case studies on postgresql

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Technical Case Studies in PostgreSQL[ Monitoring Methods ]

Rohit Vyas | 11.04.15

Quality Management Group (PostgreSQL Installer and Tools)


• Technical cases in PostgreSQL

• Database Monitoring Methods

Agenda


− Bloats− Updates/Deletes cause bloats in a table in

PostgreSQL.

− Transaction Wraparound− No new XID’s if 4 billion mark reached.

− Streaming/WAL Replication Lag− Number of bytes lag from Master database may

be due to bulk load, network etc.,

− Handling WAL Archiving Files− Piling up .ready files due to failure of archiver

process

− Catalog Corruption− Database objects repository(pg_catalog schema)

corruption.

Technical Cases on Production Database

ERROR: database is not accepting commands to avoid

wraparound data loss in database "dvnspatial"

Hint: Stop the postmaster and use a standalone

backend to vacuum that database.

You might also need to commit or roll back old prepared

transactions.

Error executing update (updateorg.matter.security.User)

PANIC: could not write to file

“pg_xlog/xlogtemp.556” :No space left on

device

notice: pg_class row has invalid relnamespace "24580":

no matching entry in pg_namespace

row identity: oid="24581" relname="foo" relkind="r"


• Using pg_catalog Tables/Views/Functions

• Wrapping pg_catalog in Shell or any scripting language.

• Using open source tools − check_postgres.pl, pg_catcheck, pg_cluu, munin, Nagios etc

• Proprietary Tools − EnterpriseDB Postgres Enterprise Manager

Database Monitoring Methods


• Tables− pg_class

− pg_database

• Views− pg_stat_activity

− pg_stat_all_tables

− pg_stat_archiver

− pg_stat_replication

• Functions− pg_is_in_recovery()

− pg_last_xlog_replay_location()

− pg_last_xact_replay_timestamp()

− pg_xlog_location_diff()

Using pg_catalogs


Wrapping pg_catalogs in Shell or Other languages

Max Connections

Long Running queries

Idle Connections

Waiting Connections


• check_postgres.pl

• pg_catcheck [ catalog corruption ]

• pg_cluu

Using open source tools


Sample output of critical probes on Production Environment


pg_catcheck


Monitoring with Proprietary Tools

• Postgres Enterprise Manager [ EnterpriseDB] PostgreSQL

Instances of different versions

9.0.x

9.1.x9.4.x

9.3.x

9.2.x

PEM

Server


PEM Probes And Alerts

Table Bloat Total table bloat in server

Highest Table Bloat in server

Table Frozen XID Table FrozenXID

Database Frozen XID Database FrozenXID

Number of WAL Files Number of WAL Files

WAL Archive status Number of WAL archiving Pending

Streaming Replication Standby server lag behind the master By WAL

segment

Standby server lag behind the master by WAL

pages

Streaming Replication Lag Number of minutes lag in standby server from

master server


Dashboard's Charts


PEM Alerts


• Complete point and click management of all database objects

• 225+ pre-configured database alerts for immediate global at-a-glance monitoring complete with SMTP notifications, SNMP traps and richly configurable notification rules (New)

• Remote Monitoring (New)

• A Capacity Planning and Forecast Manager

• PostgreSQL Expert database configuration recommendations and deployment

• Log Management and a Log Analysis Expert (New)

• Team Management

• Custom probes for gathering metrics (New)

• SQL Profiler

• Index Advisor

• All optimized for working with multiple databases consistently across the enterprise.

Primary Product Features


• On Premise Server

• Public Cloud [AWS]

• Private Cloud [Open stack ]

Deployment


References

• http://www.enterprisedb.com/products-services-training/products/postgres-enterprise-manager

Postgres Enterprise Manager


Questions?

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