wiki:drmsSubscribe

Version 3 (modified by niles, 10 years ago) (diff)

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Subscription and slony logs

Subscription

When a site 'subscribes' to a series, the process is initiated by the site sending a message to JSOC telling them that they're interested in that series. JSOC sends back the commands to build the table, and populate it to the current slony checkpoint. Then JSOC adds the table name to their list of what's being subscribed to by that site.

The only way to know if you're subscribed is to actually look in the lists at JSOC, which are named according to the convention:

/data/pgsql/slon_logs/live/etc/(site).lst

Slony logs

At JSOC, the logs are written to the directory :

/data/pgsql/slon_logs/live/site_logs/(site)

The slony logs have names according to the convention :

slony1_log_2_00000000000000690325.sql

Where the number 690325 is a counter that increments for each file. The term "log" is perhaps somewhat misleading with respect to these files, as they are not warnings or errors printed as the database operates. Rather, they are lists of database operations that have taken place at JSOC. If other sites are to keep in sync with JSOC, they must apply the same operations to their local databases. A typical log file may have entries like :

insert into "hmi"."rdvpspec_fd05" ("recnum","sunum","slotnum","sessionid","sessionns","ln_source_isset","ln_source_carrrot","ln_source_cmlon_index","ln_source_lonhg_index","ln_source_lathg_index",
"ln_source_loncm_index","cparms_sg000","logp_bzero","logp_bscale","carrrot","cmlon","lonhg","lathg","loncm","crpix1","crpix2","cdelt1","cdelt2","cdelt3","delta_k","delta_nu","d_omega","module",
"source","input","created","bld_vers","log_base","datamin","datamax","apode_f","apod_min","apod_max","cmlon_index","loncm_index","lathg_index","lonhg_index","sg_000_file","history") values
('9919708','528962345','0','27939659','su_rsb','1','2146','32','48','41','-32','','-8.48432540893554688','0.000635004483736478385','2146','200','120','-12.5','80','64.5','64.5',
'0.101023711','0.101023711','0.000181805124','0.101023711','28.9351845','0.000181805124','pspec3 v 1.1','hmi.rdVtrack_fd05[2146][200][120.0][-12.5][-80.0]',
'hmi.rdVtrack_fd05[2146][200]','1171214459','V8R2','2.71828182845904509','-29.1219711','12.1533213','0.96875','0.9765625','1','32','-32','41','48','logP.fits','');

insert into "hmi"."rdvpspec_fd05" ("recnum","sunum","slotnum","sessionid","sessionns","ln_source_isset","ln_source_carrrot","ln_source_cmlon_index","ln_source_lonhg_index","ln_source_lathg_index",
"ln_source_loncm_index","cparms_sg000","logp_bzero","logp_bscale","carrrot","cmlon","lonhg","lathg","loncm","crpix1","crpix2","cdelt1","cdelt2","cdelt3","delta_k","delta_nu","d_omega","module",
"source","input","created","bld_vers","log_base","datamin","datamax","apode_f","apod_min","apod_max","cmlon_index","loncm_index","lathg_index","lonhg_index","sg_000_file","history") values
('9919709','528962345','1','27939659','su_rsb','1','2146','32','48','42','-32','','-9.26125526428222656','0.000644568281907301633','2146','200','120','-15','-80','64.5','64.5',
'0.101023711','0.101023711','0.000181805124','0.101023711','28.9351845','0.000181805124','pspec3 v 1.1','hmi.rdVtrack_fd05[2146][200][120.0][-15.0][-80.0]',
'hmi.rdVtrack_fd05[2146][200]','1171214461','V8R2','2.71828182845904509','-30.2097244','11.6872139','0.96875','0.9765625','1','32','-32','42','48','logP.fits','');

After a while (daily?), these slony log files are archived into a bundle, named like so :

slony_logs_688467-689890.tar.gz

And then after a longer period of time - two weeks? - these archives of slony log files are deleted. It is critical that the slony logs are applied at remote sites before they deleted at JSOC.

Slony and the DRMS database

The small table _jsoc.sl_archive_tracking contains information about the most recent slony log ingested :

prompt> psql nso_drms

nso_drms=# select * from _jsoc.sl_archive_tracking;
 at_counter |         at_created         |        at_applied
------------+----------------------------+---------------------------
     886400 | 2014-06-27 09:36:17.452634 | 2014-06-27 16:37:03.71184