I have a table with many columns stored as text. These columns have information which i am planning to cast and copy the data into a fresh table with the same column names but with correct data types ( float8 )
I tested the SELECT with CAST operator "::" and it works fine. All the columns are being converted as you can see in the picture
However , when I uncomment the INSERT statement ( above it ) to start writing in the target table, it throws an error. The target table has identical column names and only float8 column types.
The expression from the source table is indeed of type text but i am using the cast operator so why does it not work like before when only running the SELECT statement?
My query below:
INSERT INTO "PM"."new_VM_gcell_evolution_hourly_BSC"
(select
"CR3120:Channel_Assignment_Failures_All_Channels_Busy_or_Channel"::float8,
"DL_Mean_Quality"::float8,
"A312Ca:Failed_Assignments_during_MTC_on_the_A_Interface_Includi"::float8,
"nsp_Urban_TA_4number"::float8,
"A3129C:Failed_Assignments_First_Assignment,_Assignment_Timed_Ou"::float8,
"R3120C:Channel_Assignment_Failures_All_Channels_Busy_or_Channel"::float8,
"TSs_Interf_B5"::float8,
"R3120D:Channel_Assignment_Failures_All_Channels_Busy_or_Channel"::float8,
"HO_Out_Internal_Succ_Rate"::float8,
"CH_Req_Protocol_Undefinednbnumber"::float8,
"UL_Drop_Congnumber"::float8,
"Timing_Adv"::float8,
"DL_Qual"::float8,
"A3100C:Assignment_Requests_TCHH_Only"::float8,
"MS_to_BTS_max_distance"::float8,
"TSs_Interf_B2"::float8,
"UL_Qual"::float8,
"UL_Drop_EDGE_Rate"::float8,
"Avg_BTS_Power_Level_AMR"::float8,
"DL_Drop_N3105number"::float8,
"nsp_Urban_TA_2_R"::float8,
"CH_Req_CallReestabnbnumber"::float8,
"TCH_Drops_cause_Timing_Advance"::float8,
"TCH_Drops_per_Erlang"::float8,
"UL_Drop_Flushnumber"::float8,
"A312F:Number_of_Assignment_Failures_No_Abis_Resource_Available"::float8,
"UL_Drop_GPRS_Rate"::float8,
"nsp_Urban_TA_3number"::float8,
"Call_Drop_rate"::float8,
"DL_Fail_Assingnumber"::float8,
"SDCCH_Radio_Failures"::float8,
"HO_Cmd_UL_Qual"::float8,
"UL/DL_RxQualnumber"::float8,
"UL/DL_RxLevnumber"::float8,
"UL_Fail_EDGE_Rate"::float8,
"Call_Drop_Total"::float8,
"HO_Out_Succ_Rate"::float8,
"Date"::text,
"A3127E:Failed_Assignments_during_Call_Reestablishment_on_the_Um"::float8,
"UL_Drop_N3103number"::float8,
"Configured_TCH"::float8,
"SDCCH_Drop_Call_Rate_only_LU"::float8,
"A312M:Failed_Assignments_Reconnection_to_Old_Channels,_No_Chann"::float8,
"SDCCH_Blocking_Rate"::float8,
"TCH_Drops_cause_DL_FER"::float8,
"TCH_Fail_rate"::float8,
"DL_Drop_Preemnumber"::float8,
"FR_Traffic_totalErl"::float8,
"DL_Congnumber"::float8,
"TCH_Assign_Unsuccnumber"::float8,
"nsp_Urban_TA_0_R"::float8,
"DL_Drop_GPRS_Rate"::float8,
