postgresql performance tuning parameters

|| Handler_read_prev | 34822001724 || Handler_read_rnd | 405482605 || Handler_read_rnd_next | 18912877839 |+-----------------------+-------------+For each field explanation see http://hi.baidu.com/thinkinginlamp/blog/item/31690cd7c4bc5cdaa144df9c.html, call up the number of query requests completed by the server:Mysql> show global status like ' Com_select ';+---------------+-----------+| variable_name | Value |+---------------+-----------+| Com_select | 222693559 |+---------------+-----------+C

variables like ' max_connections '; +-----------------+-------+| variable_name | Value |+-----------------+-------+| max_connections | 256 |+-----------------+-------+ mysql> show global status like ' Max_used_connections '; Max_used_connections/max_connections * 100%≈85%The maximum number of connections is about 85% of the maximum number of connections, if the ratio is found below 10%, the maximum number of MySQL server connections is set too high. 5, Key_buffer_sizeKey_buffer_size is one of

Index | performance ORA FAQ Performance Tuning Series-- The Oracle (tm) Users ' co-operative FAQ Why would a reverse index to useful when the leading column of the "index is" generated from a sequence? When the first column of the index is generated by the sequence, what is the use of a reverse index? --------------------------------------------------------------

small number of page splits and improve performance. Compress backup option: In server backup, compress is used to reduce Io, but CPU operations are increased. (4). Connection Maximum number of concurrent connection: sets the maximum number of connections. Use query Governor prevent long-running queries: Use the query manager to block time-consuming queries. Allow remote connections to this server: selected by default 2: SQL Server Configurat

mentioned below, you can try to enable the module via Modprobe: /sbin/modprobe tcp_htcp /sbin/modprobe tcp_hybla For the analysis of several algorithms, the details can be referred to the following: TCP congestion control algorithm advantages and disadvantages of the application of environmental performance analysis, but this does not involve the design of satellite communications specifically fo

efficient results. Http://bbs.linuxtone.org/thread-5152-1-1.html3. Operating System-level optimizationA> A 64-bit system can allocate more memory and service tuning to a single process, disable unnecessary services, modify file descriptor restrictions, and reserve more resources for MySQL;B> File System Optimization: XFS is recommended for a separate file system for the data warehouse, which is generally more efficient and reliable.C> enable the noat

1m-2m size, and then set it individually on demand in each session. 4, Read_rnd_buffer_size For sorting and order by operations, it is best to set it to 1M and then set it as a session variable to a larger value in the session. (v) Slow query log A slow query log is a useful feature of MySQL. 1, Log_slow_queries MySQL parameter in the log_slow_queries parameter set it in the My.cnf file, set it to on, by default, MySQL will put the file into the data directory, the file is named "Hostname-slow.

cluster should be slightly smaller than the number of reducer task slotscombiner use : Fully use the merge function to reduce the amount of data passed between map and reduce, combiner run after mapmedian compression : compressing the map output value reduces the amount of conf.setcompressmapoutput (true) before reducing to reduce Setmapoutputcompressorclass (Gzipcodec.class)Custom Writable: If you use a custom writable object or a custom comparator, you must ensure that you have implemented Ra

memory disk Mkdir-p/mnt/ramdisk sudo mount-t tmpfs-o size=4000m tmpfs/mnt/ramdisk/ mv/var/lib/mysql/mnt/ramdisk/mysql 9. Use MYSQL in a NOSQL way B-tree is still one of the most efficient indexes, and all MYSQL is still not obsolete. Using Handlersocket to skip MySQL's SQL parsing layer, MySQL really becomes NOSQL. 10. Other A single query finally increases LIMIT 1, stopping the full table scan.Separating non-"indexed" data, such as separating large articles from storage, d

If you feel your eclipse is slow, you can adjust it by modifying the%eclipse_home%/eclipse.ini file:Adjust the memory of-XMS and-xmx to 512m (512m if your native memory is 1/4,2g):-xms512m-xmx512mThen add the following line parameters at the end of the file: -xx:permsize=96m-xx:maxpermsize=96m-xmn168m-xx:+disableexplicitgcThe speed has improved significantly after the configuration authors have changed. If you want to optimize further, you can refer t

Problem:A system, MySQL database, after the data is large. MySQL CPU utilization is very high, a Test side access to the server when MySQL CPU utilization is 15%, 6 test end of the server when the MySQL CPU occupancy rate is 50%~60%.PS 1: Each Test side of the thing is to insert records, but before inserting will first check whether there is already the same record, some words to update the original record, not directly inserted.PS 2:cpu--pentium Dual E1240 @ 1.60GHZMemory--2gOs--windows 2003Tun

Oracle database(*) PGA composition structure and related data dictionary(*) Soft parsing and hard parsing(*) Set the initial value of the PGATenth. Optimizing temporary space(*) What is temporary data(*) Best practices for managing temporal tablespace(*) Monitoring temporary tablespace(*) Use temporary tablespace groups11th. Impact Optimization Program(*) Optimizer overview(*) affects one of the optimizer behaviors: using hints(*) affects optimizer behavior two: Optimizer statistics(*) affects

currently doing performance analysis of things, not how to contact perf, find a few articles combed a bit, according to the form of problems recorded here. easy to see for yourself. What is perf? Linux Performance Tuning tool, 32 cores above the tool, software performance analysis. Installing perf is very easy in 2.

on static file compression />2. Optimizing the JVM for catalina.shOpen the Tomcat path \bin\ catalina.sh, add at the top, red part please adjust according to the actual situationJava_opts= "-server-showversion-xms12g-xmx12g-xx:permsize=256m-xx:maxpermsize=256m "java_opts= "$JAVA _opts-d64-xx:cicompilercount=8-xx:+usecompressedoops"java_opts= "$JAVA _opts-xx:survivorratio=4-xx:targetsurvivorratio=90"java_opts= "$JAVA _opts-xx:reservedcodecachesize=256m-xx:-useadaptivesizepolicy"java_opts= "$JAVA

Linux server performance is often affected by CPU, memory, disk I/O, network bandwidth, and so on, for each Linux background server developer, it is necessary to master some of the common performance tuning tools. Covering almost every aspect of a system, the tools in the diagram can be described as "Swiss Army Knives" in per