--source include/no_valgrind_without_big.inc # Tests for setting innodb-page-size=32k; --source include/have_innodb.inc --source include/have_innodb_32k.inc call mtr.add_suppression("Innodb: Cannot add field.*row size is"); let $MYSQLD_DATADIR= `select @@datadir`; --echo # Test 1) Show the page size from Information Schema SELECT variable_value FROM information_schema.global_status WHERE LOWER(variable_name) = 'innodb_page_size'; --echo # Test 4) The maximum row size is dependent upon the page size. --echo # Redundant: 16315, Compact: 16318. --echo # Compressed: 16318, Dynamic: ?. --echo # Each row format has its own amount of overhead that --echo # varies depending on number of fields and other overhead. SET SESSION innodb_strict_mode = ON; --replace_regex /> [0-9]*/> max_row_size/ --error 1005 CREATE TABLE t1 ( c01 char(200), c02 char(200), c03 char(200), c04 char(200), c05 char(200), c06 char(200), c07 char(200), c08 char(200), c09 char(200), c10 char(200), c11 char(200), c12 char(200), c13 char(200), c14 char(200), c15 char(200), c16 char(200), c17 char(200), c18 char(200), c19 char(200), c20 char(200), c21 char(200), c22 char(200), c23 char(200), c24 char(200), c25 char(200), c26 char(200), c27 char(200), c28 char(200), c29 char(200), c30 char(200), c31 char(200), c32 char(200), c33 char(200), c34 char(200), c35 char(200), c36 char(200), c37 char(200), c38 char(200), c39 char(200), c40 char(200), c41 char(200), c42 char(200), c43 char(200), c44 char(200), c45 char(200), c46 char(200), c47 char(200), c48 char(200), c49 char(200), c50 char(200), c51 char(200), c52 char(200), c53 char(200), c54 char(200), c55 char(200), c56 char(200), c57 char(200), c58 char(200), c59 char(200), c60 char(200), c61 char(200), c62 char(200), c63 char(200), c64 char(200), c65 char(200), c66 char(200), c67 char(200), c68 char(200), c69 char(200), c70 char(200), c71 char(200), c72 char(200), c73 char(200), c74 char(200), c75 char(200), c76 char(200), c77 char(200), c78 char(200), c79 char(200), c80 char(200), c81 char(63) ) ROW_FORMAT=compressed; # # Test the maximum key length # Moved from innodb-index.test since each page size has its own max key length. # Max Key Length is 3072 for 16k pages. # Max key Part length is 767 # InnoDB assumes 3 bytes for each UTF8 character. # CREATE TABLE t1 (a varchar(255) character set utf8, b varchar(255) character set utf8, c varchar(255) character set utf8, d varchar(255) character set utf8, e varchar(4) character set utf8, PRIMARY KEY (a,b,c,d,e)) ENGINE=innodb; DROP TABLE t1; --error ER_TOO_LONG_KEY CREATE TABLE t1 (a varchar(255) character set utf8, b varchar(255) character set utf8, c varchar(255) character set utf8, d varchar(255) character set utf8, e varchar(5) character set utf8, PRIMARY KEY (a,b,c,d,e)) ENGINE=innodb; CREATE TABLE t1 (a varchar(255) character set utf8, b varchar(255) character set utf8, c varchar(255) character set utf8, d varchar(255) character set utf8, e varchar(255) character set utf8, f varchar(4) character set utf8, PRIMARY KEY (a), KEY (b,c,d,e,f)) ENGINE=innodb; DROP TABLE t1; --error ER_TOO_LONG_KEY CREATE TABLE t1 (a varchar(255) character set utf8, b varchar(255) character set utf8, c varchar(255) character set utf8, d varchar(255) character set utf8, e varchar(255) character set utf8, f varchar(5) character set utf8, PRIMARY KEY (a), KEY (b,c,d,e,f)) ENGINE=innodb; --echo # Test 8) Test creating a table that could lead to undo log overflow. CREATE TABLE t1(a blob,b blob,c blob,d blob,e blob,f blob,g blob, h blob,i blob,j blob,k blob,l blob,m blob,n blob, o blob,p blob,q blob,r blob,s blob,t blob,u blob, v blob, w blob, x blob, y blob, z blob, aa blob,ba blob,ca blob,da blob,ea blob,fa blob,ga blob, ha blob,ia blob,ja blob,ka blob,la blob,ma blob,na blob, oa blob,pa blob,qa blob,ra blob,sa blob,ta blob,ua blob, va blob, wa blob, xa blob, ya blob, za blob) ENGINE=InnoDB ROW_FORMAT=dynamic; SET @a = repeat('a', 767); SET @b = repeat('b', 767); SET @c = repeat('c', 767); SET @d = repeat('d', 767); SET @e = repeat('e', 767); # With no indexes defined, we can update all columns to max key part length. INSERT INTO t1 VALUES (@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a,@a); UPDATE t1 SET a=@b,b=@b,c=@b,d=@b,e=@b,f=@b,g=@b,h=@b,i=@b,j=@b, k=@b,l=@b,m=@b,n=@b,o=@b,p=@b,q=@b,r=@b,s=@b,t=@b,u=@b, v=@b,w=@b,x=@b,y=@b,z=@b, aa=@b,ba=@b,ca=@b,da=@b,ea=@b,fa=@b,ga=@b,ha=@b,ia=@b,ja=@b, ka=@b,la=@b,ma=@b,na=@b,oa=@b,pa=@b,qa=@b,ra=@b,sa=@b,ta=@b,ua=@b, va=@b,wa=@b,xa=@b,ya=@b,za=@b; # With this many indexes defined, we can still update all fields. CREATE INDEX t1a ON t1 (a(767)); CREATE INDEX t1b ON t1 (b(767)); CREATE INDEX t1c ON t1 (c(767)); CREATE INDEX t1d ON t1 (d(767)); CREATE INDEX t1e ON t1 (e(767)); CREATE INDEX t1f1 ON t1 (f(767)); CREATE INDEX t1f2 ON t1 (g(767)); CREATE INDEX t1f3 ON t1 (h(767)); CREATE INDEX t1f4 ON t1 (i(767)); CREATE INDEX t1f5 ON t1 (j(767)); UPDATE t1 SET a=@c,b=@c,c=@c,d=@c,e=@c,f=@c,g=@c,h=@c,i=@c,j=@c, k=@c,l=@c,m=@c,n=@c,o=@c,p=@c,q=@c,r=@c,s=@c,t=@c,u=@c, v=@c,w=@c,x=@c,y=@c,z=@c, aa=@c,ba=@c,ca=@c,da=@c,ea=@c,fa=@c,ga=@c,ha=@c,ia=@c,ja=@c, ka=@c,la=@c,ma=@c,na=@c,oa=@c,pa=@c,qa=@c,ra=@c,sa=@c,ta=@c,ua=@c, va=@c,wa=@c,xa=@c,ya=@c,za=@c; # Add one more index and the UNDO record becomes too big to update all columns. # But a single transaction can update the columns in separate statements. # because the UNDO records will be smaller. CREATE INDEX t1f17 ON t1 (v(767)); BEGIN; UPDATE t1 SET a=@d,b=@d,c=@d,d=@d,e=@d,f=@d,g=@d,h=@d,i=@d,j=@d, k=@d,l=@d,m=@d,n=@d,o=@d,p=@d,q=@d,r=@d,s=@d,t=@d,u=@d, v=@d,w=@d,x=@d,y=@d,z=@d, aa=@d,ba=@d,ca=@d,da=@d,ea=@d,fa=@d,ga=@d,ha=@d,ia=@d,ja=@d, ka=@d,la=@d,ma=@d,na=@d,oa=@d,pa=@d,qa=@d,ra=@d,sa=@d,ta=@d,ua=@d, va=@d,wa=@d,xa=@d,ya=@d,za=@d; ROLLBACK; BEGIN; UPDATE t1 SET a=@d,b=@d,c=@d,d=@d,e=@d; UPDATE t1 SET f=@d,g=@d,h=@d,i=@d,j=@d; UPDATE t1 SET k=@d,l=@d,m=@d,n=@d,o=@d; UPDATE t1 SET p=@d,q=@d,r=@d,s=@d,t=@d,u=@d; UPDATE t1 SET v=@d,w=@d,x=@d,y=@d,z=@d; UPDATE t1 SET aa=@d,ba=@d,ca=@d,da=@d; UPDATE t1 SET