"HR_TraficErl"::float8,
"SDCCH_Cong_Rate"::float8,
"Abis_and_Ater_Interface_Anlysistimes"::float8,
"A3100B:Assignment_Requests_TCHF_Only"::float8,
"AS4300D:Mean_Uplink_Level_during_Radio_Link_Failure_SDCCHdB"::float8,
"nsp_Urban_TA_89number"::float8,
"TCH_Drops_cause_DownQual"::float8,
"SDCCH_Drop_RxLev"::float8,
"Max_UL_Pwr_Duration"::float8,
"nsp_Channel_Req_LUnumber"::float8,
"TCH_HR_Initialy_Config"::float8,
"HO_Inc_Cong_Rate"::float8,
"DL_RxLev_avgdBm"::float8,
"TCH_Assign_Requestsnumber"::float8,
"A312K:Failed_Assignments_First_Assignment,_No_Channel_Available"::float8,
"Call_Drop_TCH_Quality_Rate"::float8,
"AMR_HR_TraficErl"::float8,
"nsp_Urban_TA_67_R"::float8,
"UL_Fail_MSnumber"::float8,
"Time"::text,
"TCH_Drops_cause_UpLevel"::float8,
"AMR_FR_TraficErl"::float8,
"TCH_FR_Initialy_Config"::float8,
"UL_Drop_N3101number"::float8,
"DL_FERnumber"::float8,
"SDCCH_Drop_Call_Rate_wo_LU"::float8,
"DL_Mean_StrengthdB"::float8,
"Call_Drop_Abis"::float8,
"SDCCH_Initialy_Confignumber"::float8,
"Call_Drop_TCH_RxLev_Rate"::float8,
"TA_Meannumber"::float8,
"nsp_Urban_TA_67number"::float8,
"AS3240NA:Average_MS_Power_Level_of_NonAMR_Call"::float8,
"Load"::float8,
"A3129Q:Failed_Assignments_Reconnection_to_Old_Channels,_Timer_E"::float8,
"CH_Request_11_bit"::float8,
"AS4340D:Mean_TA_during_Radio_Link_Failure_SDCCH"::float8,
"S4210A:Uplink_Interference_Indication_Messages_SDCCH"::float8,
"UL_FERnumber"::float8,
"A3129P:Failed_Assignments_Reconnection_to_Old_Channels,_Timer_E"::float8,
"K3003A:Successful_SDCCH_Seizures_Call_Type"::float8,
"CH_Req_LAUnbnumber"::float8,
"SDCCH_Drop_Rate"::float8,
"GBSC"::text,
"CS_CSSR_with_SDCCH_blocks_wo_LU"::float8,
"A312Aa:Failed_Assignments_during_MOC_on_the_A_Interface_Includi"::float8,
"Avg_BTS_Power_Level"::float8,
"R3120A:Channel_Assignment_Failures_All_Channels_Busy_or_Channel"::float8,
"A312S:Failed_Assignments_Signaling_Channel"::float8,
"SD_Fail_MoC"::float8,
"UL_RxQual_avg"::float8,
"Call_Drop_HO"::float8,
"AS4330D:Mean_Downlink_Quality_during_Radio_Link_Failure_SDCCH"::float8,
"CH_Req_Emerg_Callsnbnumber"::float8,
"UL_RxQualnumber"::float8,
"UL_Fail_OtherCausenumber"::float8,
"A312Da:Failed_Assignments_during_Emergency_Call_on_the_A_Interf"::float8,
"UL_Drop_Preemnumber"::float8,
"TCH_Drops_cause_UpDown_FER"::float8,
"AS4320D:Mean_Downlink_Level_during_Radio_Link_Failure_SDCCHdB"::float8,
"A3129O:Failed_Assignments_First_Assignment,_Directed_Retry_Time"::float8,
"Max_DL_Pwr_Duration"::float8,
"UL_Drop_Suspendnumber"::float8,
"TCH_Assign_Congestionnumber"::float8,
"Transmission_Resource_Analysistimes"::float8,
"HO_Out_RxQual_rate"::float8,
"nsp_Urban_TA_1013number"::float8,
"A3129I:Failed_Assignments_Invalid_State"::float8,
