sql temp table performance

rows reserved data index_size unused TB_WCB 9439661 317208 kb 167168 KB 149872 KB 168 KB */ we found that the size before index compression was 329M. And after compression is 149M, the compression ratio is 45%. The effect is also very obvious. Summarize: Compression through tables and indexes. We can reduce the disk space occupied by the table, this is only part of it, and more importantly, reading the same amoun

compression is 167M, the size of the table after compression is only 40% of the original table, the effect is obvious, and because most of the table's fields are only IDs, the relative repetition value is not too much.However, we see that the size of the index varies substantially, so we continue to compress the index:5. Compression indexAlter index idx_tb_wcb_id on Tb_wcbrebuildwith (Data_compression=row)

oracle| temporary table Recently encountered a problem: the previous Time page query Oracle table is normal, but the page has recently been unable to display. Print out the SQL put to pl/sql devoloper execution, the newspaper "cannot through 8 (in the table space XXX) Extend

one or two fields are modified, do not update all fields. Otherwise, frequent calls may cause significant performance consumption and a large number of logs. 10. For tables with more than a large data size (hundreds of rows are larger), we need to perform the join operation by page. Otherwise, the logical read operation will be very high and the performance will be poor. 11. Select count (*) from

; } /// ///User Account/// Public stringUserName {Set;Get; } /// ///User Password/// Public stringPassWord {Set;Get; } /// ///Nickname/// Public stringNickname {Get;Set; } /// ///Encrypted Salt/// Public stringSalt {Set;Get; } /// ///whether to freeze/// Public BOOLIsFrozen {Set;Get; } /// ///Balance/// Public decimalBalance {Set;Get; } /// ///Department/// Public stringDepartme

to the temp table space to successfully Sql> alter tablespace blsp_temp add tempfile ' +dg_ddata_02/racdbdg/datafile/blsp_temp02.dbf ' size 10240M;Tablespace altered.Sql> Query temporary table space, or error Sql> Select file_id,file_name,bytes/1024/1024 mb,status,tablespac

.Copyright (C) 1995, Oracle and/or its affiliates. All rights reserved.Ggsci (yace) 1> info AllProgram Status Group lags at chkpt time Since chkptMANAGER RUNNINGEXTRACT RUNNING extzw 00:00:00 00:00:05EXTRACT RUNNING PMPZW 00:00:00 00:00:05Replicat RUNNING REPZW 00:00:00 00:00:04Ggsci (yace) 2> info REPZWReplicat REPZW last Started 2018-05-10 18:58 Status RUNNINGCheckpoint Lag 00:00:00 (updated 00:00:00 ago)Process ID 98477Log Read Checkpoint file/home/oracle/ogg/ggs12/dirdat/t10000000402018-06-0

Learning Dynamic Performance Table 3-(1)-V $ SQL V $ SQL stores specific SQL statements. One statement can map multiple cursor because the cursor referred to by the object can have different users (for example, 1 ). If multiple cursor (sub-cursor) exist, provide set informa

Because the memory engine does not support Bolb and text types, if the query uses a BLOB or text column and you need to use an implicit temporary table, you will have to use the MyISAM disk staging table, even if there are only a few rows of data.This can result in a serious performance overhead. Even if you configure MySQL to store temporary tables on memory blo

There should be different filegroups in the database before the partition table is created;Assuming the database name is Df17datapro, create the user table UserID, put the first 500,000 data in the primary filegroup, place the 50~100 in the FG1 filegroup, and put more than 100 in the FG2 filegroup1. Add File group Fg1,fg2ALTER DATABASE Df17datapro ADD FILEGROUP FG1ALTER DATABASE df17dataproadd FILEGROUP f

Tags: SELECT test tmp Understanding SQL Hang elevation Image errorLearning content: Basic operations for staging tables and views ... Scope of use of temporary tables and views ... 1. Temporary tables Temporary tables: temporary tables, presumably everyone knows the existence of this concept ... But when should we use the temporary table? When there is a large amount of data in a database, we want to get a

Tags: ase htm end output based on Val COM multi-table connection directlyOriginal: Effect of driving order on performance in multiple table joins in SQL Server The source of this article: http://www.cnblogs.com/wy123/p/7106861.html(It is not the original works right to retain the source, I my book still far to reach, j

Tags: c blog a http ext com Temp table ? Will the stored data be purged automatically at the end of the session or transaction processing? Provide a dedicated data store for each session? Available for all sessions, without affecting the private data for each session if you need to store private data to perform a task, and after the task is executed, the transaction or session endsclears the d

In Oracle9i, the bulk collect method is added for PL/SQL. You can integrate the retrieved records into a batch of Oracle memory tables to improve the performance of the select into, fetch into or returning into clause. Example:Create or replace type performance_obj as object ( Netlatency number (10) ); Create or replace type performance_tab is table of performanc

PHP Query Oracle Temp table, why empty? $dbOracle =oci_connect ("The database connection is normal, the query is not a temporary table is normal");" " " " "END;"; /do not begin to write directly SQL is the same $stid = Oci_parse ($dbOracle, $ORACLESQL);$r =oci_execute ($stid);Print_r ($R);$ORACLESQL = "S

Label:MySQL Temp TableThe MySQL temp table is very useful when we need to save some temporary data. Temporary tables are only visible at the current connection, and when the connection is closed, MySQL automatically deletes the table and frees all space. Temporary tables are added in MySQL version 3.23 and you cannot u

COMMITPRESERVE ROWS asSELECT * fromTEST; operation Example: SQL> CREATEGLOBALTemporary TABLEtmp_test (ID Number, NAMEVARCHAR2( +) ) on COMMITPRESERVE ROWS;TableCreatedsql> INSERT intotmp_testSELECT 1,'Kerry' fromDUAL;1Row Insertedsql> COMMIT;CommitCompletesql> SELECT * fromTmp_test;id NAME---------- ----------------1Kerrysql> INSERT intotmp_testSELECT 2,'Rouce' fromDUAL;1Row Insertedsql> ROLLBACK;RollbackCompletesql> SELECT * fromTmp_test;id

2. mysql also allows you to create temporary tables in memory directly, because it is in memory all the speed will be fast, the syntax is as follows: CREATE Temporary TABLE tmp_table ( Name VARCHAR (Ten) is not NULL, Value INTEGER not NULL ) TYPE = HEAP 3. From the above analysis can be seen that the temporary table data will be emptied, you disconnect the connection will be automatically emptied, but you

there is a problem with the SQL logic, but 10046 there is no trace to the execution plan, but read the logical reading, the slow one should have produced a Cartesian product. After a simple check, SQL logic does not have a problem, people's first feeling is not necessarily reliable.4. I was wondering what led to the implementation plan is not allowed, suddenly think of Rel_oid_classify is a global temporar

int) On Commit Preserve Rows; 2. Transaction-level staging tableA transaction-level temporary table refers to the data in a staging table that exists only during the transaction life cycle. Create Global Temporary Table table_name(xxx int)On Commit Delete Rows; When a transaction ends (commit or rollback), Oracle automatically clears the data from the staging