ea=@d,fa=@d,ga=@d,ha=@d,ia=@d,ja=@d; UPDATE t1 SET ka=@d,la=@d,ma=@d,na=@d,oa=@d,pa=@d; UPDATE t1 SET qa=@d,ra=@d,sa=@d,ta=@d,ua=@d; UPDATE t1 SET va=@d,wa=@d,xa=@d,ya=@d,za=@d; COMMIT; # More indexes can still be added and a single field can still be updated CREATE INDEX t1k ON t1 (k(767)); CREATE INDEX t1f7 ON t1 (m(767)); CREATE INDEX t1f8 ON t1 (n(767)); CREATE INDEX t1f9 ON t1 (o(767)); CREATE INDEX t1f11 ON t1 (p(767)); CREATE INDEX t1f12 ON t1 (q(767)); CREATE INDEX t1f13 ON t1 (r(767)); CREATE INDEX t1f14 ON t1 (s(767)); CREATE INDEX t1f15 ON t1 (t(767)); CREATE INDEX t1f16 ON t1 (u(767)); CREATE INDEX t1f18 ON t1 (w(767)); CREATE INDEX t1f19 ON t1 (x(767)); CREATE INDEX t1f20 ON t1 (y(767)); CREATE INDEX t1f21 ON t1 (z(767)); CREATE INDEX ta1a ON t1 (aa(767)); CREATE INDEX tb1b ON t1 (ba(767)); CREATE INDEX tc1c ON t1 (ca(767)); CREATE INDEX td1d ON t1 (da(767)); CREATE INDEX te1e ON t1 (ea(767)); CREATE INDEX tf1f1 ON t1 (fa(767)); CREATE INDEX tg1f2 ON t1 (ga(767)); CREATE INDEX th1f3 ON t1 (ha(767)); CREATE INDEX ti1f4 ON t1 (ia(767)); CREATE INDEX tj1f5 ON t1 (ka(767)); CREATE INDEX tk1f6 ON t1 (la(767)); CREATE INDEX tl1f7 ON t1 (ma(767)); CREATE INDEX tm1f8 ON t1 (na(767)); CREATE INDEX tn1f9 ON t1 (oa(767)); CREATE INDEX to1f11 ON t1 (pa(767)); UPDATE t1 SET t=@e; # One more index and row size is too big (not any more!) #--replace_regex /> [0-9]*/> max_row_size/ #--error ER_TOO_BIG_ROWSIZE CREATE INDEX t1f6 ON t1 (l(767)); drop table t1; --echo Test an assertion failure on purge. # This test is not in innodb_8k or innodb_4k since the bug is not about # page size. It just tests the condition that caused the assertion. CREATE TABLE t1_purge ( A int, B blob, C blob, D blob, E blob, F blob, G blob, H blob, PRIMARY KEY (B(767), C(767), D(767), E(767), A), INDEX (A) ) ENGINE=InnoDB ROW_FORMAT=DYNAMIC; INSERT INTO t1_purge VALUES (1, REPEAT('b', 766), REPEAT('c', 766), REPEAT('d', 766), REPEAT('e', 766), REPEAT('f', 766), REPEAT('g', 766), REPEAT('h', 766)); CREATE TABLE t2_purge ( A int PRIMARY KEY, B blob, C blob, D blob, E blob, F blob, G blob, H blob, I blob, J blob, K blob, L blob, INDEX (B(767))) ENGINE=InnoDB ROW_FORMAT=DYNAMIC; INSERT INTO t2_purge VALUES (1, REPEAT('b', 766), REPEAT('c', 766), REPEAT('d', 766), REPEAT('e', 766), REPEAT('f', 766), REPEAT('g', 766), REPEAT('h', 766), REPEAT('i', 766), REPEAT('j', 766), REPEAT('k', 766), REPEAT('l', 766)); CREATE TABLE t3_purge ( A int, B varchar(800), C varchar(800), D varchar(800), E varchar(800), F varchar(800), G varchar(800), H varchar(800), PRIMARY KEY (B(767), C(767), D(767), E(767), A), INDEX (A) ) ENGINE=InnoDB ROW_FORMAT=DYNAMIC; INSERT INTO t3_purge SELECT * FROM t1_purge; CREATE TABLE t4_purge ( A int PRIMARY KEY, B varchar(800), C varchar(800), D varchar(800), E varchar(800), F varchar(800), G varchar(800), H varchar(800), I varchar(800), J varchar(800), K varchar(800), L varchar(800), INDEX (B(767))) ENGINE=InnoDB ROW_FORMAT=DYNAMIC; INSERT INTO t4_purge SELECT * FROM t2_purge; # This would trigger the failure # if purge