…Tables – Names, number of children, parents, count of columns, row counts, and comments — a great way for a high level overview of the table…
Post: Understanding the maximum number of columns in a MySQL table
April 8, 2013 By 5 Comments
…in a file name. Back in 1979, Monty developed an in-house database…sql.=”`$n`”; $sql.=” ENUM(‘”.cname(0,64).”‘) COMMENT ‘”.cname($_,254).”‘,\n”; } chop $sql; chop $sql; $sql.=”);”; print $sql; So the maximum number of columns for a table in…
Post: Why MySQL could be slow with large tables ?
June 9, 2006 By 141 Comments
…number of CPUs will not help. Sometimes it is good idea to manually split query into several, run in…servers to host portions of data set. Store portion of data you’re going to work with in temporary table etc. Prefer full table…
Post: Shard-Query turbo charges Infobright community edition (ICE)
May 6, 2011 By 23 Comments
…single table). In order to demonstrate the power of Shard-…of a single commodity database server with 6 cores (+6ht) and 24GB of…. This same SQL script was used in the Shard…servers, it performs about 6x better as the degree of parallelism is controlled by the number of shards. — Q9 select Year ,count…
Post: SHOW INNODB STATUS walk through
July 17, 2006 By 40 Comments
…number of tables used by transaction in question (meaning it was accessed) and number of tables locked by transactions. Innodb does not lock tables for normal operation so number of tables…number of pages in buffer pool, number of pages free, pages allocated by database…
Post: MySQL caching methods and tips
April 4, 2011 By 5 Comments
…of change in the database tables. This results in…servers with many cores, a high volume of queries can cause extensive mutex contention. Percona Server even has a state in…of pages is a good way to reduce the number of round trips to the cache. Summary tables Queries that access a lot of…
Post: MySQL Query Cache
July 27, 2006 By 70 Comments
…server which runs this blog. Updates are rather rare so per-table granularity is not the problem, I have only one server and number of…in chunks so it is even harder to implement. Might not work with transactions – Different transactions may see different states of the database…
Post: Sphinx: Going Beyond full text search
July 23, 2007 By 18 Comments
…counting number of links (and number number of distinct forum sites) pointing to the given URL or graphs showing number of…SQL databases rather than full text search applications. Group By was added to Sphinx so we could search number of matches per day, or number of…
Post: Debugging problems with row based replication
May 6, 2010 By 12 Comments
…of data to play with: select count(*) from t1; +———-+ | count(*) | +———-+ | 65536 | +———-+ 1 row in…server id 1 end_log_pos 340678 Table_map: `repl`.`t1` mapped to number 15 #100506 12:42:56 server…
Post: Analyzing air traffic performance with InfoBright and MonetDB
October 2, 2009 By 50 Comments
….bts.gov/DL_SelectFields.asp?Table_ID=236&DB_Short_Name…build number (revision)=IB_3.2_GA_5316(ice) MonetDB version: server v5.14…I generated big SQL file which contained load statements. Load of each chunk… in different queries. First favorite query for any database benchmarker is SELECT count(*) FROM…
