cassandra write performance tuning

xf master# cd major-mysqltuner-perl-993bc18/#./ mysqltuner.pl You will receive detailed reports and recommended tips for MySQL usage. The following is an example of the output from the default MariaDB installation: MySQL Performance Optimization 15. Optimize and Repair MySQL database Sometimes tables in the MYSQL/MARIADB database can easily crash, especially if the server shuts down unexpectedly, the file system suddenly crashes, or the database is

be sorted, or it can be added to a column (like joins or additions). Any non-indexed item in the ORDER BY statement, or a computed expression, will slow down the query. Double-check the order BY statement to find non-indexed items or expressions that degrade performance. The solution to this problem is to rewrite the order BY statement to use the index, or you can establish another index for the column you are using, and you should absolutely avoid u

may be a little bit small, or too much fragmentation. Query Cache Hit Ratio = (qcache_hits-qcache_inserts)/qcache_hits * 100% Sample server query Cache Fragmentation rate = 20.46%, query cache utilization = 62.26%, query cache Hit Ratio = 1.94%, hit ratio is poor, probably write more frequently, and possibly some fragments. 4 other 4.1 read_buffer_size 4.2 Slow Query Mysql> Show variables like '%slow% '; + —————— + ——-+ | variable_name | Value | + ——

: Specify MySQL server 's hostname, default is localhost-P/--port : Specify port to connect to MySQL server, default is 3306-S/--delay : Updated number of seconds, preset is 5 seconds-d/--db/--database : Specify connected repositories, default is test-b/--batch/--batchmode: Specified as batchmode, each update does not clear the old display results, the update data is displayed on the top, the preset is unset-S/--socket : Specifies to use mysqlsocket direct connection without TCP/IP connection,

Oracle is a high-performance database software. The user can adjust the parameters to achieve the optimization of performance. Performance optimization is mainly divided into two parts: First, the database administrator through the adjustment of system parameters to achieve the goal of optimization; The second is that the developer achieves the adjustment by op

damage, although the build path has this jar, but there will still be loadclass failure, cleanup maven The jar for the local repository directory, modifying the POM (such as adding a blank line) to let the m2e reload.3, CXF has a very good feature, support JavaScript access to SOAP WebService, client access Http://localhost:8080/cxf/HelloWorld?js similar requests, will generate JavaScript Client, JS programming can use this client-provided object, enabling this feature requires the introduction

Tags: DBA optimizationThe tradeoff between performance and securityFor database tuning, there is no absolute performance or absolute security. Just as the fish and the cake can not be the same, it is not fully balanced, like the spear and the shield to eliminate the other long. Here are a few more common factors to make a brief description:1. Diversified control

# The number of worker_processes should be no more than the number of cores of the server's CPU, # Each CPU core of more than 1 worker does not make nginx performance has any promotion worker_processes 4; # The number of file descriptors used for Nginx. This needs to be set up system kernel parameter ' ulimit-n 200000 ' or modify '/etc/security/limits.conf ', reference "High load Linux tuning" Worker_rlimit

released, the data page will not be in the memory of the data cache, This causes the memory problem to be the bottleneck of the disk. PAGEIOLATCH_EX is write data, this is generally the disk write speed obviously keep up, and memory is not directly related. Here is the resource wait time for query pageiolatch_x: Select Wait_type, waiting_tasks_count, Wait_time_ms, Max_wait_time_ms, Signal_wait_time_ms fr

relatively small value, the process and the number of threads is a more appropriate value. System calls are also, each time the system function is called, our code will enter the kernel space, resulting in context switching, this is very resource-intensive, but also try to avoid frequent calls to system functions. Too many context switches means that most of your CPU is wasted in context switching, resulting in less time for the CPU to do serious work, and the CPU not being fully utilized, is u

From a large perspective, Netty performance is mainly reflected in: 1.io threading Model using reactor mode, synchronous non-blocking. This determines that more can be done with the least amount of resources. 2. Memory 0 copies use direct caching 3. Memory pool design application memory can be reused, mainly direct memory. The internal implementation is to manage memory allocations with a binary lookup tree. 4. The serialization processing socket read

1. Check the database space usage to see which tables are consuming larger disk spaceExecute the following statement:SelectO.name, SUM (p.reserved_page_count) asReserved_page_count, SUM (p.used_page_count) asUsed_page_count, SUM ( CaseWhen (p.index_id2) Then (p.in_row_data_page_count+P.lob_used_page_count+p.row_overflow_used_page_count)Elsep.lob_used_page_count+P.row_overflow_used_page_count End) asDataPages, SUM ( CaseWhen (p.index_id2) then Row_countElse 0end) asrowcounts fromsys.dm_db_partiti

rownumObviously, this writing will result in reading the table first, then sorting, and then taking the first 5 records, the plan is as follows:If we write like this, the semantics are the same, but it saves a lot of reading and sorting costs:Select/*+ Index (T1,IDX1_T1) */* from T1 where rownumThe execution plan for this SQL is as follows:As you can see, the SQL does not follow the hint instructions and sequentially scans the IDX1_T1 index, which is

server-side call to the Accept function is actually the connection from the connected accept queue that completes the three-time handshake.The Accept queue and the SYN queue are listen functions to complete the creation of the maintenance./proc/sys/net/core/somaxconn modification Each of the above parameters is actually enough to write an article to analyze, here I just outline the next part of the parameters, note that when modifying the TCP pa

Tuning system performance using SAR in LinuxKeywords: SARThe SAR default is not installed under Linux, we need to install manually, it is generally recommended source mode installation, download similar sysstat-6.1.3.tar.gzYou can then use the Configure make make install.Common formats for the SAR command line:SAR [Options] [-A] [-o file] t [n]In the command line, the N and t two parameters are combined to

problem is always solved, since PHP-FPM does not have a CPU affinity (affinity) binding directive like Nginx, then we can use Taskset binding php-fpm process to fixed cpux to solve the problem:#!/bin/bashcpus=$ (grep-c processor/proc/cpuinfo)pids=$ (ps aux | grep "php-fpm[:] Pool" | awk ' {print $} ')Let I=0For PID in $PIDs; DoCpu=$ (echo "$i% $CPUs" | BC)Let i++TASKSET-PC $CPU $PIDDoneOnce the script is running, let's take a look at how each CPU load is distributed:Shell> mpstat-p all 1 10CPU%

Among many nosql products, what we can see through benchmark is that the write performance is greatly improved, while the read performance has not increased much or even declined from the traditional RDBMS. For example, Cassandra and MongoDB are two outstanding representatives of nosql. The reason may be that the UGC m

Database optimization techniques, what do you do: · Use a persistent connection database to avoid connection overhead. If you cannot use a persistent connection and you are starting many new connections to the database, you may want to change the value of the thread_cache_size variable. See section 7.5.2, "Tuning server parameters." · Always check that all queries do use indexes that have already been created in the table. In MySQL , you can do it wi