I have the query timeout set too low, but I believe the stats update completed as I see related rows in the stats table.
Both skip and in-list queries run fine - no exceptions. Still null for the guideposts though - is it likely this is due to the timeout in the stats update? -Gary On Fri, Feb 27, 2015 at 12:30 PM, James Taylor <[email protected]> wrote: > See inline. Thanks for your help on this one, Gary. It'd be good to > get to the bottom of it so it doesn't bite you again. > > On Fri, Feb 27, 2015 at 11:13 AM, Gary Schulte > <[email protected]> wrote: > > James, > > > > When I simply added the skip scan hint, I got the same exception (even > with > > device_type criteria removed) but the indexes in the exception changed. > > Interesting - I wouldn't have expected adding a skip scan hint would have > > altered the plan, since it was already doing a skip scan. > > The hint tells Phoenix to keep using PK columns in the skip scan, > rather than stopping at the first PK column that isn't being filtered > on. We don't do this by default, because if the cardinality was very > high, we wouldn't want to do this. Since our stats don't yet capture > cardinality, we can't yet automatically do this. > > > > > 1: current region boundaries, linked so as not to clutter the list with > hex > > : http://goo.gl/hFSzYJ > > > > 2: table stats/guideposts, it looks like there are/were none. The output > > from the guidepost loop was : > > > > null > > > > (this was prior to deleting from system.stats) > > > > > > 3: deleting system.stats appears to have resolved the exception for both > the > > explicit varchar inlist and the skip_scan hint. Skip scanning the > reduced > > index space yields much faster results, ~5 seconds as opposed to 27. > > Glad to hear it's faster with the hint forcing the skip scan across > all your columns. > > I can't explain why deleting the stats resolved the issue, though, as > I would have expected (2) to have returned the stats. FYI, it looks > like the bug is in the code that intersects the guideposts with the > region boundaries. > > > > > Should I expect to rebuild stats often or is this more of an error case? > > Stats are rebuilt automatically when a major compaction occurs and are > updated as splits happen. They can also be manually updated by running > the following command: > > UPDATE STATISTICS PERF.BIG_OLAP_DOC > > For more info on stats, see > http://phoenix.apache.org/update_statistics.html > > If you run this command, does the problem start to reoccur? If so, > would you mind adding this command before running the loop to collect > the guideposts and let me know if you see that stats output? > > > > > Thanks again. > > > > > > > > On Thu, Feb 26, 2015 at 5:55 PM, James Taylor <[email protected]> > > wrote: > >> > >> Gary, > >> I'm not able to repro the issue - I filed PHOENIX-1690 to track it and > >> attached my test case there. It looks related to the particular state > >> the table is in wrt its region boundaries and current statistics, so > >> I'll need the following additional information to try to help me repro > >> this: > >> > >> 1) What are the current region boundaries of your table? You can get > >> this programmatically through code like this: > >> > >> Connection conn = DriverManager.getConnection(getUrl(), props); > >> List<HRegionLocation> splits = > >> > >> > conn.unwrap(PhoenixConnection.class).getQueryServices().getAllTableRegions(Bytes.toBytes("PERF.BIG_OLAP_DOC")); > >> for (HRegionLocation split : splits) { > >> > >> > System.out.println(Bytes.toStringBinary(split.getRegionInfo().getEndKey())); > >> } > >> > >> 2) What are the current stats for the table. You can get this by > >> programmatically through code like this: > >> > >> PTable table = > >> conn.unwrap(PhoenixConnection.class).getMetaDataCache().getTable(new > >> PTableKey(null, "PERF.BIG_OLAP_DOC")); > >> for (GuidePostsInfo