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Fix crash in embedded server due to incorrect storage of results

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in the query cache. (Bug #9549)


libmysqld/emb_qcache.h:
  Fix Querycache_stream::use_next_block() to actually use the next
  block and mark blocks as used when it writes to them.
mysql-test/r/query_cache.result:
  Update results.
mysql-test/t/query_cache.test:
  Add new regression test.
libmysqld/emb_qcache.cc:
  Fix calls to use_next_block() to indicate whether we are writing
  to the next block or not.
sql/sql_cache.cc:
  Initialize the first block properly when storing a result in
  the embedded server.
This commit is contained in:
unknown
2005-03-31 19:17:45 -08:00
parent ab77d7d763
commit e7332e64ca
5 changed files with 119 additions and 21 deletions
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45
mysql-test/t/query_cache.test
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@ -684,4 +684,49 @@ repair table t1;
show status like 'qcache_queries_in_cache';
drop table t1;
# Bug #9549: Make sure cached queries that span more than one cache block
# are handled properly in the embedded server.
# We just want a small query cache, so we can fragment it easily
set GLOBAL query_cache_size=64*1024;
# This actually gives us a usable cache size of about 48K
# Each table is about 14K
create table t1 (a text);
insert into t1 values (repeat('abcdefghijklmnopqrstuvwxyz', 550));
create table t2 (a text);
insert into t2 values (repeat('ijklmnopqrstuvwxyzabcdefgh', 550));
# Load a query from each table into the query cache
--disable_result_log
select a from t1; # Q1
select a from t2; # Q2
--enable_result_log
show status like 'Qcache_%_blocks';
# Now the cache looks like (14K for Q1)(14K for Q2)(20K free)
# Flush Q1 from the cache by adding an out-of-order chunk to t1
insert into t1 select reverse(a) from t1;
show status like 'Qcache_%_blocks';
# Now the cache looks like (14K free)(14K for Q2)(20K free)
# Load our new data into the query cache
--disable_result_log
select a from t1; # Q3
--enable_result_log
show status like 'Qcache_%_blocks';
# Now the cache should be like (14K for Q3)(14K for Q2)(14K for Q3)(6K free)
# Note that Q3 is split across two chunks!
# Load Q3 from the cache, and actually pay attention to the results
select a from t1;
flush query cache;
drop table t1, t2;
set GLOBAL query_cache_size=0;