"DL_Fail_OtherCausenumber"::float8,
"CR3129:Channel_Assignment_Failures_All_Channels_Busy_or_Channel"::float8,
"HO_Inc_Successnumber"::float8,
"A3129B:Failed_Assignments_First_Assignment,_Terrestrial_Resourc"::float8,
"Trafic_totalErl"::float8,
"nsp_urban_TA_1463all_R"::float8,
"HO_Out_RxQualnumber"::float8,
"DL_RxQualnumber"::float8,
"HO_Inc_Succ_Rate"::float8,
"SDCCH_Fail_Rate"::float8,
"SDCCH_Non_Radio_Drops"::float8,
"nsp_Urban_TA_0number"::float8,
"A3129E:Failed_Assignments_CIC_Unavailable"::float8,
"nsp_CH_Request_PSnumber"::float8,
"TCH_Assign_Unsucc_rate"::float8,
"Call_Drop_Radio"::float8,
"EFR_TraficErl"::float8,
"A312L:Failed_Assignments_Reconnection_to_Old_Channels,_No_Chann"::float8,
"TCH_Drops_cause_DownLevel"::float8,
"nsp_Urban_TA_5number"::float8,
"Abnormal_Terminals_Analysistimes"::float8,
"HO_Inc_Congnumber"::float8,
"CSSR_Rate"::float8,
"M3020C:Call_Drops_on_SDCCHQuality"::float8,
"RH333:Handover_Drop_Rate_of_TCH"::float8,
"UL_Drop_EDGE_Abisnumber"::float8,
"A3129J:Failed_Assignments_Invalid_Message"::float8,
"TCH_Availability"::float8,
"UL_Level"::float8,
"nsp_Urban_TA_4_R"::float8,
"UL_Drop_OtherCausenumber"::float8,
"HR_Traffic_Rate"::float8,
"DL_Level"::float8,
"CH_Request_8_bit"::float8,
"UL_Fail_MS_Assingnumber"::float8,
"DL_Fail_BSC_Commandnumber"::float8,
"A3129R:Failed_Assignments_Reconnection_to_Old_Channels,_Reconne"::float8,
"UL_Fail_BSC_Commandnumber"::float8,
"DL_Drop_Suspendnumber"::float8,
"nsp_urban_TA_1463allnumber"::float8,
"Direct_Retry"::float8,
"nsp_Urban_TA_89_R"::float8,
"CH_Req_PSnbnumber"::float8,
"A3129N:Failed_Assignments_Reconnection_to_Old_Channels,_Terrest"::float8,
"A312A:Failed_Assignments_First_Assignment,_No_Channel_Available"::float8,
"nsp_Urban_TA_2number"::float8,
"DL_RxQual_avg"::float8,
"UL_Mean_StrengthdB"::float8,
"DL_Drop_EDGE_Rate"::float8,
"A3129T:Failed_Assignments_No_Ater_Resource_Available"::float8,
"TSs_Interf_B1"::float8,
"A3129D:Failed_Assignments_Reconnection_to_Old_Channels,_Reconne"::float8,
"nsp_Channel_Req_MOCnumber"::float8,
"UL_Fail_GPRS_Rate"::float8,
"S4210B:Downlink_Interference_Indication_Messages_SDCCH"::float8,
"R3120E:Channel_Assignment_Failures_All_Channels_Busy_or_Channel"::float8,
"HO_Inc_Failnumber"::float8,
"DL_Drop_Flushnumber"::float8,
"S3655:Number_of_configured_TRXs_in_a_cell"::float8,
"TCH_Drops_cause_UpDown_Qual"::float8,
"CR3005:Number_of_Initially_Configured_Channels_Static_PDTCH_Sup"::float8,
"UL/DL_FERnumber"::float8,
"SDCCH_Blocking_"::float8,
"HO_Out_InterRAT_Succ_Rate"::text,
"CM30E:Call_Drops_on_SDCCH_Location_Updating"::float8,
"AS4310D:Mean_Uplink_Quality_during_Radio_Link_Failure_SDCCH"::float8,
"UL_Congnumber"::float8,
"TAnumber"::float8,