info : > >> table.getTableStats().getGuidePosts().values()) { > >> for (byte[] gp : info.getGuidePosts()) { > >> System.out.println(Bytes.toStringBinary(gp)); > >> } > >> } > >> > >> 3) If you can try after removing all rows from the SYSTEM.STATS table > >> and let me know if the problem still occurs, that'd be helpful too. > >> You can just do the following from sqlline: DELETE FROM SYSTEM.STATS > >> and then exit sqlline, start it again, and rerun the original query. > >> > >> Thanks, > >> James > >> > >> On Thu, Feb 26, 2015 at 10:52 AM, James Taylor <[email protected]> > >> wrote: > >> > Gary, > >> > One possible workaround. Can you try adding the SKIP_SCAN hint to your > >> > query (instead of the AND device_type in > >> > ('MOBILE','DESKTOP','OTHER','TABLET')), like this? > >> > > >> > SELECT /*+ SKIP_SCAN */ count(1) cnt, > >> > ... > >> > > >> > Thanks, > >> > James > >> > > >> > On Wed, Feb 25, 2015 at 10:16 AM, James Taylor < > [email protected]> > >> > wrote: > >> >> Sounds like a bug. I'll try to repro on my end. Thanks for the > details, > >> >> Gary. > >> >> > >> >> James > >> >> > >> >> On Tue, Feb 24, 2015 at 1:49 PM, Gary Schulte > >> >> <[email protected]> wrote: > >> >>> On Tue, Feb 24, 2015 at 12:29 AM, James Taylor > >> >>> <[email protected]> > >> >>> wrote: > >> >>>> > >> >>>> Based on your query plan, the skip scan is being done solely based > on > >> >>>> your > >> >>>> salt bucket while the rest of the filtering is being done by a > >> >>>> filter, which > >> >>>> means that you're not filtering based on the leading part of your > >> >>>> primary > >> >>>> key. We'll know more once you post your schema, but if NETWORK, > >> >>>> KEYWORD_ID > >> >>>> and CUSTOMER_ID formed your primary key constraint, then the skip > >> >>>> scan would > >> >>>> work well. > >> >>>> > >> >>> > >> >>> Thanks for your response James. Sorry for the slow reply - I had > >> >>> difficulty > >> >>> finding the exact set of test queries I was using for timings. > >> >>> > >> >>> The relevant portion of the olap doc schema is: > >> >>> > >> >>> create table PERF.BIG_OLAP_DOC ( > >> >>> client_id integer not null > >> >>> ,customer_id integer > >> >>> ,time_id integer not null > >> >>> ,conversion_type_id integer not null > >> >>> ,device_type varchar(16) > >> >>> ,keyword_id bigint not null > >> >>> ,creative_id bigint not null > >> >>> ,placement_id bigint not null > >> >>> ,product_target_id bigint not null > >> >>> ,network varchar(7) > >> >>> ,impressions decimal(18, 4) > >> >>> ,publisher_clicks decimal(18, 4) > >> >>> ,publisher_cost decimal(18, 4) > >> >>> ,conversions decimal(18, 4) > >> >>> ,revenue decimal(18, 4) > >> >>> > >> >>> [ ...additional metric and dimensional colums ... ] > >> >>> > >> >>> constraint perf_fact_pk primary key (client_id, time_id, > >> >>> conversion_type_id, device_type, keyword_id, creative_id, > >> >>> placement_id, > >> >>> product_target_id))SALT_BUCKETS=10; > >> >>> > >> >>> > >> >>> I am evaluating a 'stitch' case where results from an external > system > >> >>> are > >> >>> injected either via table or (as in this case) an in-list. An > example > >> >>> of > >> >>> one of these test agg queries I am using is: > >> >>> > >> >>> SELECT count(1) cnt, > >> >>> coalesce(SUM(impressions), 0.0) AS "impressions", > >> >>> coalesce(SUM(publisher_clicks), 0.0) AS "pub_clicks", > >> >>> coalesce(SUM(publisher_cost), 0.0) AS "pub_cost", > >> >>> coalesce(SUM(conversions), 0.0) AS "conversions", > >> >>> coalesce(SUM(revenue), 0.0) AS "revenue" > >> >>> FROM perf.big_olap_doc > >> >>> WHERE time_id between 3000 and 3700 > >> >>> AND network in ('SEARCH') > >> >>> AND conversion_type_id = 1 > >> >>> AND client_id = 10724 > >> >>> -- AND device_type in ('MOBILE','DESKTOP','OTHER','TABLET') > >> >>> AND keyword_id in ( > >> >>> 613214369, 613217307, 613247509, 613248897, 613250382, 613250387, > >> >>> 