Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

Differences between BDR and trigger-based replication

-

There are a number of trigger-based logical replication solutions for PostgreSQL, including Londiste, Slony-I and Bucardo. They're mature, fairly widely used and powerful, and like BDR they have the advantages (and disadvantages) of logical replication.
As with the comparison with physical replication, BDR offers advantages over trigger-based replication solutions but also has some downsides.
All trigger-based replication solutions suffer from inherent write-amplification, where each write to the database produces a corresponding write to a replication log table. Both the original write and the write to the replication log get recorded in WAL as well as the heap, so each write actually happens four times. By reading and processing WAL for data to replicate BDR avoids this write amplification, so writes to a BDR-replicated database only get written twice - like any other durable write on PostgreSQL.
Trigger-based replication also requires an external dæmon process on the sending and/or receiving side. BDR runs its management processes inside PostgreSQL itself, so there's no separate replication process to manage.
At the time of writing, systems like Londiste have a number of features for which BDR has no corresponding capability. Londiste can synchronise and compare tables between the publisher and subscriber. Slony-I supports events and confirmations. Slony-I provides infrastructure for handling DDL while also running on unmodified PostgreSQL 9.4. Bucardo supports multi-master on unmodified PostgreSQL 9.4. So while BDR offers some significant benefits it won't suit every need and every workload. Evaluate your needs carefully before choosing a technology.

Comments

Post a Comment

Popular posts from this blog

How to Configure User Equivalence (Key-Based Authentication) on Linux

-
Installation The SSH service should already be installed, but if it is not, install it from a Yum repository using the following command. # yum install openssh-server Turn on the SSH service and make sure it starts automatically on reboot. # service sshd start # chkconfig sshd on The SSH service is configured using the "/etc/ssh/sshd_config" file. Configuration changes have to be followed by a restart of the service. # service sshd restart # # or # service sshd reload Firewall The server must have the TCP port 22 open. This can be achieved by adding the following entry to the type of firewall script described  here . # Open port for NTP server. iptables -A INPUT -p tcp --dport 22 -j ACCEPT SELinux If you are using SELinux, you will need to consider the following points. The SELinux booleans associated with the SSH service are displayed using the  getsebool  command. # getsebool -a | grep ssh allow_ssh_keysign --> off fenced_can_ssh --> off ssh...
Read more

VMWARE WORKSTATION 3,4,5,6,7,8,9,10,11,12,14,15...etc LICENSE KEYS COLLECTION

-
Image
Below tutorialdba.com collected and sorted out hundreds of universal License Keys for all major versions of VMware Workstation Pro (not for VMware Workstation Player) 4.x, 5.x, 6.x, 7.x, 8.x, 9.x, 10.x, 11.x, 12.x and v14.x on Windows and Linux platforms (support both 32-bit and 64-bit operating system) in this single post. Besides, we also provide some license keys for VMware other projects. Just enjoy and share them. // 4~14 Universal License Keys // Version License Keys VMware Workstation VMware Workstation 4.x.x ZHDH1-UR90N-W844G-4PTN6 G1NP0-T88AL-M016F-4P8N2 ZC14J-4U16A-0A04G-4MEZP J1WF8-58LDE-881DG-4M8Q3 VMware Workstation 5.x.x LUXRM-WP0DN-A256U-4M9Q3 DJXDR-NDT27-Y2NDU-4YTZK DA925-HP80U-Z8HDC-4WXXP 3KW2W-AYR2C-88M6F-4MDQ2 VMware Workstation 6.x.x A0E8R-YUDFV-6AK2F-4GAN2 CRX0D-VWL0V-7CJ6C-46C7A NA8RX-QPNDU-D2LA9-4WAZL 1H4WM-N21FZ-7GK2A-44U5U 6AJ6N-THY2P-42KEF-4WTFG FK8R9-LPCDT-88H4Y-4WRN3 KAR8R-T8MAL-K8J6A-4WDXQ YJEKW-JMFF4-YA1DC-4WTQ...
Read more

How to Get Table Size, Database Size, Indexes Size, schema Size, Tablespace Size, column Size in PostgreSQL Database

-
In this post, I am sharing few important function for finding the size of database, table and index in PostgreSQL. Finding object size in postgresql database is very important and common. Is it very useful to know the exact size occupied by the object at the tablespace. The object size in the following scripts is in GB. The scripts have been formatted to work very easily with PUTTY SQL Editor. 1. Checking table size excluding table dependency: SELECT pg_size_pretty(pg_relation_size('mhrordhu_shk.mut_kharedi_audit')); pg_size_pretty ---------------- 238 MB (1 row) 2. Checking table size including table dependency: SELECT pg_size_pretty(pg_total_relation_size('mhrordhu_shk.mut_kharedi_audit')); pg_size_pretty ---------------- 268 MB (1 row) 3. Finding individual postgresql database size SELECT pg_size_pretty(pg_database_size('db_name')); 4. Finding individual table size for postgresql database -including dependency index: SELECT pg_size_pretty(pg_total_rel...
Read more

Postgres Database Patch

-
If you are used to patch Oracle databases you probably know how to use opatch to apply PSUs. How does PostgreSQL handle this? Do we need to patch the existing binaries to apply security fixes? The answer is: No.Lets say you want to patch PostgreSQL from version 10.5/11.3 to version 10.10/11.5. This is called minor version postgres upgrade or postgres patching Why need to patch postgresql server  ? Multiple SQL injection vulnerabilities have been discovered in PostgreSQL that could allow for arbitrary code execution. The vulnerabilities are the result of the application’s failure to sufficiently sanitize user-supplied input before using it in an SQL query. These vulnerabilities allow attackers with the CREATE permission (or Trigger permission in some tables) to exploit input sanitation vulnerabilities in the pg_upgrade and pg_dump functions. The CREATE permission is automatically given to new users on the public schema, and the public schema is the default schema used on the...
Read more

PostgreSQL Monitoring Tools

-
There are several open sources as well as Paid tools are available as front-end to PostgreSQL. Here are a few of them which are widely used : pgAgent: pgAgent is a job scheduler for PostgreSQL which may be managed using pgAdmin. Prior to pgAdmin v1.9, pgAgent shipped as part of pgAdmin. From pgAdmin v1.9 onwards, pgAgent is shipped as a separate application. pg_statsinfo: Pg_statsinfo in the monitored DB on behalf of the existence of the form, pg_statsinfo regularly collected snaoshot information and stored in the warehouse pgCluu: pgCluu is a PostgreSQL performances monitoring and auditing tool. View reports of all statistics collected from your PostgreSQL databases cluster. pgCluu will show you the entire informations of the PostgreSQL Cluster and the system utilization pgAdmin III: pgAdmin III is THE Open Source management tool for your PostgreSQL databases. Features full Unicode support, fast, multithreaded query and data editting tools and support for all PostgreS...
Read more