"Configured_SDCCH"::float8,
"Othernumber"::float8,
"TCH_Assign_Fail_Radionumber"::float8,
"HO_Out_Internal_Req_Nb"::float8,
"SDCCH_Cong_Nbnumber"::float8,
"UL_Mean_Quality"::float8,
"HO_Out_External_Req_Nb"::float8,
"nsp_Urban_TA_1013_R"::float8,
"SDCCH_Drops_wo_LU"::float8,
"Call_Drop_TCH_Qualitynumber"::float8,
"A3100A:Assignment_Requests_Signaling_Channel_TCH"::float8,
"Better_Cell"::float8,
"Call_Drop_TCH_RxLevnumber"::float8,
"nsp_Channel_Req_MTCnumber"::float8,
"DL_Fail_EDGE_Rate"::float8,
"ZTR104B:Call_Drop_Rate_on_SDCCH_Call_Type"::float8,
"Call_Drop_no_MR"::float8,
"DL_Drop_Congnumber"::float8,
"HO_Inc_InterRAT_reqnumber"::float8,
"TCH_Assign_Cong_rate"::float8,
"HO_Inc_Fail_Rate"::float8,
"TCH_Assign_Fail_sp_ver_unav"::float8,
"HO_Inc_InterRAT_unsucc"::float8,
"A3170A:Number_of_Completed_TCH_Assignments_CSFB_MOC"::float8,
"HO_Inc_Unsucc_Rate"::float8,
"TSs_Interf_B4"::float8,
"A3100K:Assignment_Requests_Signaling_Channel_SDCCH"::float8,
"TCH_Drops_cause_UpDown_Level"::float8,
"SDCCH_Fail_Nbnumber"::float8,
"TCH_Non_Radio_Drops"::float8,
"DL_Fail_MSnumber"::float8,
"HO_Cmd_DL_Qual"::float8,
"DL_Drop_OtherCausenumber"::float8,
"SMS_on_SDCCH"::float8,
"FERnumber"::float8,
"HO_Inc_Reqnumber"::float8,
"nsp_Urban_TA_3_R"::float8,
"M3020D:Call_Drops_on_SDCCHOther"::float8,
"HO_Out_External_Succ_Rate"::float8,
"M3020A:Call_Drops_on_SDCCHTA"::float8,
"TCH_Assign_Fail_Radio_rate"::float8,
"CR3001:Number_of_Initially_Configured_Channels_Static_PDCH"::float8,
"HR_Traffic_totalErl"::float8,
"CH_Req_MTCnbnumber"::float8,
"SDCCH_Drop_RxQual"::float8,
"UL_RxLev_avgdBm"::float8,
"CH_Req_MOCnbnumber"::float8,
"SDCCH_Dropnumber"::float8,
"A3169A:Failed_Assignments_Um_Cause"::float8,
"A3129H:Failed_Assignments_Clear_Commands_Sent_By_MSC"::float8,
"TCH_Radio_Drops"::float8,
"HO_Out_InterRAT_Req_Nb"::float8,
"HO_Inc_InterRAT_succnumber"::float8,
"DL_Drop_Abisnumber"::float8,
"TCH_Drops_cause_UL_FER"::float8,
"UL_RxLevelnumber"::float8,
"nsp_CH_Request_CSnumber"::float8,
"A3170B:Number_of_Completed_TCH_Assignments_CSFB_MTC"::float8,
"A3129F:Failed_Assignments_CIC_Allocated"::float8,
"DL_Fail_GPRS_Rate"::float8,
"M3020B:Call_Drops_on_SDCCHReceived_Level"::float8,
"nsp_Urban_TA_1number"::float8,
"SDCCH_Availability"::float8,
"Call_Drop_forced_HO"::float8,
"SDCCH_Drop_Others"::float8,
"Call_Drop_Equip."::float8,
"CH_Req_PS"::float8,
"SDCCH_Drop_Call_Rate"::float8,
"TCH_Drops_cause_UpQual"::float8,
"CH_Req_LMU_Reservednbnumber"::float8,
"DL_RxLevnumber"::float8,
"nsp_Urban_TA_1_R"::float8,
"A312Ea:Failed_Assignments_during_Call_Reestablishment_on_the_A_"::float8,
"TSs_Interf_B3"::float8,
"SDCCH_Drop_TimingAdvance"::float8,
"Avg_BTS_Power_Level_NAMR"::float8,
"TCH_Drops_cause_Other"::float8,
