sql query running slow oracle database

1.1 symptom: the response of database nodes is slow, and some users' services are affected.View database alarm logs and start to displayORA-07445Errors, followed by a large numberORA-04031Errors andORA-00600Error.Check the database logs. The database is still active as follo

Starting from oracle11gr1, The dia0 background process starts to collect Hang analysis information and store it in the hanganalysiscache in the memory. It collects local Hang points every 3 seconds. Starting from oracle11gr1, The dia0 background process starts to collect Hang analysis information and store it in the memory's hang analysis cache. It collects local Hang points every 3 seconds. To diagnose the slow

There are many causes for slow query speed of SQL Server databases. The following are common causes: 1. No index or no index is used (this is the most common problem of slow query and is a defect in programming) 2. Low I/O throughput, resulting in a bottleneck effect. 3. the

) Contains the name of the action that is executing at the time that the SQL statement is first parsed as set by calling D Bms_application_info. Set_action Action_hash Number Hash value of the action is named in the Actioncolumn Serializable_aborts Number Number of times the transaction fails to serialize, producing ORA-08177 errors, totalled through all the child cursors Cpu_time

statement is first parsed as set by calling c6/>.SET_MODULE MODULE_HASH NUMBER Hash value of the module is named in the MODULE column ACTION VARCHAR2(64) Contains the name of the action is executing at the time that the SQL statement is first parsed as set by calling c5/>.SET_ACTION ACTION_HASH NUMBER Hash value of the action that's named in the ACTION column SE

There are many reasons for slow query speed in SQL Server databases. The following are common causes: 1. No index or no index is used (this is the most common problem of slow query and is a defect in programming) 2. Low I/O throughput, resulting in a bottleneck effect. 3. th

optimization problems. Otherwise, the speed may be slow. After hands-on experience, an Optimized SP is hundreds of times more efficient than an optimized SP with poor performance. Iii. content: 1. If developers use tables or views of other databases, they must create a View in the current database to perform cross-database operations. It is best not to directly

of the query table space 　　 Select Tablespace_name,count (tablespace_name) from Dba_free_space GROUP by Tablespace_name Having count (Tablespace_name) >10; Alter tablespace name COALESCE; ALTER TABLE name DEALLOCATE unused; Create or replace view Ts_blocks_v as Select Tablespace_name,block_id,bytes,blocks, ' free spaces ' segment_name from Dba_free_space UNION ALL Select Tablespace_name,block_id,bytes,blocks,segment_name

into' Student 'VALUES('8','Lee 48','123','male',' +','Jingan, Shanghai city'); INSERT into' Student 'VALUES('9','Zhang 39','111','male',' +','Shiyan, Hubei province'); INSERT into' Student 'VALUES('Ten','Lee 40','123','male',' +','Jingan, Shanghai city'); I. Querying 5~10 data MySQL Paging query: SELECT * FROM student limit 5, 10; Oracle Paging query: SELEC

NUMBER Hash value of the action that's named in the ACTION column SERIALIZABLE_ABORTS NUMBER Number of times the transaction fails to serialize, producing ORA-08177 errors, totalled through all the child cursors CPU_TIME NUMBER CPU time (in microseconds) used by the cursor for parsing/executing/fetching ELAPSED_TIME NUMBER Elapsed time (in microseconds) used by the cursor for parsing/executing/fetching

Label:After installing Oracle (64-bit), PL/SQL developer, execute PL/SQL occurs for example the following error:On the Internet, my PL/SQL developer is incompatible with Oracle, that is, PL/SQL does not support 64-bit

MySQL5.6 how to optimize slow query SQL statements -- Introduction to slow logs Recently, a development team complained that the mysql cluster included in our platform was not good and always reported the "heartbeat Error" of mysql and analyzed the logs they collected, no network problems were found between mysql clust

Recently, a development team complained that the mysqlcluster on our platform was not good and always reported mysql heartbeatError. after analyzing the logs they collected, they did not find any network problems between mysqlcluster nodes, however, I found a very interesting phenomenon. Recently, a development team in mysql's sl complained that the mysql cluster included in our platform was not good and always reported the "heartbeat Error" of mysql. I analyzed the logs they collected and found

When MySQL uses the slow query log to locate those SQL statements that perform less efficiently, and start with the--log-slow-queries[=file_name] option, Mysqld writes a full execution time of more than Long_ Query_time The log file of the SQL statement for the second, by lo

Database optimization tutorial (3) Slow query of records and database optimization tutorial Query1. Slow query foundIn the previous section, we made data preparation for slow queries. T

Database optimization tutorial (3) Slow query of records and database optimization tutorial Query1. Slow query foundIn the previous section, we made data preparation for slow queries. T

function to improve the overall performance of the application on the table of grouped queries or sorted queries. Third, if there are multiple columns to be sorted, you need to set up a composite index on those columns. The foreground application needs to be sorted by vendor, purchase order number, and product number, when it generates the day's purchase schedule. At this point, in other words, when the report is generated for the inventory schedule, the three fields are sorted. When this happ

grouping, having is occurring after grouping, meaning that the grouping function is not directly the value of the condition appears after the where, but can appear after having.Example:--Query the SID of a student who has passed all subjects.SELECT SID from Score WHERE grade>=60 the GROUP by Sid;--the wrong wording, the realization of any subject passing students. SELECT SID from Score GROUP by Sid have MIN (grade) >=60; --Group BY student first, set

, before SQL2000, generally do not use the following words: "Is NULL", "23. Use Query Analyzer to view the SQL statement's query plan and evaluate whether the analysis is an optimized SQL. The general 20% of the code occupies 80% of the resources, and the focus of our optimization is these

dictionaries end up with almost $, such as col$,tab$.For a data dictionary table, the data inside is maintained by the database system itself, so although it is possible to use DML statements to modify the content of the data, it is best not to do it yourself, because these tables are used in the database, we sometimes see 604 of the recursive SQL here