gets a chance to run before DROP TABLE t1_purge, .... DELETE FROM t1_purge; DELETE FROM t2_purge; DELETE FROM t3_purge; DELETE FROM t4_purge; # A secondary index tuple is found to be too long to fit into a page. SET @r=REPEAT('a',500); CREATE TABLE tlong(a int, v1 varchar(500), v2 varchar(500), v3 varchar(500), v4 varchar(500), v5 varchar(500), v6 varchar(500), v7 varchar(500), v8 varchar(500), v9 varchar(500), v10 varchar(500), v11 varchar(500), v12 varchar(500), v13 varchar(500), v14 varchar(500), v15 varchar(500), v16 varchar(500), v17 varchar(500), v18 varchar(500) ) ENGINE=InnoDB ROW_FORMAT=DYNAMIC; CREATE INDEX idx1 ON tlong(a,v1); INSERT INTO tlong VALUES(9,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r,@r); UPDATE tlong SET a=1000; DELETE FROM tlong; # the number of indexes has changed since the UNDO record was logged. # page size. It just tests the condition that caused the crash. CREATE TABLE tlong2(a blob,b blob,c blob,d blob,e blob,f blob,g blob,h blob, i blob,j blob,k blob,l blob,m blob,n blob,o blob,p blob) ENGINE=innodb ROW_FORMAT=dynamic; SET @r = REPEAT('a', 767); INSERT INTO tlong2 VALUES (@r,@r,@r,@r, @r,@r,@r,@r, @r,@r,@r,@r, @r,@r,@r,@r); CREATE INDEX ndx_a ON tlong2 (a(500)); CREATE INDEX ndx_b ON tlong2 (b(500)); CREATE INDEX ndx_c ON tlong2 (c(500)); CREATE INDEX ndx_d ON tlong2 (d(500)); CREATE INDEX ndx_e ON tlong2 (e(500)); CREATE INDEX ndx_f ON tlong2 (f(500)); CREATE INDEX ndx_k ON tlong2 (k(500)); CREATE INDEX ndx_l ON tlong2 (l(500)); SET @r = REPEAT('b', 500); UPDATE tlong2 set a=@r,b=@r,c=@r,d=@r; UPDATE tlong2 set e=@r,f=@r,g=@r,h=@r; UPDATE tlong2 set i=@r,j=@r,k=@r,l=@r; UPDATE tlong2 set m=@r,n=@r,o=@r,p=@r; ALTER TABLE tlong2 DROP INDEX ndx_a; ALTER TABLE tlong2 DROP INDEX ndx_b; CREATE INDEX ndx_g ON tlong2 (g(500)); CREATE INDEX ndx_h ON tlong2 (h(500)); CREATE INDEX ndx_i ON tlong2 (i(500)); CREATE INDEX ndx_j ON tlong2 (j(500)); CREATE INDEX ndx_m ON tlong2 (m(500)); CREATE INDEX ndx_n ON tlong2 (n(500)); CREATE INDEX ndx_o ON tlong2 (o(500)); CREATE INDEX ndx_p ON tlong2 (p(500)); SHOW CREATE TABLE tlong2; # InnoDB cannot know that this undo record would be too big for the undo # page. Too much of text field is stored in the clustered record in this # DYNAMIC row formatted record. SET SESSION innodb_strict_mode = ON; CREATE TABLE t3( a int NOT NULL, b blob NOT NULL, c text, PRIMARY KEY (b(10), a), INDEX (c(767)), INDEX(b(767)) ) ENGINE=InnoDB ROW_FORMAT=DYNAMIC; INSERT INTO t3 VALUES (5,REPEAT('khdfo5AlOq',1900),REPEAT('g',7751)); COMMIT; UPDATE t3 SET c = REPEAT('b',16928); SHOW WARNINGS; UPDATE t3 SET c = REPEAT('b',32800); SHOW WARNINGS; DROP TABLE t3; # The tests that uses these tables required the purge thread to run. # Just in case it has not by now, provide a 10 second wait. --sleep 10 DROP TABLE t1_purge, t2_purge, t3_purge, t4_purge; DROP TABLE tlong; DROP TABLE tlong2; CREATE TABLE t2(COL1 TEXT, COL2 TEXT, COL3 TEXT, COL4 TEXT, COL5 TEXT, COL6 TEXT, COL7 TEXT, COL8 TEXT, COL9 TEXT, COL10 TEXT, COL11 TEXT, COL12 