Hopefully someone here can give me some theories on whats up with some ssrs instability ive faced lately... This has happened across several servers I administer for customers with heavy reporting uses. I'll give details for a specific example that happened today as its details are fresh in my mind and hopefully someone can give me some ideas on where to look... somewhere in the 7am window on sunday, report performance went from 5-8 seconds on avg for a particular report to 90 seconds. It wasnt table stats, it wasnt memory pressure, or anything like that. the 'solution' was to restart ssrs. As I went through the SSRS history, I noticed that almost all reports were affected in the same way. Their avg durations all returned to normal after the issue was reported to me and I restarted SSRS as a 'maybe that will fix it cause I dont see anything else wrong' shot in the dark.The server has 2014sp1, 64b of ram, 48max memory for sql server and had 13gb available at the time of the restart today. the SSRS process was at about 1.3gb. this was a full 24 hours after the problem began. perf instantly returned to 'good' with a restart. These reports were still completing, just in 10x or more their normal duration. after the restart, ssrs climbed to 3gb+ of memory and was flying through them. ssrs memory wasnt high around the time of the problem starting.Nothing apparent in error logs, no cpu pressures on the server, IO throughput was very steadily acceptable, nothing in ssrs logs to give me any clues...EXCEPT...I notice that SSRS went through its every 12 hour AppDomain unload routines around the time this problem arose. It did the same 3 more times before the problem was reported to us. Could that be related?Im scheduling an SSRS Restart daily now, and have some monitoring on report history of critical reports so we can at least get a quicker heads up if ths happens again.... however... what would cause this pattern of ALL reports behaving badly until an SSRS restart, then they work fine for weeks on end? The timing of this doesnt correlate with any patterns, subscriptions, resource spikes or anything else I can identify. any help or suggestions anyone could offer would be fantastic.
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