"FR_TraficErl"::float8,
"Avg_MS_Power_Level"::float8,
"HO_Outgoing_Requestsnumber"::float8,
"A3129G:Failed_Assignments_A_Interface_Failure"::float8,
"CH_Req_LAU"::float8,
"nsp_Urban_TA_5_R"::float8,
"HO_Inc_Unsuccessnumber"::float8,
"AS3240A:Average_MS_Power_Level_of_AMR_Call"::float8
from "PM"."VM_gcell_evolution_hourly_BSC_recovered")
It says "column is of type double but expression is of type text" so what's really happening is that it's trying to insert one of the expressions where you cast to ::text into a column that is of type double.
If the problem was converting from text to double, you'd get a different message. Besides, the SELECT worked fine, which means it didn't encounter any text data that it couldn't convert to double.
Since you don't specify the target table columns in your INSERT, and you have so many of them, most likely you missed a column or got the order wrong.
Honestly if the table has 270 columns and they have the same name in the source and destination tables, you should really generate the query using something like python from a list of columns, that will be faster than proofreading the 270 lines...
Database :SNOWFLAKE
My table contains JSON data for example:
{
"bucket":"IN_Apps",
"bySeqno":56,
"cas":1527639206906626048,
"content":"eyJoaWdoQmluIjoiNTQ4NTA4MDkiLCJkb2N1bWVudFR5cGUiOiJJSU5ETyIsImNhcmRUeXBlIyayI6Ik1BU1RFUkNBUkQifQ==",
"event":"mutation",
"expiration":0,
"flags":33554432,
"key":"iin54850809",
"lockTime":0,
"partition":948,
"revSeqno":1,
"vBucketUuid":137987627737694
}
when i tried to parse it.
select
parse_json:bucket::string as bucket ,
parse_json:bySeqno::string as bySeqno ,
parse_json:cas::INT as cas ,
parse_json:content::string as content ,
parse_json:event::string as event
,parse_json:expiration::string as expiration
,parse_json:flags::string as flags
,parse_json:key::string as key
,parse_json:lockTime::string as lockTime
,parse_json:partition::string as partition
,parse_json:revSeqno::string as revSeqno
,parse_json:vBucketUuid::string as vBucketUuid
from STG_YS_APPS v
but it is throwing error like.
SQL compilation error: error line 2 at position 0 invalid identifier > >'PARSE_JSON'
may someone please help me.
Answer with a known schema
Update: Since you provided schema, which shows a VAR column of VARIANT type, here's what you need, couldn't be simpler:
select
var:bucket::string as bucket,
var:bySeqno::string as bySeqno,
var:cas::int as cas
...
from STG_YS_APPS v
Below the answer before the schema was known
I'll assume you have a VARCHAR (or similar) column in your table that is called json, and stores the values you presented. You didn't provide the schema, so please adjust the column name as necessary.