TEXT, COL13 TEXT, COL14 TEXT, COL15 TEXT, COL16 TEXT, COL17 TEXT, COL18 TEXT, COL19 TEXT, COL20 TEXT, COL21 TEXT, COL22 TEXT, COL23 TEXT, COL24 TEXT, COL25 TEXT, COL26 TEXT, COL27 TEXT, COL28 TEXT, COL29 TEXT, COL30 TEXT, COL31 TEXT, COL32 TEXT, COL33 TEXT, COL34 TEXT, COL35 TEXT, COL36 TEXT, COL37 TEXT, COL38 TEXT, COL39 TEXT, COL40 TEXT, COL41 TEXT, COL42 TEXT, COL43 TEXT, COL44 TEXT, COL45 TEXT, COL46 TEXT, COL47 TEXT, COL48 TEXT, COL49 TEXT, COL50 TEXT, COL51 TEXT, COL52 TEXT, COL53 TEXT, COL54 TEXT, COL55 TEXT, COL56 TEXT, COL57 TEXT, COL58 TEXT, COL59 TEXT, COL60 TEXT, COL61 TEXT, COL62 TEXT, COL63 TEXT, COL64 TEXT, COL65 TEXT, COL66 TEXT, COL67 TEXT, COL68 TEXT, COL69 TEXT, COL70 TEXT, COL71 TEXT, COL72 TEXT, COL73 TEXT, COL74 TEXT, COL75 TEXT, COL76 TEXT, COL77 TEXT, COL78 TEXT, COL79 TEXT, COL80 TEXT, COL81 TEXT, COL82 TEXT, COL83 TEXT, COL84 TEXT, COL85 TEXT, COL86 TEXT, COL87 TEXT, COL88 TEXT, COL89 TEXT, COL90 TEXT, COL91 TEXT, COL92 TEXT, COL93 TEXT, COL94 TEXT, COL95 TEXT, COL96 TEXT, COL97 TEXT, COL98 TEXT, COL99 TEXT, COL100 TEXT, COL101 TEXT, COL102 TEXT, COL103 TEXT, COL104 TEXT, COL105 TEXT, COL106 TEXT, COL107 TEXT, COL108 TEXT, COL109 TEXT, COL110 TEXT, COL111 TEXT, COL112 TEXT, COL113 TEXT, COL114 TEXT, COL115 TEXT, COL116 TEXT, COL117 TEXT, COL118 TEXT, COL119 TEXT, COL120 TEXT, COL121 TEXT, COL122 TEXT, COL123 TEXT, COL124 TEXT, COL125 TEXT, COL126 TEXT, COL127 TEXT, COL128 TEXT, COL129 TEXT, COL130 TEXT, COL131 TEXT, COL132 TEXT, COL133 TEXT, COL134 TEXT, COL135 TEXT, COL136 TEXT, COL137 TEXT, COL138 TEXT, COL139 TEXT, COL140 TEXT, COL141 TEXT, COL142 TEXT, COL143 TEXT, COL144 TEXT, COL145 TEXT, COL146 TEXT, COL147 TEXT, COL148 TEXT, COL149 TEXT, COL150 TEXT, COL151 TEXT, COL152 TEXT, COL153 TEXT, COL154 TEXT, COL155 TEXT, COL156 TEXT, COL157 TEXT, COL158 TEXT, COL159 TEXT, COL160 TEXT, COL161 TEXT, COL162 TEXT, COL163 TEXT, COL164 TEXT, COL165 TEXT, COL166 TEXT, COL167 TEXT, COL168 TEXT, COL169 TEXT, COL170 TEXT, COL171 TEXT, COL172 TEXT, COL173 TEXT, COL174 TEXT, COL175 TEXT, COL176 TEXT, COL177 TEXT, COL178 TEXT, COL179 TEXT, COL180 TEXT, COL181 TEXT, COL182 TEXT, COL183 TEXT, COL184 TEXT, COL185 TEXT, COL186 TEXT, COL187 TEXT, COL188 TEXT, COL189 TEXT, COL190 TEXT, COL191 TEXT, COL192 TEXT, COL193 TEXT, COL194 TEXT, COL195 TEXT, COL196 TEXT, COL197 TEXT) row_format=dynamic,ENGINE=INNODB; set @a = repeat('0123456789', 800); set @b = repeat('9876543210', 800); insert into t2 values( @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a); update t2 set col190=@b; set @a = repeat('0123456789', 1650); set @b = repeat('9876543210', 2000); insert into t2 values( @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a,@a,@a,@a, @a,@a,@a,@a,@a,@a,@a); update t2 set col190=@b; # # Verify persistence and loading of flags in the ibd files. # --source include/restart_mysqld.inc set @a = repeat('abcdefghijklmnopqrstuvwxyz', 1650); set @b = repeat('zyxwvutsrqponmlkjihgfedcba', 2000); show create table t2; update t2 set col150=@a; update t2 set col145=@b; drop table t2;