personal experience. when we run it in sqlplus they are almost the same (about 20 seconds more for distinct). 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The way I solved this was to do a COUNT(*) of all rows on both sides but GROUP them on CREATETIME formatted as a BIGINT, such as 'YYYYHHMMHR24'. The question title is not very helpful. This doesn't work because it should only return orders where, It think it returns the same result as the query that you specified: SELECT orderID FROM tasks WHERE orderID NOT IN (SELECT DISTINCT orderID FROM tasks WHERE engineer1 IS NOT NULL AND engineer2 IS NOT NULL) which I believe returns:All orders that do not have any tasks with both engineers assigned. I have following alternative using PL/SQL function, but still it is not giving desired result. create table ac as select username as accountno from all_users / ok, tell me, what is the sorted order of: and I'll keep asking the same tired question over and over. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. In order to group by time, we need to define the granularity level of the time element to group by. I'm working on tuning the system but its difficult since the front end BI application connects directly to the database and generates its own queries based on what the user is click on in the dashboard. great, so write a report -- not everything is doable in a single query every time without some procedural workings on it. *Action: Check the following error message for the cause, and consult your error manual for the appropriate action. Is it possible? TO_DATE (TO_CHAR (D1. Here's the problem- when below code is executed, the time taken to finish the job is more than 4 hours, something around 7 to 8 hours. CLICK HERE. Why doesnt SpaceX sell Raptor engines commercially? By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. we checked the time to get the first rows back(in discoverer). Thanks for contributing an answer to Database Administrators Stack Exchange! Why doesnt SpaceX sell Raptor engines commercially? select * from table( dbms_xplan.display_cursor( null, null, 'ALLSTATS LAST' ) ); So you're doing analytics on a 40 million row set. Can I trust my bikes frame after I was hit by a car if there's no visible cracking? "D_DTM", 'dd') AS "DDTMDAY". Does the policy change for AI-generated content affect users who (want to) Oracle SQL Optimization: SQL Query taking very long time, SQL Query optimization : Taking lots of time. Thanks. Ways to find a safe route on flooded roads. A query went from 5 minutes to 0.3 seconds with DBMS_STATS, I came to the same query (see my answer below), except for : * the subquery has no reason to select DISTINCT orderIDs. Use DBMS_STATS and make sure you also get your indexes, you can set cascade=>true when you gather stats for the table. Talk to your DBA about adding a EXPLAIN PLAN table to your schema, that error is related to not having the plan table. Why does the whole statement take such a long time in Oracle? The fact that restricting the records returned by specifying rownum <= 10 returns quickly but removing it causes your performance issue tells me that it is either trying to return a vast number of records (cartesian product) or that your execution plan has some serious issues, perhaps full table (or large index range) scans of large tables. I am not a guru of optimization, but maybe you also overlooked some indexes in your Oracle database. Now that we have the actual time we know that suggestion is not helpful. Could entrained air be used to increase rocket efficiency, like a bypass fan? Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, What does your estimated execution plan look like? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Regarding the answers, the simpler the better in this case. The best answers are voted up and rise to the top, Not the answer you're looking for? Approximation data in table is more than 100 000. It's We have a consistent problem with them here in that we construct queries that do the selective part well (i.e. Try. A much simpler and safer version of the above is to use ROWNUM. But my comment on the question would be that you need to provide additional information when you are looking for performance help. Normally the implicit distinct would be unecessary overhead, but in this case it would probably be appropriate. For efficiency (same resource, less time). Please find below the query and this is general Oracle Apps HRMS Module EBS query. Is 7 in ( 1, 1, 1, 1, 2, 2, 2, 7 )? But in your tests, both tables were partitioned. Several 100 sessions were queued up resulting in a hang like situation on a critical production database. Update query taking long time to execute dear tom, i am using a query that update a column of one table. *Comment: This error can be turned off with event 10397, in which case the server's actual error is signaled instead. looks like you want to write a report then -- in master/detail style. Edith says: ooops, the query is not well formed, but the general idea is correct. Why are distant planets illuminated like stars, but when approached closely (by a space telescope for example) its not illuminated? There are many factors that determine how the database resolves the query, object statistics, SYS schema statistics, and parameters, as well as server performance. But your solution might produce wrong result set. Hee heeI'm chuckling at my cut-paste fail here :-) But even with a corrected one. (in general, an index on every column being distincted could change that). You can't simply change NOT IN to NOT EXISTS without modifying the subquery. And of course, keep up to date with AskTOM via the official twitter account. Would the query make use of the primary key index somehow to do the sort? . "REV_D_TRANSD_QTY" AS "REVDTRANSDQTY". Connect and share knowledge within a single location that is structured and easy to search. Im waiting for my US passport (am a dual citizen. My source and target tables are identical but constantly in flux as CDC is applying UPDATES, INSERTS, and DELETES from source to target constantly. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. oh..I think I know why now. Ideally the first query should be faster than yours and the second one (replaced the first) should be better than the first one.Remember to keep them separately with notes on performance. DS impact depends on a lot of issues, and you can get information from a DS query that lasts a tiny fraction of a second that can take a query from 10 seconds down to a fraction of a second. Long story short, it's just another tool to understand and appreciate for what it is. Try this: "Although I'm still curious why I have to do this, and if/when I would need to run it again?". much more often used with data My father is ill and booked a flight to see him - can I travel on my other passport? How can I shave a sheet of plywood into a wedge shim? How long do you expect it to take? This is a bad plan, it joins all To learn more, see our tips on writing great answers. Sort out the join between these two tables and it will definitly help. If you get incorrect data, then use correct partition names to look for. Aha! Another way to write the same query would be: However, I would rather expect the query to involve an "orders" table: I think several people have pretty much the right SQL, but are missing a join between the inner and outer queries. Nothing is necessary "bad". In Europe, do trains/buses get transported by ferries with the passengers inside? The table will continue to grow to a much larger size (eventually tens of millions). Could entrained air be used to increase rocket efficiency, like a bypass fan? By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. Each has 100K rows. Oracle also has a feature called 395 row data within 3 hours 37 minutes, I have no idea how to tune this query statement to improve the performance and make it execute faster, and the statistic of rows count for table, Retrieve EXPLAIN PLAN with rerun gather_plan_statistics as @jonearles suggest. D1. Thanks for comment it's necessary for me. D1. Hopefully I've given enough info to help me with this. FROM (SELECT TRUNC (D1. Making statements based on opinion; back them up with references or personal experience. Connor and Chris don't just spend all day on AskTOM. In Europe, do trains/buses get transported by ferries with the passengers inside? For those interested in query tuning and performance and want to learn more some of the google terms to search are "oak table oracle" and "oracle jonathan lewis". My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts. It would be better to perform the HASH GROUP BY first and then only join 1 row from that table. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Now we've identified this, what can we do about it? SQL Server allows only one NULL row in an index except you create a filtered index. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide, Can you please post the Explain Plan output? I was thinking to create an index but I am converting the datetime column to 'yyyymmddhh24' so not sure how to do this in Oracle. By default, using the artificially bad statistics, Oracle joins the tables first and then performs the HASH GROUP BY and HASH UNIQUE. So I removed it and used parallel for huge tables. Two scans of the table might be inefficient though. In SQL Server the whole statement runs quickly. Thanks for contributing an answer to Stack Overflow! Or if video is more your thing, check out Connor's latest video and Chris's latest video from their Youtube channels. D1. Try this, remove the group by and wrap the base query with a simple count, like this select count(*) from (original query); and see how long that runs. The leader of the Wagner military group said his forces had begun to withdraw from the city on Thursday. No it's not. If you have no index over the Engineer1 and Engineer2 columns then you are always going to generate a Table Scan in SQL Server and the equivalent whatever that may be in Oracle. "Like i need to select product_code,dealer_code as grouped columns and distinct, if A is the primary key -- i propose this. distinct values per column, clustering For example, in my earlier comment I suggested looking at the NESTED LOOPS where ROWS=1. Strange periodic group by problems (ORA-00979), SQL GROUP BY ORA-00933: SQL command not properly ended --> Error at offset: 498. "REV_AIR_PER_TRSF_D_QTY" AS "REVAIRPERTRSFDQTY". rev2023.6.2.43474. when you have Vim mapped to always print two? What if the numbers and words I wrote on my check don't match? Each order will be allocated (one or more of its task will have engineer1 and engineer2 set) or the order can be unallocated (all its task have null values for the engineer fields). The "IN" - clause is known in Oracle to be pretty slow. Well it all bears measuring of course. I agree with your explanation - I am just posting my query . DBMS_STATS is a more robust way. "DO_SECT_PHL_REV_PS_TMS" AS "DOSECTPHLREVPSTMS". I have a table t containing three fields accountno, tran_date, amount and amount is always > 0. I agree, this is obsolete. Should I include non-technical degree and non-engineering experience in my software engineer CV? Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. How to divide the contour to three parts with the same arclength? DELETES are a bit more problematic because a DELETE can occur for ANY record, recent or old. "dynamic sampling" that is used to potential performance increase for a When the row estimates are far off, find the first part of the execution plan where the cardinality is wrong. Aggregation is happening too late in the execution plan. To artificially make a bad plan, statistics are gathered too soon on TEST2. D1. The three different schemas have the different subset of data's and when I run the query to retrieve the data from schema1 and schema3 in schema2, the performance is getting ve We ran it in from SQL Plus and Discoverer. Did you manage to get Run time? How common is it to take off from a taxiway? What is going on and how can we improve the performance? New comments cannot be posted to this locked post. And then you can distinct. TEST2 contains 100000 rows, but only one distinct number. yes, break is a sqlplus reporting format. If you decide to create an ORDERS table, I'd add an ALLOCATED flag to it, and create a bitmap index. Is there a faster algorithm for max(ctz(x), ctz(y))? select count (distinct empid),e.group_nm,d.date, from emp e,dept_hist d where e.deptno = d.deptno and e.up_ts > sysdate -30 and e.stat_cd between 100 and 200 and e.group_nm like '%EMPNO%' and employee_id =1 The results from TEST2 go through a HASH GROUP BY right away, as they should. Why are mountain bike tires rated for so much lower pressure than road bikes? Can the logo of TSR help identifying the production time of old Products? What is this object inside my bathtub drain that is causing a blockage? Does the policy change for AI-generated content affect users who (want to) Oracle SQL Optimization: SQL Query taking very long time, Oracle - performance issue. Optimizing a simple query on a large table, Mysql Query takes forever after adding a where condition, Equality Range Query in MySQL runs very slowly. I have a query where I can't seem to figure out why its taking so long to group the records(I think thats the issue). By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I tried the NOT EXISTS version of the statement but it ran for over 3 minutes before I cancelled it. It means too many Parallels. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. D1. FROM LOANIAMRR ll WHERE LOANIAMRR_ENTITY_NUM = 1 AND ll.LOANIAMRR_ACNT_NUM=l.LNACNT_INTERNAL_ACNUM GROUP BY ll.LOANIAMRR_ACNT_NUM) WHERE l . Can Bluetooth mix input from guitar and send it to headphones? rev2023.6.2.43474. [As I write, Tom has not followed up, so I dare to contribute.]. Why does bunched up aluminum foil become so extremely hard to compress? * drop the "orderID" between WHERE and NOT EXISTS (syntax error). I think the best answer is not one that meets your criteria and that is write a different statement for each platform that is best for that platform. Making statements based on opinion; back them up with references or personal experience. How to improve the query? "I don't like it when it is rainy." which can be then rewritten using joins as: I agree with TZQTZIO, I don't get your query. query group by taking a long time k1ng87 Jul 30 2013 edited Jul 31 2013 I'm running Oracle 11g right now on a quarter rack exadata box. Can anyone help me understand why its taking so long (takes about 10 minutes to return results) to group these records together (again, i'm assuming the grouping and sorting is the issue). plans against the way that the data Women over 5'11''?) it'll be a function of your SORT_AREA_SIZE if you are using 8i and before -- pga_aggregate_target | sort_area_size in 9i and up. This could be done with NVL2, but would likely not be portable to SQL Server. "D_DTM", 'yyyymmdd'). "DO_SECT_PHL_FWD_PS_TMS" AS "DOSECTPHLFWDPSTMS". Plan IDs 6 through 40 represent the first half of the inline view, before the UNION. Forget about the first one try the second one. You can do this by; alter session set timed_statistics=all; . Why doesnt SpaceX sell Raptor engines commercially? I don't know it isn't spoken of more often. Sqlserver vs. Oracle isn't the problem here. Making statements based on opinion; back them up with references or personal experience. You can also catch regular content via Connor's blog and Chris's blog. Not the answer you're looking for? I updated my question. I realized the CASE statement in the GROUP BY might slow things down, so I tried removing it for testing purposes (it has to be there for production use, though): Much better, but it still is a pretty slow query. Query With GROUP BY/DISTINCT Statement Is Taking Long Time To Execute. The difference between the benefits of different techniques almost always comes down to the value distributions of a particular data set and the presence or absence of indexes and constraints. I'm working on tuning the system but its difficult since the front end BI application connects directly to the database and generates its own queries based on what the user is click on in the dashboard. Based on what happened . Dropping a user takes long time and hangs, with DBRM enabled and the user is part of a Consumer group (Doc ID 2225074.1) Last updated on OCTOBER 10, 2022. Should convert 'k' and 't' sounds to 'g' and 'd' sounds when they follow 's' in a word for pronunciation? 3 I'm not very experienced with MySQL and and trying to figure out how to speed up a slow query using GROUP BY and CASE statements. Asking for help, clarification, or responding to other answers. also try to select your view separately to see how much time it takes. Diagonalizing selfadjoint operator on core domain. the second one will be more performant in general as well. If it does, that's probably where your problem is. The GROUP BY clause is often used with aggregate functions such as AVG (), COUNT (), MAX (), MIN () and SUM (). The GROUP BY clause returns one row per group. example, the number of rowsin a table, Given additional information in the comments, I would expect it to take a long time. I would strongly encourage you to not do that, do not use to_char to truncate a date, use trunc. What are good reasons to create a city/nation in which a government wouldn't let you leave. I am trying to find all the orderIDs that are unallocated. Creating knurl on certain faces using geometry nodes. 