You're not using PARSE_JSON as a function in your SQL. You should write something like
select
parse_json(json):bucket::string as bucket,
parse_json(json):bySeqno::string as bySeqno,
parse_json(json):cas::int as cas
...
from STG_YS_APPS v
I'm looking for a more efficient way to run many columns updates on the same table like this:
UPDATE TABLE table
SET col = regexp_replace( col, 'foo', 'bar' )
WHERE regexp_match( col, 'foo' );
Such that foo, and bar, will be a combination of 40 different regex-replaces. I doubt even 25% of the dataset needs to be updated at all, but what I'm wanting to know is it is possible to cleanly achieve the following in SQL.
A single pass update
A single match of the regex, triggers a single replace
Not running all possible regexp_replaces if only one matches
Not updating all columns if only one needs the update
Not updating a row if no column has changed
I'm also curious, I know in MySQL (bear with me)
UPDATE foo SET bar = 'baz'
Has an implicit WHERE bar != 'baz' clause
However, in PostgreSQL I know this doesn't exist: I think I could at least answer one of my questions if I knew how to skip a single row's update if the target columns weren't updated.
Something like
UPDATE TABLE table
SET col = *temp_var* = regexp_replace( col, 'foo', 'bar' )
WHERE col != *temp_var*
Do it in code. Open up a cursor, then: grab a row, run it through the 40 regular expressions, and if it changed, save it back. Repeat until the cursor doesn't give you any more rows.
Whether you do it that way or come up with the magical SQL expression, it's still going to be a row scan of the entire table, but the code will be much simpler.
Experimental Results
In response to criticism, I ran an experiment. I inserted 10,000 lines from a documentation file into a table with a serial primary key and a varchar column. Then I tested two ways to do the update. Method 1:
in a transaction:
opened up a cursor (select for update)
while reading 100 rows from the cursor returns any rows:
for each row:
for each regular expression:
do the gsub on the text column
update the row
This takes 1.16 seconds with a locally connected database.
Then the "big replace," a single mega-regex update:
update foo set t =
regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(regexp_replace(t,
E'\bcommit\b', E'COMMIT'),
E'\b9acf10762b5f3d3b1b33ea07792a936a25e45010\b',
E'9ACF10762B5F3D3B1B33EA07792A936A25E45010'),
E'\bAuthor:\b', E'AUTHOR:'),
E'\bCarl\b', E'CARL'), E'\bWorth\b',
E'WORTH'), E'\b\b',
E''), E'\bDate:\b',
E'DATE:'), E'\bMon\b', E'MON'),
E'\bOct\b', E'OCT'), E'\b26\b',
E'26'), E'\b04:53:13\b', E'04:53:13'),
E'\b2009\b', E'2009'), E'\b-0700\b',
E'-0700'), E'\bUpdate\b', E'UPDATE'),
E'\bversion\b', E'VERSION'),
E'\bto\b', E'TO'), E'\b2.9.1\b',
E'2.9.1'), E'\bcommit\b', E'COMMIT'),
E'\b61c89e56f361fa860f18985137d6bf53f48c16ac\b',
E'61C89E56F361FA860F18985137D6BF53F48C16AC'),
E'\bAuthor:\b', E'AUTHOR:'),
E'\bCarl\b', E'CARL'), E'\bWorth\b',
E'WORTH'), E'\b\b',
E''), E'\bDate:\b',
E'DATE:'), E'\bMon\b', E'MON'),
E'\bOct\b', E'OCT'), E'\b26\b',
E'26'), E'\b04:51:58\b', E'04:51:58'),
E'\b2009\b', E'2009'), E'\b-0700\b',
E'-0700'), E'\bNEWS:\b', E'NEWS:'),
E'\bAdd\b', E'ADD'), E'\bnotes\b',
E'NOTES'), E'\bfor\b', E'FOR'),
E'\bthe\b', E'THE'), E'\b2.9.1\b',
E'2.9.1'), E'\brelease.\b',
E'RELEASE.'), E'\bThanks\b',
E'THANKS'), E'\bto\b', E'TO'),
E'\beveryone\b', E'EVERYONE'),
E'\bfor\b', E'FOR')
The mega-regex update takes 0.94 seconds to update.