613252322, > >> >>> 613260252, 613261753, 613261754, 613261759, > >> >>> 613261770, 613261873, 613261884, 613261885, 613261888, 613261889, > >> >>> 613261892, > >> >>> 613261897, 613261913, 613261919, 613261927, > >> >>> 614496021, 843606367, 843606967, 843607021, 843607033, 843607089, > >> >>> 1038731600, 1038731672, 1038731673, 1038731675, > >> >>> 1038731684, 1038731693, 1046990487, 1046990488, 1046990499, > >> >>> 1046990505, > >> >>> 1046990506, 1049724722, 1051109548, 1051311275, > >> >>> 1051311904, 1060574377, 1060574395, 1060574506, 1060574562, > >> >>> 1115915938, > >> >>> 1115915939, 1115915941, 1116310571, 1367495544, > >> >>> 1367495545, 1367497297, 1367497298, 1367497299, 1367497300, > >> >>> 1367497303, > >> >>> 1367497313, 1367497813, 1367497816, 1367497818, > >> >>> 1367497821, 1367497822, 1367497823, 1624976423, 1624976451, > >> >>> 1624976457, > >> >>> 3275636061, 3275640505, 3275645765, 3275645807, > >> >>> 3275649138, 3275651456, 3275651460, 3275651478, 3275651479, > >> >>> 3275654566, > >> >>> 3275654568, 3275654570, 3275654575, 3275659612, > >> >>> 3275659616, 3275659620, 3275668880, 3275669693, 3275675627, > >> >>> 3275675634, > >> >>> 3275677479, 3275677504, 3275678855, 3275679524, > >> >>> 3275679532, 3275680014, 3275682307, 3275682308, 3275682309, > >> >>> 3275682310, > >> >>> 3275682420, 3275682423, 3275682436, 3275682448, > >> >>> 3275682460, 3275682462, 3275682474, 3275684831, 3275688903, > >> >>> 3275694023, > >> >>> 3275694025, 3275694027, 3275695054, 3275695056, > >> >>> 3275695062, 3275699512, 3275699514, 3275699518, 3275701682, > >> >>> 3275701683, > >> >>> 3275701685, 3275701688, 3275703633, 3275703634, > >> >>> 3275703635, 3275703636, 3275703638, 3275703639, 3275704860, > >> >>> 3275704861, > >> >>> 3275764577, 3275797149, 3275798566, 3275798567, > >> >>> 3275798568, 3275798592, 3275931147, 3275942728, 3275945337, > >> >>> 3275945338, > >> >>> 3275945339, 3275945340, 3275945342, 3275945344, > >> >>> 3275946319, 3275946322, 3275946324, 3275946643, 3275949495, > >> >>> 3275949498, > >> >>> 3275949500, 3275950250, 3275955128, 3275955129, > >> >>> 3275955130, 3427017435, 3427017450, 3438304254, 3438304257, > >> >>> 3447068169, > >> >>> 3505227849, 3505227890, 3505556908, 3506351285, > >> >>> 3506351389, 3506351398, 3506351468, 3510037138, 3510038610, > >> >>> 3545590644, > >> >>> 3545594378, 3545595073, 3545595318, 3545595506, > >> >>> 3545597841, 3545598818, 3545599658, 3545599663, 3545601215, > >> >>> 3556080898, > >> >>> 3556080980, 3556080999, 3556081323, 3565122663, > >> >>> 3565122679, 3565122801, 3565122858, 3565122908, 3565122929, > >> >>> 3565122952, > >> >>> 3565122984, 3565123028, 3565123047, 3565123048, > >> >>> 3565123203, 3565123230, 3949988054, 3949988056, 3949988070, > >> >>> 3972992248, > >> >>> 3972992252, 3972992254, 3972992257, 3972992263, > >> >>> 3972992267, 3972992268, 3972992269, 3972992270, 3972992274, > >> >>> 3972992275, > >> >>> 3972992277, 3972992281, 3972992293, 3972992298, > >> >>> 3972992299, 3972992305, 3972992307, 3972992313, 3972992316, > >> >>> 3972992322, > >> >>> 3972992338, 3978471261, 3978471272, 4266318185, > >> >>> 4298107404, 4308853119, 4308853123, 4308853500, 4451174646, > >> >>> 4451174656, > >> >>> 4451174701, 4569827278, 4569827284, 4569827287, > >> >>> 4569827379, 4569827523, 4569827524, 4896589676, 4979049725, > >> >>> 5054587609, > >> >>> 5136433884, 5362640372, 5393109964, 5393405364, > >> >>> 5393405365, 5393405620, 5393405625, 5393405675, 5393405677, > >> >>> 5393405858, > >> >>> 5393405970) > >> >>> > >> >>> > >> >>> Reading your interpretation of the skip scan, I see that the plan is > >> >>> indicating it is only using the salt and the first three columns of > >> >>> the > >> >>> index, client_id, and time_id and conversion_type. I hadn't > >> >>> considered the > >> >>> salt - that bit of detail in the plan makes more sense to