Eric Wong 8bfbfa2708 fix signal handling when waiting on queries ... This reverts the single-threaded select() optimization from commits 9a63a587c0 and 0190457dbd. Under Ruby 1.9, the reverted optimization caused signal handlers to be delayed until the socket became readable. Under Ruby 1.8, matters are worse as receiving a signal during select() causes Errno::EINTR to be raised. There is now a (somewhat fragile) spec for testing signal handling during a "SELECT sleep(2)" query. Furthermore, the performance difference I measured on benchmark/thread_alone.rb was negligible (over 1000 iterations) between the two: Ruby 1.8.7-p249 Rehearsal ---------------------------------------------------- select 0.040000 0.020000 0.060000 ( 0.119448) rb_thread_select 0.050000 0.020000 0.070000 ( 0.132091) ------------------------------------------- total: 0.130000sec user system total real select 0.030000 0.030000 0.060000 ( 0.116471) rb_thread_select 0.050000 0.020000 0.070000 ( 0.119874) Ruby 1.9.2-p0 Rehearsal ---------------------------------------------------- select 0.050000 0.030000 0.080000 ( 0.134208) rb_thread_select 0.080000 0.000000 0.080000 ( 0.141316) ------------------------------------------- total: 0.160000sec user system total real select 0.050000 0.020000 0.070000 ( 0.123325) rb_thread_select 0.060000 0.010000 0.070000 ( 0.124075) Benchmarks were performed on an _empty_ mysql2_test table to maximize the relative time for the select(2)-related code path (vs reading data). The test was run on Debian Lenny, x86_64 and a stock 2.6.35.2 Linux kernel. Hardware was a Core2 Duo @ 1.6GHz with the performance CPU governor while on AC power to eliminate CPU speed fluctuations during the test.		2010-08-18 20:13:13 -07:00
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mysql2	fix signal handling when waiting on queries	2010-08-18 20:13:13 -07:00