At 0.94 seconds compared to 1.16, it's true that the mega-regex update is faster, running in 81% of the time of doing it in code. It is not, however a lot faster. And ye Gods, look at that update statement. Do you want to write that, or try to figure out what went wrong when Postgres complains that you dropped a parenthesis somewhere?
Code
The code used was:
def stupid_regex_replace
sql = Select.new
sql.select('id')
sql.select('t')
sql.for_update
sql.from(TABLE_NAME)
Cursor.new('foo', sql, {}, #db) do |cursor|
until (rows = cursor.fetch(100)).empty?
for row in rows
for regex, replacement in regexes
row['t'] = row['t'].gsub(regex, replacement)
end
end
sql = Update.new(TABLE_NAME, #db)
sql.set('t', row['t'])
sql.where(['id = %s', row['id']])
sql.exec
end
end
end
I generated the regular expressions dynamically by taking words from the file; for each word "foo", its regular expression was "\bfoo\b" and its replacement string was "FOO" (the word uppercased). I used words from the file to make sure that replacements did happen. I made the test program spit out the regex's so you can see them. Each pair is a regex and the corresponding replacement string:
[[/\bcommit\b/, "COMMIT"],
[/\b9acf10762b5f3d3b1b33ea07792a936a25e45010\b/,
"9ACF10762B5F3D3B1B33EA07792A936A25E45010"],
[/\bAuthor:\b/, "AUTHOR:"],
[/\bCarl\b/, "CARL"],
[/\bWorth\b/, "WORTH"],
[/\b<cworth#cworth.org>\b/, "<CWORTH#CWORTH.ORG>"],
[/\bDate:\b/, "DATE:"],
[/\bMon\b/, "MON"],
[/\bOct\b/, "OCT"],
[/\b26\b/, "26"],
[/\b04:53:13\b/, "04:53:13"],
[/\b2009\b/, "2009"],
[/\b-0700\b/, "-0700"],
[/\bUpdate\b/, "UPDATE"],
[/\bversion\b/, "VERSION"],
[/\bto\b/, "TO"],
[/\b2.9.1\b/, "2.9.1"],
[/\bcommit\b/, "COMMIT"],
[/\b61c89e56f361fa860f18985137d6bf53f48c16ac\b/,
"61C89E56F361FA860F18985137D6BF53F48C16AC"],
[/\bAuthor:\b/, "AUTHOR:"],
[/\bCarl\b/, "CARL"],
[/\bWorth\b/, "WORTH"],
[/\b<cworth#cworth.org>\b/, "<CWORTH#CWORTH.ORG>"],
[/\bDate:\b/, "DATE:"],
[/\bMon\b/, "MON"],
[/\bOct\b/, "OCT"],
[/\b26\b/, "26"],
[/\b04:51:58\b/, "04:51:58"],
[/\b2009\b/, "2009"],
[/\b-0700\b/, "-0700"],
[/\bNEWS:\b/, "NEWS:"],
[/\bAdd\b/, "ADD"],
[/\bnotes\b/, "NOTES"],
[/\bfor\b/, "FOR"],
[/\bthe\b/, "THE"],
[/\b2.9.1\b/, "2.9.1"],
[/\brelease.\b/, "RELEASE."],
[/\bThanks\b/, "THANKS"],
[/\bto\b/, "TO"],
[/\beveryone\b/, "EVERYONE"],
[/\bfor\b/, "FOR"]]
If this were a hand-generated list of regex's, and not automatically generated, my question is still appropriate: Which would you rather have to create or maintain?
For the skip update, look at suppress_redundant_updates - see http://www.postgresql.org/docs/8.4/static/functions-trigger.html.
This is not necessarily a win - but it might well be in your case.
Or perhaps you can just add that implicit check as an explicit one?