me now. > It > >> >>> looks > >> >>> now like the lackluster performance for higher cardinality > >> >>> aggregations is > >> >>> related to scanning a much larger portion of the key space. For > >> >>> aggregations where I am not relying on filtering, I am seeing much > >> >>> better > >> >>> performance. > >> >>> > >> >>> So to tune this particular stitch case / skip scan, it looks like I > >> >>> need to > >> >>> get the 4th index column into the criteria. There are only four > >> >>> distinct > >> >>> values in the fourth index column (these can/should probably be > >> >>> something > >> >>> other than varchar, but this is what I have loaded currently). In > >> >>> order to > >> >>> use the keyword_id portion of the index I tried explicitly > specifying > >> >>> all > >> >>> device_types via in-list (the commented portion of the query above), > >> >>> but I > >> >>> get a peculiar error: > >> >>> > >> >>> java.lang.IndexOutOfBoundsException: end index (1) must not be less > >> >>> than > >> >>> start index (2) > >> >>> at > >> >>> > >> >>> > com.google.common.base.Preconditions.checkPositionIndexes(Preconditions.java:388) > >> >>> at > >> >>> > com.google.common.collect.ImmutableList.subList(ImmutableList.java:362) > >> >>> at > >> >>> > com.google.common.collect.ImmutableList.subList(ImmutableList.java:62) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.filter.SkipScanFilter.intersect(SkipScanFilter.java:291) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.filter.SkipScanFilter.intersect(SkipScanFilter.java:177) > >> >>> at > >> >>> > org.apache.phoenix.compile.ScanRanges.intersectScan(ScanRanges.java:316) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.iterate.BaseResultIterators.getParallelScans(BaseResultIterators.java:464) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.iterate.BaseResultIterators.getParallelScans(BaseResultIterators.java:394) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.iterate.BaseResultIterators.<init>(BaseResultIterators.java:184) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.iterate.ParallelIterators.<init>(ParallelIterators.java:54) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.execute.AggregatePlan.newIterator(AggregatePlan.java:173) > >> >>> at > >> >>> > org.apache.phoenix.execute.BaseQueryPlan.iterator(BaseQueryPlan.java:227) > >> >>> at > >> >>> > org.apache.phoenix.execute.BaseQueryPlan.iterator(BaseQueryPlan.java:154) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.jdbc.PhoenixStatement$1.call(PhoenixStatement.java:226) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.jdbc.PhoenixStatement$1.call(PhoenixStatement.java:217) > >> >>> at org.apache.phoenix.call.CallRunner.run(CallRunner.java:53) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.jdbc.PhoenixStatement.executeQuery(PhoenixStatement.java:216) > >> >>> at > >> >>> > >> >>> > org.apache.phoenix.jdbc.PhoenixStatement.execute(PhoenixStatement.java:1057) > >> >>> at sqlline.SqlLine$Commands.execute(SqlLine.java:3673) > >> >>> at sqlline.SqlLine$Commands.sql(SqlLine.java:3584) > >> >>> at sqlline.SqlLine.dispatch(SqlLine.java:821) > >> >>> at sqlline.SqlLine.begin(SqlLine.java:699) > >> >>> at sqlline.SqlLine.mainWithInputRedirection(SqlLine.java:441) > >> >>> at sqlline.SqlLine.main(SqlLine.java:424) > >> >>> > >> >>> > >> >>> I thought perhaps I was hitting an upper limit on the number of > >> >>> elements in > >> >>> an in-list for a skip scan, and so tried removing the 250 element > >> >>> keyword > >> >>> in-list entirely and leaving only the device_type in-list, but I > still > >> >>> get > >> >>> the same error. It happens immediately, even for an explain, so I > >> >>> presume > >> >>> this is a query parsing problem. Is there a bug or limitation of > skip > >> >>> scans > >> >>> and/or sub lists involving varchar? > >> >>> > >> >>> Thx > >> >>> > >> >>> > >> >>> > > > > >