576), AI/ML Tool examples part 3 - Title-Drafting Assistant, We are graduating the updated button styling for vote arrows. Tyler Hicks/The New York Times. Making statements based on opinion; back them up with references or personal experience. If you re-write your query using MINUS, it is likely to run quite quickly: What proportion of the rows in the table meet the condition "engineer1 IS NOT NULL AND engineer2 IS NOT NULL"? Umm -- the columns in a group by clause are dictated PURELY by the question being asked. ORA-00904: "OID2": invalid identifier. I got task to improve existing code / query from my company. Also, they should be able to help you through the plan as well, so you can get an idea about where to start looking for the problems in the query. Can Bluetooth mix input from guitar and send it to headphones? IN is not always bad and there are likely cases which one could show it actually performs better than EXISTS. Another option is to use MINUS (EXCEPT on MSSQL). I have a query which is taking very long time as it has some aggregate functions and Group By Clause. Here's an article on how to rewrite your subqueries with join : How does one show in IPA that the first sound in "get" and "got" is different? when you have Vim mapped to always print two? The query is below as its veeerrry long and the stuff in where clause is generated by the application. Is Spider-Man the only Marvel character that has been represented as multiple non-human characters? rev2023.6.2.43474. rev2023.6.2.43474. 12 I'm trying to run the following SQL statement in Oracle, and it takes ages to run: SELECT orderID FROM tasks WHERE orderID NOT IN (SELECT DISTINCT orderID FROM tasks WHERE engineer1 IS NOT NULL AND engineer2 IS NOT NULL) If I run just the sub-part that is in the IN clause, that runs very quickly in Oracle, i.e. (These hints are really tricky - the reason I used a group by instead of another distinct in my sample is because I had so much trouble with the PLACE_DISTINCT hint!). Semantics of the `:` (colon) function in Bash when used in a pipe? CASE 1 -- GROUP BY and CASE SELECT SQL_NO_CACHE m.id, m.sku, m.movie_url FROM movie.movies m WHERE m.s_id = 1 GROUP BY m.mg_id, CASE WHEN m.mg_id IS NULL THEN m.id ELSE 0 END LIMIT 100 Remove the parallel from view or alter session set sort_area_size = 1,048,576,000; -- 1 Gig, I agree that Oracle date comparisons works, but no index cannot be used because it is invalidated with the trunc function (unless you create a function-based index on trunc(date). E-Rows and A-Rows are off by an order of magnitude: Step 36 has a complex predicate that involves SYSDATE. Insufficient travel insurance to cover the massive medical expenses for a visitor to US? The solution to this would be to re-write the query in a way that would allow a function based index to be created that only includes the null value rows. Yes, GROUP BY on Primary Keys will result in only one row, but my case is when multiple tables are joined. How does one show in IPA that the first sound in "get" and "got" is different? Sub-queries are "bad" with Oracle. rev2023.6.2.43474. 1. Can't get TagSetDelayed to match LHS when the latter has a Hold attribute set, How to make a HUE colour node with cycling colours. Not only do you have a cartesian product between latrep.ADDRESSES and BILL_HISTORY which is more than likely killing the performance of your query but you have also neglected to specify a date format for your TO_DATE functions Forget subqueries, joins, distinct and group bys, they are not needed at all! The total count - 10183462 and it took 74.995 sec after doing count(*) from the base query . Asking for help, clarification, or responding to other answers. Thanks for contributing an answer to Database Administrators Stack Exchange! :), Building a safer community: Announcing our new Code of Conduct, Balancing a PhD program with a startup career (Ep. The capture of the eastern Ukrainian city of Bakhmut by the . It depends on how critical are the queries for the application. At 40 million rows, this may take a while. Those extra steps are mostly just passing data through and shouldn't slow things done much. Share and learn SQL and PL/SQL; free access to the latest version of Oracle Database! What does Bell mean by polarization of spin state? Living room light switches do not work during warm/hot weather. What is "too much time"? How to speed up slow query using GROUP BY and CASE? VS "I don't like it raining.". Asking for help, clarification, or responding to other answers. You would have an index and a not null constraint on a column so the count(*) is faster; And if possible create_time would have a create_day column; If 2 not possible, partition table by create_time column; and the index becomes local. Potential Solution #2: Force a plan with ROWNUM. If we assume the query did make sense then you might want to try using EXISTS as some suggest and avoid IN. How to divide the contour to three parts with the same arclength? "NORM_CONN_CLS_CNT" AS "NORMCONNCLSCNT". mean? Learn more about Stack Overflow the company, and our products. * drop the 'print("code sample"), obviously ;-), When I try the second query it gets an error? if an employess can have >1 row with "unique data". Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Is there a faster algorithm for max(ctz(x), ctz(y))? Making statements based on opinion; back them up with references or personal experience. "Explain PLAN FOR" did't work . sampling it outweighed by the Thanks Tom. Potential Solution #3: Fix cardinality estimates and hope for the best. lowest values per column, number of First, create two simple tables. use the expected indexes and return the data quickly) but when we aggregate using GROUP BY, the queries "go away and return hours later." "REV_AIR_PER_BAD_FRM_CNT" AS "REVAIRPERBADFRMCNT". Asking for help, clarification, or responding to other answers. My statement seems to run indefinitely, Oracle SQL Optimization: SQL Query taking very long time. Lilypond (v2.24) macro delivers unexpected results, "I don't like it when it is rainy." After Oracle Database Resource Manager (DBRM) configuration, dropping users are taking extremely long time to complete.User being dropped was holding a 'X' mode 'Library Cache Lock' on the resource consumer group object, which was blocking all other users who want'S' mode lock on this object. D1. Hi Sir This query is taking 7 hours to execute in prod server.Actually dept_hist have huge amount of records.as it is a history table. How does TeX know whether to eat this space if its catcode is about to change? though i am using it parallel. This is similar to the plan that would be produced if the statistics were accurate. Would it help if you created a column on that table CASE WHEN m.mg_id IS NULL THEN m.id ELSE 0 END, then indexed on it? Find centralized, trusted content and collaborate around the technologies you use most. How can I shave a sheet of plywood into a wedge shim? Is it possible? The Oracle documentation contains a complete SQL reference. Typically, the engineer fields will be foreign keys, so the indexes should be there. Query using groupby, SQL Query optimization : Taking lots of time, Optimizing an Oracle group by/aggregate query, How to improve the performance of SQL query in Oracle DB. The optimizer thinks that TEST2 only has one row but it really has 100000. @Mac: Oooops, 'print("code sample")', hmmm my only excuse is that I'm working on a new laptop and didn't see it :) - thanks for your hints! the average width of rows, highest and can anyone please help me how to sort out this issue? How can I manually analyse this simple BJT circuit? The COUNT() function does not count NULL values. This is called subquery unfolding I think and it's different from the query block unparsing which is used for distributed queries. It's generally better do use joins. "I don't like it when it is rainy." Can Bluetooth mix input from guitar and send it to headphones? Movie in which a group of friends are driven to an abandoned warehouse full of vampires. Goal Following query is slow. I am trying to run a couple of reconciliation queries to identify missed deletes from our change data capture tool, but I need it to run relatively fast My source and target tables are identical but constantly in flux as CDC is applying UPDATES, INSERTS, and DELETES from source to target constantly. ), I think there is a forgotten condition for joining. When you add the group by, the database will have to read in all rows for the query because it will have to aggregate all rows before any single row could be returned. What does Bell mean by polarization of spin state? I need to "group by" by B.PRIME_UID, after ths I had this error: I added all columns to "group by" and it works. There are many potential improvements to any moderately complicated SQL statement. "SITES_GEO_HIERARCHY" D2, LEFT OUTER JOIN "DMSN". Is Spider-Man the only Marvel character that has been represented as multiple non-human characters? What if the numbers and words I wrote on my check don't match? Asking for help, clarification, or responding to other answers. Your second proposal is NOT the same thing, since there can be multiple tasks per orderID, some assigned and some not. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. The data model, some sample data, and some additional data volumes on the tables involved. Share. Can you generate an execution plan with runtime stats. This tells you (roughly) whether it might be worth trying to use an index to retrieve the associated orderid's. Unfortunately, this trick requires extra code and generates extra steps in the plan. What does "Welcome to SeaWorld, kid!" I tried cretaing an Index for the columns used in the GROUP BY clause, but no difference. "SESS_CONF_SXS_CNT" AS "SESSCONFSXSCNT". Incredible, after I ran this it took just under 1 second to run my original SQL statement. Oracle incorrectly thinks it's better to join everything first and perform one SORT UNIQUE, instead of performing multiple SORT UNIQUE or HASH GROUP BY and combining the results. select extract (hour from sold_at) as hour, sum (revenue) as total_revenue from sales group by extract (hour from sold . If the index was on city, country -- you would have no need to add the extra and most like very confusing group by column. see above, your query is wrong, the order by must be on the OUTER query, not in the inline view. This is an obsolete syntax for collecting statistics. Hmm, no, it still gives the same error tried in SQL Plus and Toad Freeware. Oracle group by too long time Ask Question Asked 11 years, 10 months ago Modified 10 years, 8 months ago Viewed 3k times 1 I have this Query: If the query speeds up drastically by removing one table, then that's where your problem is and we know where to work on fixing it. then by all means use distinct. Why doesnt SpaceX sell Raptor engines commercially? But I think creation of MV itself will take time (and space) as size of my table t is in TB. tell me -- do you want distinct rows -- is that your goal? But when you add the group by/aggregation, you are now waiting for the whole thing. You've got this later to try to narrow it down, but I suspect the OR is causing it to have to do a full table scan and cartesian product before it can match any of the criteria: Try pulling BILL_HISTORY out of the query entirely and see if performance improves significantly. The GROUP BY clause is used in a SELECT statement to group rows into a set of summary rows by values of columns or expressions. This can be a very difficult method but it can pay off in multiple ways. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The GROUP BY must produce no more than 100,000 buckets, Oracle query taking a very long time to execute, Building a safer community: Announcing our new Code of Conduct, Balancing a PhD program with a startup career (Ep. If you just need the Orders that have unallocated tasks then the following should work just fine on both platforms, but you should also consider adding the indexes to the Tasks table to improve query perfomance. But once it's in place fast refreshes should be quick provided you do them on commit/regularly. Find centralized, trusted content and collaborate around the technologies you use most. I'm running Oracle 11g right now on a quarter rack exadata box. How much of the power drawn by a chip turns into heat? Hi,Below is my SQL Query & Execution Plan. made my original SQL statement execute much faster. For example, one query took 4.5 seconds to select 350K records, however when we add some AVG functions and GROUP BY the query flys off to neverneverland and returns 2 plus hours later. What happens if you've already found the item an old map leads to? For faster just throw more parallels at it. Also dont use Order by which overkills the query run time. TEST1 has numbers from 1 to 100000. The tasks only has an index on the orderID and taskID. "SITES_SYS_HIERARCHY" D3, WHERE TRUNC (D1. I'll guess, are you running this in toad or something. Otherwise you spend more time sampling that doing. Noise cancels but variance sums - contradiction? Please advice if any other way it can be written to improve its performance . . and what is the "desired order", give us a "for example". Is there a place where adultery is a crime? I'm new to posting here. How to divide the contour to three parts with the same arclength? It was keep on running , however the subquery flat data comes up quickly in seconds in SQL developer . (And then go see your DBA to get EXPLAIN PLAN working, it's really a necessity to solve issues like this. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. A group by with a having clause is the best way to write this query. - 40 Million. When there is a ROWNUM Oracle cannot move the distinct and group by because it would affect that order. What is this object inside my bathtub drain that is causing a blockage? Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Or if video is more your thing, check out Connor's latest video and Chris's latest video from their Youtube channels. For this plan, it appears to be plan ID 36. cost-based optimzer information that Fully reproducing this problem without a full export is almost impossible. Instead of: AND B.BILL_DT >= to_date('2011-07-01'), Use: AND B.BILL_DT >= to_date('2011-07-01', 'YYYY-MM-DD'). Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. the default under 10g. Before you added the group by, you were running a query that probably returned fairly quickly as it executed the query then fetched a subset of rows, 200-500, depending on your client tool. But I was trying to simplify the question by not including it in the original SQL statement. CASE 3 -- Without GROUP BY and without CASE. For larger What happens if you've already found the item an old map leads to? Also I change the query, please test this and let us know the result. The chc subquery includes a group by and count. The issue we have is to identify those situations when the CDC tool does not replicate some database log activity from Oracle to Synapse. To learn more, see our tips on writing great answers. rev2023.6.2.43474. That will make it take an eternity. Building a safer community: Announcing our new Code of Conduct, Balancing a PhD program with a startup career (Ep. Why do I get different sorting for the same query on the same data in two identical MariaDB instances? And you can only have in your select clause (part of the query) directly what you have in the group by clause. How much of the power drawn by a chip turns into heat? Note, I tried Analyze today and it didn't do anything. Without an explain plan its hard to say for sure, but I think the problem is related to this: You've got a Cartesian Product there. try to use, also you should post all tables description into question, After try to switch off and on here there result 576), AI/ML Tool examples part 3 - Title-Drafting Assistant, We are graduating the updated button styling for vote arrows, MySQL COUNT Query taking too long time to execute, Incremental extract strategy using SSIS and CDC, How to make a HUE colour node with cycling colours. Yes, be careful, the minus statement uses alot of memory. Does the policy change for AI-generated content affect users who (want to) How can I speed up a joined update in SQL? Groups and calculated items allow you to add new "members" to a column, when those members do not exist in the data source. Asking for help, clarification, or responding to other answers. Is there a reason beyond protection from potential corruption to restrict a minister's ability to personally relieve and appoint civil servants? What maths knowledge is required for a lab-based (molecular and cell biology) PhD? Connect and share knowledge within a single location that is structured and easy to search. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Depending on the amount of data, you would have OK SELECT performance but unexpected UPDATE degradation at any given time. Unfortunately it did not seem to help at all, but +1 for trying. In fact, the internal query optimizer in Oracle cannot handle statements with "IN" pretty good. Without the GROUP BY statement, the above times drop further. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. still searching how to get the run time without run that query. statistics at execution time. Query :-----SELECT RP_INSTR_CC.NAME, INSTRUMENT.COMPLETE. Is there a legal reason that organizations often refuse to comment on an issue citing "ongoing litigation"? Either way the best method for testing this if you cannot generate an explain plan is to remove the table BILL_HISTROY from your query temporarily to see if performance increases, if so you have identified the problem. Try to support your answer, yes you right look like statement try to take archived_date in future I change my answer, thank you, Let OP get back on table stats.. my suspect is on range partitions which might be on date Also ORDER BY, DISTINCT, lack of parallel hints zzzz, @Galbarad i try to run by edit what you mention above, and remove all DISTINCT keyword, but still not help, @user2982040 try switch off one of union select with 1=0 and check with select take more time (maybe one of them fast and you need optimize only one), Query statement consume quite long time on execution on oracle, docs.oracle.com/cd/B28359_01/server.111/b28274/ex_plan.htm, Building a safer community: Announcing our new Code of Conduct, Balancing a PhD program with a startup career (Ep. I am on 11g and the statement is on a PARTITIONED table (HASH Partitioning). Plan IDs 4 and 5 generate 13 billion rows and account for 95% of the execution time. Get us an explain plan and we can give you a more definite answer. How does TeX know whether to eat this space if its catcode is about to change? 576), AI/ML Tool examples part 3 - Title-Drafting Assistant, We are graduating the updated button styling for vote arrows. I guess that in the original SQL statement the sub-query is run every time for each row in the first part of the SQL statement - even though it is static and should only need to be run once? Thanks for contributing an answer to Stack Overflow! i try to run that query and got this message ORA-12801: error signaled in parallel query server P007 ORA-01652: unable to extend temp segment by 128 in tablespace TEMP 12801. I'll never understand why programmers so often put DISTINCT in their IN clauses. For larger implementations you usually have to weigh the stability of the execution plans against the way that the data changes, which is a tricky balance. The code below only demonstrates how Oracle can incorrectly merge aggregation operations. try using "EXISTS": Caution: Please check if the query builds the same data results. Two attempts of an if with an "and" are failing: if [ ] -a [ ] , if [[ && ]] Why? How can an accidental cat scratch break skin but not damage clothes? Why does bunched up aluminum foil become so extremely hard to compress? Hopefully, the pending deletes will CATCH UP and we match up. Is there a faster algorithm for max(ctz(x), ctz(y))? How many rows does your subquery retrieve? To subscribe to this RSS feed, copy and paste this URL into your RSS reader. You can create a group or calculated item as a way to display data in a table, pivot table, trellis, or graph. Is it OK to pray any five decades of the Rosary or do they have to be in the specific set of mysteries? Living room light switches do not work during warm/hot weather. SELECT ptcd.region, ptcd.phone, COUNT (*) calls. The Oracle optimizer does a good job of processing MINUS statements. You have not provided me with enough information for me to help you. Use the "AS oid2" I inserted, it was not in the query before. Oracle incorrectly believes the number of rows will be smaller, and that earlier aggregations should be merged together. "NORM_SESS_RLS_CNT" AS "NORMSESSRLSCNT". Although I'm still curious why I have to do this, and if/when I would need to run it again? @Dave, only if your queries are big and infrequent. Since you've gone away for your Easter holidays, I thought I'd take the time to do a more complete test and give you something for when you get back. I'm not very experienced with MySQL and and trying to figure out how to speed up a slow query using GROUP BY and CASE statements. How to make use of a 3 band DEM for analysis? Extending IC sheaves across smooth divisors with normal crossings. This example is only one possible source of cardinality mismatches. How can I shave a sheet of plywood into a wedge shim? Why wouldn't a plane start its take-off run from the very beginning of the runway to keep the option to utilize the full runway if necessary? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. 576), AI/ML Tool examples part 3 - Title-Drafting Assistant, We are graduating the updated button styling for vote arrows, EXPLAIN output suggests that my index is not being used. By clicking Post Your Answer, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct. What are good reasons to create a city/nation in which a government wouldn't let you leave. D1. factor of indexes etc. ROWNUM is a pseudocolumn that represents the order of the rows returned. Classes, workouts and quizzes on Oracle Database technologies. I'm trying to run the following SQL statement in Oracle, and it takes ages to run: If I run just the sub-part that is in the IN clause, that runs very quickly in Oracle, i.e. changes, which is a tricky balance. If it is, please let us know via a Comment, https://livesql.oracle.com/apex/livesql/s/f9vohc0s7vlm6pm4viur2rehk, https://blogs.oracle.com/sql/12-things-developers-will-love-about-oracle-database-12c-release-2#real-time-mv. Intuition behind large diagrams in category theory. Meanwhile, I would suggest you remove all the. Scrub as needed to protect the information. Optimising a SELECT query that runs slow on Oracle which runs quickly on SQL Server, download.oracle.com/docs/cd/B19306_01/server.102/b14211/, http://www.dba-oracle.com/sql/t_rewrite_subqueries_performance.htm, Building a safer community: Announcing our new Code of Conduct, Balancing a PhD program with a startup career (Ep. The statistics give Oracle's Japan's stock market has waited more than three decades for its moment in the sun. This would be a better comparison than just running the original query alone. In a small database you can just setup Thanks. Is Spider-Man the only Marvel character that has been represented as multiple non-human characters? VS "I don't like it raining.". Connect and share knowledge within a single location that is structured and easy to search. Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. Yes, creating the MV will take time. and leave it alone. But, we didn't know that any column that is there in the ORDER BY clause but not in the SELECT list should also be there in the GROUP BY clause of a query. In fact, this is Theoretical Approaches to crack large files encrypted with AES. To learn more, see our tips on writing great answers. But perhaps I am missing something, if one assigned engineer is enough not to list the order then change the left join to read as: LEFT JOIN tasks t1 ON t.orderID = t1.orderID AND (t1.engineer1 IS NOT NULL OR t1.engineer2 IS NOT NULL) But that would be different from your original query. you probably meant order by "trans_unique DESC" (from big to small) in the second query. distinct -- think about it. It's much more often used with data warehouses where the overhead of the sampling it outweighed by the potential performance increase for a long-running query. The table contents are like, ahh, the infamous EAV model (entity-attribute-value). it needs to determine the efficiency Semantics of the `:` (colon) function in Bash when used in a pipe? Why is Bb8 better than Bc7 in this position? SQL Query optimization : Taking lots of time. Optimize long running select query against Oracle database, Intuition behind large diagrams in category theory. What indications are there that this query should execute faster than it currently does? VS "I don't like it raining.". The country's major stock indexes are trading at highs not seen since 1990, when its infamous asset bubble of . 2.Switch off 2nd where condition. Please try to avoid using it. need not take long but can be very valuable. I could set this query up in one Oracle database and make it run slow and make it run fast in another. Tom, I have a table with values like id, value. W hen Prince Harry gives evidence in the Mirror phone-hacking trial on Tuesday, he will become the first senior royal to be cross-examined in court since the 19th century. The subquery is actually executed during soft parsing time, thus multiple executions of the same child cursor may potentially return wrong results if resultset of the subquery changes (unless Oracle always forces another full parse of these cursors somehow - in which case you can end up with library cache/shared pool latch contention if misusing this feature). Instead use DBMS_STATS instead. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. weigh the stability of the execution How can I manually analyse this simple BJT circuit? Connect and share knowledge within a single location that is structured and easy to search. Connect and share knowledge within a single location that is structured and easy to search. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. How can I get Oracle to have a better execution plan for this query? This index will help the WHERE and GROUP BY, I figured you should change the GROUP BY to ORDER BY because you are not doing any actual aggregation (i.e., you not doing SUM(), COUNT(), AVG(), or any other summations). The Query is taking very long time. It only takes a minute to sign up. The precompute_subquery hint will take subquery text out of the subquery section, fire it separately (before running main query) in a recursive call context, fetch the results and pass these to main query "filter" condition as a list of OR conditions. The application is also nesting initial query inside of a query that does a group by. Is there any philosophical theory behind the concept of object in computer science? And of course, keep up to date with AskTOM via the official twitter account. The statistics give Oracle's cost-based optimzer information that it needs to determine the efficiency of different execution plans: for example, the number of rowsin a table, the average width of rows, highest and lowest values per column, number of distinct values per column, clustering factor of indexes etc. Group by is taking very long time in SQL Query in Oracle, Building a safer community: Announcing our new Code of Conduct, Balancing a PhD program with a startup career (Ep. D1. You have also not provided additional insight as to how fast you think this should return. When I use group in my query to get the Sum of few columns, it starts taking too much of time . Just in case it makes any difference, there are ~120k rows in the table, and 3 tasks per order, so ~40k different orders. (Although in general you should still be skeptical of a plan with large tables but ROWS=1.). To learn more, see our tips on writing great answers. To attain moksha, must you be born as a Hindu? Before rewriting the query, could you please reply with plan and run time for this query? How can an accidental cat scratch break skin but not damage clothes? sample tables to determine relevant These members are also known as "custom members." A group is a static list of members that you select or a . add "AND tasks.orderID = orders.orderID"). Aside from humanoid, what other body builds would be viable for an (intelligence wise) human-like sentient species? Switch off 1st where condition, 3.Switch off 3rd where condition , it started to long running, so i guess the select query at 2nd condition taken long time on execution.
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