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April 2019

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[Maria-discuss] Row vs Statement Replication in 10.3
by mariadb＠biblestuph.com 02 Apr '19

02 Apr '19

Using binlog-format=MIXED I'm trying to get my head around why certain statements are being written as RBR instead of as a statement. On my 10.3 test server running a fraction of my full load binary logs are getting written to the tune of about 30M/minute (the 5.5 production server with a currently much heavier load writes about 8.5M/minute). All of the tables are currently MyISAM. Here's a couple examples: This always gets written as a statement in 10.3: UPDATE mydb.t1 SET rundate = '2019-03-28 23:04:00' , runtime = UTC_TIMESTAMP() , runstatus = 1 WHERE hostname = 'my.host.com' While this always gets written as a row: UPDATE mydb.t1 SET rundate = '2019-03-28 23:04:00' , runtime = UTC_TIMESTAMP() , runstatus = 10 WHERE hostname = 'my.host.com' If it matters, runstatus (the only difference in the two) is a TINYINT(3) UNSIGNED NOT NULL DEFAULT 0. Both statements are written as statements in 5.5. And this one always gets written as RBR on 10.3, but I don't see why. I reviewed the information at https://mariadb.com/kb/en/library/unsafe-statements-for-statement-based-rep… but can't seem to see what is triggering it. UPDATE mydb.t1 AS i LEFT JOIN mydb.t2 AS j1 ON ( i.f1 = j1.f1 ) LEFT JOIN mydb.t3 AS j2 ON ( i.f1 = j2.f1 AND i.f2 > 0 AND i.f2 = j2.f2 ) SET i.f3 = IF ( i.f2 < 0, IF ( j1.f3 IS NULL, i.f3, j1.f3 ), IF ( j2.f3 IS NULL, i.f3, j2.f3 ) ) , i.f4 = IF ( i.f2 < 0, IF ( j1.f3 IS NULL, i.f4, j1.f3 ), IF ( j2.f3 IS NULL, i.f4, j2.f3 ) ) WHERE i.f5 != 0 AND i.f2 != 0 AND i.f6 = 1 AND i.f7 = 0 The 10.3 logs don't offer anything by way of explanation, presumably because I have it set to MIXED. Looking at it I see I can use a COALESCE instead of the inner IFs, but I'm still unclear why it must be row-based. Thanks, Dan

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